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          How to Improve Your Self-Control

"It's all right letting yourself go, as long as you can get yourself back." ~Mick Jagger

New research suggests self-control can be improved using abstract reasoning.

Temptation comes in many forms, often so potent, so animal, that it seems impossible to resist. Eating too much, drinking too much, spending too much or letting the heart rule the head. We get instant messages from deep in the gut that resonate through the mind, trying to dictate our behaviour.

One of humanity's most useful skills, without which advanced civilisations would not exist, is being able to engage our higher cognitive functions, our self-control, to resist these temptations. Psychologists have found that self-control is strongly associated with what we label success: higher self-esteem, better interpersonal skills, better emotional responses and, perhaps surprisingly, few drawbacks at even very high levels of self-control (Tangney et al., 2004).

People, being only human, find the constant battle with basic urges is frequently too great and their self-control buckles. However, recent experimental research by Dr Kentaro Fujita at Ohio State University and colleagues has explored ways of improving self-control, where it comes from and why it sometimes deserts us.

Based on new research, along with studies conducted over the past few decades, Dr Fujita and colleagues have proposed that abstract thinking and psychological distance are particularly important in self-control.

                1. Evidence that abstract thinking improves self-control

It never ceases to amaze just how different two people's views of exactly the same event can be: one person's freedom fighter is another's terrorist. But the way in which we view people or events isn't just constrained by unchangeable patterns of thought that are set in stone. Dr Fujita and colleagues explored the idea that simple manipulations of how we construe the world can have a direct effect on self-control. Their hunch was that thinking from a more abstract, high-level perspective increases self-control.

In their research, published in the Journal of Personality and Social Psychology, Fujita et al. (2006) used a number of experiments to test the idea that self-control is affected by how we construe or interpret events. The problem for the researchers was manipulating aspects of people's construal without them realising: this required some deception.

In one of Fujita et al.'s (2006) studies participants were told they were going to take part in two separate experiments - one on personality and another billed as a student survey. In fact this was just a cover story as the two pieces of research were designed to work together.

Experimenters used the 'student survey' as a cover to manipulate levels of construal. They needed participants to be thinking in either a high-level way (abstract - seeing the whole forest) or a low-level way (concrete - seeing individual trees). They did this by getting participants to think about their level of physical health, but in two different ways:

·       High-level construal condition: participants were asked to fill in a diagram which encouraged them to think about why they maintain good physical health. Participants tended to put answer such as: "To do well in school." This got them thinking about ends rather than means - the ultimate purpose of physical health.

·       Low-level construal condition: in contrast participants in this condition were asked to think about how they maintained their physical health. Naturally they responded with things like: "Go exercise". In other words they focused on means rather than ends, the actual process.

Just before this manipulation of construal level, in a study they were misinformed was separate, participants were told their personality was being tested physiologically through holding a handgrip. This handgrip was designed to be difficult to squeeze together but participants were told to hold on as long as possible. This provided a baseline measurement of their grip strength.

Just after the manipulation of construal level participants had dummy electrodes attached to their arm and were told that their personality could be measured while they squeezed the stiff handgrip again. This time, though, they were told that the longer they could squeeze the handgrip the more accurate the information would be. The question was: how well could participants forget the temporary discomfort of holding the handgrip once they had been told about the desired goal of getting information about their own personalities?

The results confirmed Fujita et al.'s (2006) suspicions. They showed that participants in the low-construal thinking condition (thinking about means rather than ends) held on to the handgrip for, on average, 4.9 seconds less than they had during the baseline measurement.

In contrast those in the high-construal condition held on for 11.1 seconds longerthan their baseline measurement. Whether participants were thinking about means or ends had a really significant effect on how long they squeezed the handgrip. Those participants who had been encouraged to think in high-level, abstract terms demonstrated greater self-control in enduring the discomfort of the handgrip in order to receive more accurate personality profiles.

Along with this design Fujita et al. (2006) also carried out other studies using different measures of self-control and different ways of inducing either high-level or low-level construal. These produced similar findings. People in the high-level construal condition were consistently:

·       More likely to avoid the temptation of instant gratification.

·       Prepared to make a greater investment to learn more about their health status.

·       Less likely to evaluate temptations like beer and television positively.

                2. How personality and the situation affect self-control

Self-control is not just affected by how we are thinking at a specific moment, that would be too easy. We have each developed different amounts of self-control. Some people seem to find it easy to resist temptation while others can be relied on to always yield to self-gratification. To a certain extent we have to accept our starting point on the self-control sliding scale and do the best we can with it.

Although a few people have very high (or very low) levels of self-control, two-thirds of us lie somewhere near the middle: sometimes finding it easy to resist temptation, other times not. Naturally the exact situation has a huge effect on how much self-control we can exert. One property of different situations central to self-control that psychologists have examined is 'psychological distance'.

Research reveals that people find it much easier to make decisions that demonstrate self-control when they are thinking about events that are distant in time, for example how much exercise they will do next week or what they will eat tomorrow (Fujita, 2008). Similarly they make much more disciplined decisions on behalf of other people than they do for themselves. People implicitly follow the maxim: do what I say, not what I do.

It's not hard to see the convergence between the idea of 'psychological distance' and high-level construal. Both emphasise the idea that the more psychological or conceptual distance we can put between ourselves and the particular decision or event, the more we are able to think about it in an abstract way, and therefore the more self-control we can exert. It's all about developing a special type of objectivity.

                3. How to improve your self-control

Fujita et al.'s (2006) studies, along with other similar findings reported by Fujita (2008), suggest that self-control can be increased by these related ways of thinking:

·       Global processing. This means trying to focus on the wood rather than the trees: seeing the big picture and our specific actions as just one part of a major plan or purpose. For example, someone trying to eat healthily should focus on the ultimate goal and how each individual decision about what to eat contributes (or detracts) from that goal.

·       Abstract reasoning. This means trying to avoid considering the specific details of the situation at hand in favour of thinking about how actions fit into an overall framework - being philosophical. Someone trying to add more self-control to their exercise regime might try to think less about the details of the exercise, and instead focus on an abstract vision of the ideal physical self, or how exercise provides a time to re-connect mind and body.

·       High-level categorisation. This means thinking about high-level concepts rather than specific instances. Any long-term project, whether in business, academia or elsewhere can easily get bogged down by focusing too much on the minutiae of everyday processes and forgetting the ultimate goal. Categorising tasks or project stages conceptually may help an individual or group maintain their focus and achieve greater self-discipline.

These are just some examples of specific instances, but with a little creativity the same principles can be applied to many situations in which self-control is required. Ultimately these three ways of thinking are different ways of saying much the same thing: avoid thinking locally and specifically and practice thinking globally, objectively and abstractly, and increased self-control should follow.

Blu - ray Disc Format - All you need to know

Blu - ray Disc Format - All you need to know

We have been hearing a lot about new and old Bollywood and Hollywood movie titles being released and re-released on Blu-ray. But, have you ever wondered what that Blu-ray disc actually is, when you saw it sitting right next to the good old DVD, in that electronics store? Well, to be brutally honest, you aren’t the only one wondering about the same question. Party because on the outside, the Blu-ray disc looks exactly like a standard DVD. And mostly because the price of the Blu-ray is at times more than twice of that of a DVD title. A lot of people have been asking what Blu-ray is and how it is different from the DVDs we have been using for quite a while now.

Blu-ray: The simple definition
Blu-ray is, essentially, a new optical disc format, which supports storing huge amounts of data into one optical disc. A single layer Blu-ray disc holds about 25GB of data and a dual layer Blu-ray disc holds about 50GB of data. These discs can not only hold more data than a standard CD or DVD (even the dual layer ones), but are also extremely useful for High Definition movies. This format has been developed in association by a combination of big names in the technology sector- Sony, Panasonic, Mitsubishi, Philips, Samsung, HP, Dell, Apple, Sharp, Pioneer, LG, TDK and Thomson. These brands have come together under the umbrella of Blu-ray Disc Association (BDA).

Blu-ray’s working: The case of the blue laser
While on the outside, the Blu-ray looks exactly similar to the traditional DVD disc. However, while the DVD uses a red laser to read and write data from and to the disc, the Blu-ray uses a blue laser, all this while in an optical drive. This solves the mystery behind the name Blu-ray! And this is why the standard DVD players cannot read a Blu-ray disc. The blue laser has higher precision and is thinner than the red laser, which allows pristine focus on one spot, without getting distracted by the data around it. The Blu-ray format uses this precision advantage to pack in more data in the disc. A single layer DVD holds about 4.7GB of data, while a dual layer one can hold a bit more than 8GB of data. However, a single layer Blu-ray disc can store about 25GB of data, while the dual layer goes up to 50GB. Pioneer is working on a 20-layer disc, which can hold about 500GB of data on one disc. This particular disc is till in the prototype phase.

Blu-ray: The advantages
The Blu-ray has a lot of advantages over the good old DVD disc.

More data in one disc: As we have discussed earlir, the Blu-ray disc has a huge advantage over the older generation DVD disc. Maximum of about 8.5GB versus a current maximum of 50GB, there really is no competition. One disc can usually be enough to back up an entire music library, rather than spreading them over a bunch of discs.

High Definition content: Since they are able to store more data, the Blu-ray discs are perfect for high definition movies. The DVD can hold a maximum of 480p (720x480 pixels) while the Blu-ray will be able to hold movies in the 1080p resolution (1920x1080 pixels). For the movie buffs, this is superb news. Apart from the resolution advantage, Blu-ray discs are also capable of working with high-res audio formats like DTS-HD and Dolby True HD. Most Blu-ray movies have high-def audio as well.

Backward compatible hardware: Okay, this one is a largely hardware specific point, but all Blu-ray players, be it the standalone ones or the internal drives for PCs/laptops, will read almost all DVDs and older optical discs (assuming they are not scratched or damaged). Essentially, when you buy a Blu-ray player, it is a DVD player as well.

 

Blu-ray: The disadvantages
While the newer Blu-ray format has its share of advantages over the older DVD format, it has its share of limitations and drawbacks.

High cost: The entire Blu-ray ecosystem is quite expensive. A standalone Blu-ray player will cost you anywhere upwards of Rs 8k, depending on the configuration and how many features have been stripped down. A Blu-ray movie will cost anywhere between Rs 500 and Rs 2,000, depending on the title, the publisher and the genre. Contrast this to a standalone DVD player and the DVD discs. A decent DVD player will be available from about Rs 2,000 (with video upscaling capabilities), while a movie DVD will cost anywhere between Rs 100 and Rs 500. This will put off a lot of people.

Limited library: The limited availability of movies on the Blu-ray format is something that is changing, quite fast. Studios are re-releasing popular Hollywood movies in the Blu-ray format. However, the availability of Bollywood flicks in this format is still very limited. That needs to change quickly, before we will see a rise in Blu-ray hardware uptake.

Lack of hardware access: Unlike with a DVD disc, you cannot always carry this with you to your friend’s place and hope it will work. Blu-ray discs cannot be read by the traditional DVD drives, and most people haven’t upgraded to the newer hardware, largely due to the high cost of acquisition.

Blu-ray: The compatible hardware & devices
Since Blu-ray discs need dedicated compatible hardware, you will need to buy one which best fits your requirement.

For the PC/laptop: Essentially, you will be swapping the existing optical drive on your computing device with a Blu-ray capable one. These drives require no intervention during the hardware driver detection and installation (assuming you have the latest gen Operating System installed and updated). Once installed, the device is ready for use. As for the installing the hardware, we suggest you check with the PC/laptop manufacturer as to which drive is compatible with your PC/Laptop, and the safest method of installing it.

Stand-alone player: On the outside, this one looks like a DVD player, but since it can throw blue coloured lasers on the inside, this one is the more loaded of the two siblings! Connect this to your TV using the HDMI cable, slot in a disc and you are ushered into the world of High Definition.

Blu-ray Home Theaters: We have seen DVD based home theaters. However, swap that DVD player with a Blu-ray capable one and we have a completely updated hardware, with home theater speakers for the complete audio experience. Philips, Sony and Samsung offer these Blu-ray home theater setups, with prices starting from Rs 19k.

Playstation 3 console: This one serves a dual purpose- console for the hardcore gamer, and the Blu-ray player for the High Definition movie buff. We find these traits in the same person as well, at times, and this makes the PS3 a superb deal. For about Rs 20k (depends on whether you pick up the older gen PS3, or the newer PS3 Slim), you get both devices.

Blu-ray devices: Which ones to buy
Well, if you are convinced that you need the Blu-ray upgrade in your life, check out these devices. You may want to buy one of these.

LG BD550 Blu-ray player: Rs 8,500
This is one of the most inexpensive Blu-ray players available out there. For the movie playback, you get Full HD playback of the Blu-ray movies and full HD upscaling of Standard Definition DVD videos. Built in network capablities and USB 2.0 Media Host. The network capability allows the player to connect to the Internet and allow access to You Tube, Picasa, AccuWeather etc. This could very well be your first Blu-ray player, and the price versus features comparison makes this a real value for money purchase.

Sony BDP S-370 Blu-ray player: Rs 9,900
This one just barely manages to stay under the Rs 10k price bracket, but the features offered at unmatched. The XMB menu interface gives it a perfect blend of functionality and looks, along with a PS3-esque aura. If you are connecting this to a Sony Bravia television or a Sony home theater, the BRAVIA Sync will allow you to use one remote for controlling all devices. Network capability is futher boosted by the availability of the Wi-Fi adapter.

Philips BDP5012/F7 Blu-ray player: Rs 13,000
This one does everything the other Blu-ray players do, and then some! The fact that this also has a memory card reader, opens up more avenues to access media from. Copy movies to a memory card, slot it in, and the BDP5012/F7 will upscale even SD videos to Full HD resolutions. Slightly expensive than the three we had mentioned earlier, but the marginal boost in features may just be worth the extra moolah.

Samsung BD-C5900 Blu-ray player: Rs 13,500
Apart from the HD upscaling capabilities and all the fun features which come with a Blu-ray disc, the Samsung BD-C5900 is 3D ready as well. This means that if you have already purchased a 3D TV, or are planning to buy one, it’ll make sense to buy this one. Is wireless network access capable, with an optional compatible wireless adapter plugged in.

LG BD590 Blu-ray player: Rs 18,500
You must be wondering why this Blu-ray player is so expensive, considering that it’ll largely offer what the lower priced rivals are offering. Well, this one has a 250GB hard drive built-in, for you to store multimedia on, and get instant playback. The storage space, we believe, alone makes this worth the price.

Philips HTS3251B Blu-ray Home Theatre system: Rs 28,500
Essentially, this setup offers the full-fledged Blu-ray player along with the goodies of a home theater. Well, after all, you need a home theater to enjoy a Blu-ray movie. Buy this, and get the entire package in one box. A 5.1 channel setup (5 speakers and 1 woofer), along with an iPod dock to boot, and the package is complete!

Sony Playstation 3/ Sony Playstation 3 Slim: Rs 19,000 onwards
This one serves a dual purpose- console for the hardcore gamer, and the Blu-ray player for the movie buff. We find these traits in the same person as well, at times, and this makes the PS3 a superb deal. For about Rs 20k (depends on whether you pick up the older gen PS3, or the newer PS3 Slim+ the hard drive capacity), you get the functionality of both devices in one.
 

What is normalization? Explain different levels of normalization?

What is normalization? Explain different levels of normalization?
DBCC CHECKTABLE,
DBCC CHECKCATALOG,
DBCC CHECKALLOC,
DBCC SHOWCONTIG,
DBCC SHRINKDATABASE,
DBCC SHRINKFILE etc.
STATS_DATE,
DBCC SHOW_STATISTICS,
CREATE STATISTICS,
DROP STATISTICS,
sp_autostats,
sp_createstats,
sp_updatestats
Detaching and attaching databases,
Replication,
DTS,
BCP,
logshipping,
INSERT...SELECT,
SELECT...INTO,
creating INSERT scripts to generate data.
    * Transactional replication (with immediate updating subscribers, with queued updating subscribers)
    * Merge replication
Dynamic,
Forward-only,
Keyset-driven.
Salary between 40000 and 55000 -- 7000 hike
Salary between 55000 and 65000 -- 9000 hike
CASE WHEN salary BETWEEN 30000 AND 40000 THEN salary + 5000
WHEN salary BETWEEN 40000 AND 55000 THEN salary + 7000
WHEN salary BETWEEN 55000 AND 65000 THEN salary + 10000
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FULL OUTER JOINS.
SYSTEM_USER,
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empid int,
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empname char(10)
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INSERT emp SELECT 3,NULL,'Shobha'
INSERT emp SELECT 4,2,'Shridhar'
INSERT emp SELECT 5,2,'Sourabh'
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Query:  Select A.firstname , B.firstname
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where A.supervisor_id = B.employee_id;
ACID - Atomicity, Consistency, Isolation and Durability, these are the unique entities of a transaction.
                SQL Interview Questions and Answers :
ex: create trigger after Insert on
yes,
USER_CONSTRAINTS,
system table contains information on constraints on all the tables created
Normalisation means refining the redundancy and maintain stablisation. there are four types of normalisation :
first normal forms, second normal forms, third normal forms and fourth Normal forms.
Select * from global_name;
This will give the datbase name which u r currently connected to.....
whereas
Structured Query Language (SQL), pronounced "sequel", is a language that provides an interface to relational database systems. It was developed by IBM in the 1970s for use in System R. SQL is a de facto standard, as well as an ISO and ANSI standard. SQL is used to perform various operations on RDBMS.
Pattern matching operator is LIKE and it has to used with two attributes
2) What are disadvantages in Oracle and MS Access?
3) What are feratures&advantages in Oracle and MS Access?
Oracle's features for distributed transactions, materialized views and replication are not available with MS Access. These features enable Oracle to efficiently store data for multinational companies across the globe. Also these features increase scalability of applications based on Oracle.
A database is a collection of data that is organized so that itscontents can easily be accessed, managed and updated. open this url : http://www.webopedia.com/TERM/d/database.html
Clustered Index:- A Clustered index is a special type of index that reorders the way records in the table are physically stored. Therefore table may have only one clustered index.Non-Clustered Index:- A Non-Clustered index is a special type of index in which the logical order of the index does not match the physical stored order of the rows in the disk. The leaf nodes of a non-clustered index does not consists of the data pages. instead the leaf node contains index rows.
you can hide the table name by creating synonyms.
The main difference of DBMS & RDBMS is
the DBMS hasn't normalization concept.
datediff

Check out the article Q100139 from Microsoft knowledge base and of course, there's much more information available in the net. It will be a good idea to get a hold of any RDBMS fundamentals text book, especially the one by C. J. Date. Most of the times, it will be okay if you can explain till third normal form.

What is de-normalization and when would you go for it?

As the name indicates, de-normalization is the reverse process of normalization. It is the controlled introduction of redundancy in to the database design. It helps improve the query performance as the number of joins could be reduced.

How do you implement one-to-one, one-to-many and many-to-many relationships while designing tables?

One-to-One relationship can be implemented as a single table and rarely as two tables with primary and foreign key relationships. One-to-Many relationships are implemented by splitting the data into two tables with primary key and foreign key relationships. Many-to-Many relationships are implemented using a junction table with the keys from both the tables forming the composite primary key of the junction table.

It will be a good idea to read up a database designing fundamentals text book.

What's the difference between a primary key and a unique key?

Both primary key and unique enforce uniqueness of the column on which they are defined. But by default primary key creates a clustered index on the column, where are unique creates a non-clustered index by default. Another major difference is that, primary key does not allow NULLs, but unique key allows one NULL only.

What are user defined data types and when you should go for them?

User defined data types let you extend the base SQL Server data types by providing a descriptive name, and format to the database. Take for example, in your database, there is a column called Flight_Num which appears in many tables. In all these tables it should be varchar(8). In this case you could create a user defined data type called Flight_num_type of varchar(8) and use it across all your tables.

See sp_addtype, sp_droptype in books online.

What is bit data type and what's the information that can be stored inside a bit column?

Bit data type is used to store Boolean information like 1 or 0 (true or false). Until SQL Server 6.5 bit data type could hold either a 1 or 0 and there was no support for NULL. But from SQL Server 7.0 onwards, bit data type can represent a third state, which is NULL.

Define candidate key, alternate key, composite key.

A candidate key is one that can identify each row of a table uniquely. Generally a candidate key becomes the primary key of the table. If the table has more than one candidate key, one of them will become the primary key, and the rest are called alternate keys.

A key formed by combining at least two or more columns is called composite key.

What are defaults? Is there a column to which a default cannot be bound?

A default is a value that will be used by a column, if no value is supplied to that column while inserting data. IDENTITY columns and timestamp columns can't have defaults bound to them. See CREATE DEFAULT in books online.

What is a transaction and what are ACID properties?

A transaction is a logical unit of work in which, all the steps must be performed or none. ACID stands for Atomicity, Consistency, Isolation, Durability. These are the properties of a transaction. For more information and explanation of these properties, see SQL Server books online or any RDBMS fundamentals text book.

Explain different isolation levels

An isolation level determines the degree of isolation of data between concurrent transactions. The default SQL Server isolation level is Read Committed. Here are the other isolation levels (in the ascending order of isolation): Read Uncommitted, Read Committed, Repeatable Read, Serializable. See SQL Server books online for an explanation of the isolation levels. Be sure to read about SET TRANSACTION ISOLATION LEVEL, which lets you customize the isolation level at the connection level.

CREATE INDEX myIndex ON myTable (myColumn)

What type of Index will get created after executing the above statement?

Non-clustered index. Important thing to note: By default a clustered index gets created on the primary key, unless specified otherwise.

What is the maximum size of a row?

8060 bytes. Do not be surprised with questions like 'What is the maximum number of columns per table'. Check out SQL Server books online for the page titled: "Maximum Capacity Specifications".

Explain Active/Active and Active/Passive cluster configurations

Hopefully you have experience setting up cluster servers. But if you do not, at least be familiar with the way clustering works and the two clustering configurations Active/Active and Active/Passive. SQL Server books online has enough information on this topic and there is a good white paper available on Microsoft site.

Explain the architecture of SQL Server

This is a very important question and you better be able to answer it if consider yourself a DBA. SQL Server books online is the best place to read about SQL Server architecture. Read up the chapter dedicated to SQL Server Architecture.

What is Lock Escalation?

Lock escalation is the process of converting a lot of low level locks (like row locks, page locks) into higher level locks (like table locks). Every lock is a memory structure too many locks would mean, more memory being occupied by locks. To prevent this from happening, SQL Server escalates the many fine-grain locks to fewer coarse-grain locks. Lock escalation threshold was definable in SQL Server 6.5, but from SQL Server 7.0 onwards it's dynamically managed by SQL Server.

What's the difference between DELETE TABLE and TRUNCATE TABLE commands?

DELETE TABLE is a logged operation, so the deletion of each row gets logged in the transaction log, which makes it slow. TRUNCATE TABLE also deletes all the rows in a table, but it will not log the deletion of each row, instead it logs the de-allocation of the data pages of the table, which makes it faster. Of course, TRUNCATE TABLE can be rolled back.

Explain the storage models of OLAP

Check out MOLAP, ROLAP and HOLAP in SQL Server books online for more information.

What are the new features introduced in SQL Server 2000 (or the latest release of SQL Server at the time of your interview)? What changed between the previous version of SQL Server and the current version?

This question is generally asked to see how current is your knowledge. Generally there is a section in the beginning of the books online titled "What's New", which has all such information. Of course, reading just that is not enough, you should have tried those things to better answer the questions. Also check out the section titled "Backward Compatibility" in books online which talks about the changes that have taken place in the new version.

What are constraints? Explain different types of constraints.

Constraints enable the RDBMS enforce the integrity of the database automatically, without needing you to create triggers, rule or defaults.

Types of constraints: NOT NULL, CHECK, UNIQUE, PRIMARY KEY, FOREIGN KEY

For an explanation of these constraints see books online for the pages titled: "Constraints" and "CREATE TABLE", "ALTER TABLE"

What is an index? What are the types of indexes? How many clustered indexes can be created on a table? I create a separate index on each column of a table. what are the advantages and disadvantages of this approach?

Indexes in SQL Server are similar to the indexes in books. They help SQL Server retrieve the data quicker.

Indexes are of two types. Clustered indexes and non-clustered indexes. When you create a clustered index on a table, all the rows in the table are stored in the order of the clustered index key. So, there can be only one clustered index per table. Non-clustered indexes have their own storage separate from the table data storage. Non-clustered indexes are stored as B-tree structures (so do clustered indexes), with the leaf level nodes having the index key and it's row locater. The row located could be the RID or the Clustered index key, depending up on the absence or presence of clustered index on the table.

If you create an index on each column of a table, it improves the query performance, as the query optimizer can choose from all the existing indexes to come up with an efficient execution plan. At the same time, data modification operations (such as INSERT, UPDATE, DELETE) will become slow, as every time data changes in the table, all the indexes need to be updated. Another disadvantage is that, indexes need disk space, the more indexes you have, more disk space is used.

What is RAID and what are different types of RAID configurations?

RAID stands for Redundant Array of Inexpensive Disks, used to provide fault tolerance to database servers. There are six RAID levels 0 through 5 offering different levels of performance, fault tolerance. MSDN has some information about RAID levels and for detailed information, check out the RAID advisory board's homepage

What are the steps you will take to improve performance of a poor performing query?

This is a very open ended question and there could be a lot of reasons behind the poor performance of a query. But some general issues that you could talk about would be: No indexes, table scans, missing or out of date statistics, blocking, excess recompilations of stored procedures, procedures and triggers without SET NOCOUNT ON, poorly written query with unnecessarily complicated joins, too much normalization, excess usage of cursors and temporary tables.

Some of the tools/ways that help you troubleshooting performance problems are:

·       SET SHOWPLAN_ALL ON,

·       SET SHOWPLAN_TEXT ON,

·       SET STATISTICS IO ON,

·       SQL Server Profiler,

·       Windows NT /2000 Performance monitor,

·       Graphical execution plan in Query Analyzer.

Download the white paper on performance tuning SQL Server from Microsoft web site.

What are the steps you will take, if you are tasked with securing an SQL Server?

Again this is another open ended question. Here are some things you could talk about: Preferring NT authentication, using server, database and application roles to control access to the data, securing the physical database files using NTFS permissions, using an unguessable SA password, restricting physical access to the SQL Server, renaming the Administrator account on the SQL Server computer, disabling the Guest account, enabling auditing, using multi-protocol encryption, setting up SSL, setting up firewalls, isolating SQL Server from the web server etc.

Read the white paper on SQL Server security from Microsoft website. Also check out My SQL Server security best practices

What is a deadlock and what is a live lock? How will you go about resolving deadlocks?

Deadlock is a situation when two processes, each having a lock on one piece of data, attempt to acquire a lock on the other's piece. Each process  would wait indefinitely for the other to release the lock, unless one of the user processes is terminated. SQL Server detects deadlocks and terminates one user's process.

A livelock is one, where a  request for an exclusive lock is repeatedly denied because a series of overlapping shared locks keeps interfering. SQL Server detects the situation after four denials and refuses further shared locks. A livelock also occurs when read transactions monopolize a table or page, forcing a write transaction to wait indefinitely.

Check out SET DEADLOCK_PRIORITY and "Minimizing Deadlocks"  in SQL Server books online. Also check out the article Q169960 from Microsoft knowledge base.

What is blocking and how would you troubleshoot it?

Blocking happens when one connection from an application holds a lock and a second connection requires a conflicting lock type. This forces the second connection to wait, blocked on the first.

Read up the following topics in SQL Server books online: Understanding and avoiding blocking, Coding efficient transactions.

Explain CREATE DATABASE syntax

Many of us are used to creating databases from the Enterprise Manager or by just issuing the command:

CREATE DATABASE MyDB.

But what if you have to create a database with two file groups, one on drive C and the other on drive D with log on drive E with an initial size of 600 MB and with a growth factor of 15%? That's why being a DBA you should be familiar with the CREATE DATABASE syntax. Check out SQL Server books online for more information.

How to restart SQL Server in single user mode? How to start SQL Server in minimal configuration mode?

SQL Server can be started from command line, using the SQLSERVR.EXE. This EXE has some very important parameters with which a DBA should be familiar with. -m is used for starting SQL Server in single user mode and -f is used to start the SQL Server in minimal configuration mode. Check out SQL Server books online for more parameters and their explanations.

As a part of your job, what are the DBCC commands that you commonly use for database maintenance?

DBCC CHECKDB,

But there are a whole load of DBCC commands which are very useful for DBAs. Check out SQL Server books online for more information.

What are statistics, under what circumstances they go out of date, how do you update them?

Statistics determine the selectivity of the indexes. If an indexed column has unique values then the selectivity of that index is more, as opposed to an index with non-unique values. Query optimizer uses these indexes in determining whether to choose an index or not while executing a query.

Some situations under which you should update statistics:

1.  If there is significant change in the key values in the index

2.  If a large amount of data in an indexed column has been added, changed, or removed (that is, if the distribution of key values has changed), or the table has been truncated using the TRUNCATE TABLE statement and then repopulated

3.  Database is upgraded from a previous version

Look up SQL Server books online for the following commands:

UPDATE STATISTICS,

What are the different ways of moving data/databases between servers and databases in SQL Server?

There are lots of options available, you have to choose your option depending upon your requirements. Some of the options you have are:

BACKUP/RESTORE,

Explain different types of BACKUPs available in SQL Server? Given a particular scenario, how would you go about choosing a backup plan?

Types of backups you can create in SQL Sever 7.0+ are Full database backup, differential database backup, transaction log backup, filegroup backup. Check out the BACKUP and RESTORE commands in SQL Server books online. Be prepared to write the commands in your interview. Books online also has information on detailed backup/restore architecture and when one should go for a particular kind of backup.

What is database replication? What are the different types of replication you can set up in SQL Server?

Replication is the process of copying/moving data between databases on the same or different servers. SQL Server supports the following types of replication scenarios:

    * Snapshot replication

See SQL Server books online for in-depth coverage on replication. Be prepared to explain how different replication agents function, what are the main system tables used in replication etc.

How to determine the service pack currently installed on SQL Server?

The global variable @@Version stores the build number of the sqlservr.exe, which is used to determine the service pack installed. To know more about this process visit SQL Server service packs and versions.

What are cursors? Explain different types of cursors. What are the disadvantages of cursors? How can you avoid cursors?

Cursors allow row-by-row processing of the resultsets.

Types of cursors:

Static,

See books online for more information.

Disadvantages of cursors: Each time you fetch a row from the cursor, it results in a network roundtrip, where as a normal SELECT query makes only one round trip, however large the resultset is. Cursors are also costly because they require more resources and temporary storage (results in more IO operations). Further, there are restrictions on the SELECT statements that can be used with some types of cursors.

Most of the times, set based operations can be used instead of cursors. Here is an example:

If you have to give a flat hike to your employees using the following criteria:

Salary between 30000 and 40000 -- 5000 hike

In this situation many developers tend to use a cursor, determine each employee's salary and update his salary according to the above formula. But the same can be achieved by multiple update statements or can be combined in a single UPDATE statement as shown below:

UPDATE tbl_emp SET salary =

Another situation in which developers tend to use cursors: You need to call a stored procedure when a column in a particular row meets certain condition. You don't have to use cursors for this. This can be achieved using WHILE loop, as long as there is a unique key to identify each row.

Write down the general syntax for a SELECT statements covering all the options.

Here's the basic syntax: (Also checkout SELECT in books online for advanced syntax).

SELECT select_list

What is a join and explain different types of joins?

Joins are used in queries to explain how different tables are related. Joins also let you select data from a table depending upon data from another table.

Types of joins:

INNER JOINs,

OUTER JOINs are further classified as

LEFT OUTER JOINS,

For more information see pages from books online titled: "Join Fundamentals" and "Using Joins".

Can you have a nested transaction?

Yes, very much. Check out BEGIN TRAN, COMMIT, ROLLBACK, SAVE TRAN and @@TRANCOUNT

What is an extended stored procedure? Can you instantiate a COM object by using T-SQL?

An extended stored procedure is a function within a DLL (written in a programming language like C, C++ using Open Data Services (ODS) API) that can be called from T-SQL, just the way we call normal stored procedures using the EXEC statement. See books online to learn how to create extended stored procedures and how to add them to SQL Server.

Yes, you can instantiate a COM (written in languages like VB, VC++) object from T-SQL by using sp_OACreate stored procedure.

Also see books online for sp_OAMethod, sp_OAGetProperty, sp_OASetProperty, sp_OADestroy.

What is the system function to get the current user's user id?

USER_ID(). Also check out other system functions like

USER_NAME(),

What are triggers? How many triggers you can have on a table? How to invoke a trigger on demand?

Triggers are special kind of stored procedures that get executed automatically when an INSERT, UPDATE or DELETE operation takes place on a table.

In SQL Server 6.5 you could define only 3 triggers per table, one for INSERT, one for UPDATE and one for DELETE. From SQL Server 7.0 onwards, this restriction is gone, and you could create multiple triggers per each action. But in 7.0 there's no way to control the order in which the triggers fire. In SQL Server 2000 you could specify which trigger fires first or fires last using sp_settriggerorder

Triggers cannot be invoked on demand. They get triggered only when an associated action (INSERT, UPDATE, DELETE) happens on the table on which they are defined.

Triggers are generally used to implement business rules, auditing. Triggers can also be used to extend the referential integrity checks, but wherever possible, use constraints for this purpose, instead of triggers, as constraints are much faster.

Till SQL Server 7.0, triggers fire only after the data modification operation happens. So in a way, they are called post triggers. But in SQL Server 2000 you could create pre triggers also. Search SQL Server 2000 books online for INSTEAD OF triggers.

Also check out books online for 'inserted table', 'deleted table' and COLUMNS_UPDATED()

There is a trigger defined for INSERT operations on a table, in an OLTP system. The trigger is written to instantiate a COM object and pass the newly inserted rows to it for some custom processing.

What do you think of this implementation? Can this be implemented better?

Instantiating COM objects is a time consuming process and since you are doing it from within a trigger, it slows down the data insertion process. Same is the case with sending emails from triggers. This scenario can be better implemented by logging all the necessary data into a separate table, and have a job which periodically checks this table and does the needful.

What is a self join? Explain it with an example.

Self join is just like any other join, except that two instances of the same table will be joined in the query. Here is an example: Employees table which contains rows for normal employees as well as managers. So, to find out the managers of all the employees, you need a self join.

CREATE TABLE emp

INSERT emp SELECT 1,2,'Vyas'

SELECT t1.empname [Employee], t2.empname [Manager]

Here is an advanced query using a LEFT OUTER JOIN that even returns the employees without managers (super bosses)

SELECT t1.empname [Employee], COALESCE(t2.empname, 'No manager') [Manager]

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Q1 - Write a query to find the total number of rows in a table

A1 - Select count(*) from t_employee;

Q2 - Write a query to eliminate duplicate records in the results of a table

A2 - Select distinct * from t_employee;

Q3 - Write a query to insert a record into a table

A3 - Insert into t_employee values ('empid35','Barack','Obama');

Q4 - Write a query to delete a record from a table

A4 - delete from t_employee where id='empid35';

Q5 - Write a query to display a row using index

A5 - For this, the indexed column of the table needs to be set as a parameter in the where clause

select * from t_employee where id='43';

Q6 - Write a query to fetch the highest record in a table, based on a record, say salary field in the t_salary table

A6 - Select max(salary) from t_salary;

Q7 - Write a query to fetch the first 3 characters of the field designation from the table t_employee

A7 - Select substr(designation,1,3) from t_employee; -- Note here that the substr function has been used.

Q8 - Write a query to concatenate two fields, say Designation and Department belonging to a table t_employee

Select Designation + ‘ ‘ + Department from t_employee;

Q9 -What is the difference between UNION and UNION ALL in SQL?

A9 - UNION is an SQL keyword used to merge the results of two or more tables using a Select statement, containing the same fields, with removed duplicate values. UNION ALL does the same, however it persists duplicate values.

Q10 - If there are 4 SQL Select statements joined using Union and Union All, how many times should a Union be used to remove duplicate rows?

A10 - One time.

Q11 - What is the difference between IN and BETWEEN, that are used inside a WHERE clause?

A11 - The BETWEEN clause is used to fetch a range of values, whereas the IN clause fetches data from a list of specified values.

Q12 - Explain the use of the ‘LIKE’ keyword used in the WHERE clause? Explain wildcard characters in SQL.

A12 - LIKE is used for partial string matches. The symbol ‘%’ ( for a string of any character ) and ‘_’ (for any single character ) are the two wild card characters used in SQL.

Q13 - What is the need to use a LIKE statement?

A13 - When a partial search is required in a scencario, where for instance, you need to find all employees with the last name having the sequence of characters "gat", then you may use the following query, to match a search criteria:

Select empid, firstname, lastname from t_employee where lastname like ‘%gats%’

This might search all employees with last name containing the character sequence 'gats' like Gates, Gatsby, Gatsburg, Sogatsky, etc.

% is used to represent remaining all characters in the name. This query fetches all records contains gats in the e middle of the string.

Q14 - Explain the use of the by GROUP BY and the HAVING clause.

A14 - The GROUP BY partitions the selected rows on the distinct values of the column on which the group by has been done. In tandem, the HAVING selects groups which match the criteria specified.

Q15 - In a table t_employee, the department column is nullable. Write a query to fetch employees which are not assigned a department yet.

A11.  Select empid, firstname, lastname from t_employee where department is null;

Q16 -What are the large objects supported by oracle and db2? What are the large objects supported in MS SQL?

A16 - In Oracle and DB2 BLOB , CLOB ( Binary Large Objects, Character Large Objects) are used.

In MS SQL - the data types are image and varbinary.

Q17 - Whats the capacity of the image data type in MS SQL?

A17 - Variable-length binary data with a maximum length of 2^31 - 1 (2,147,483,647) bytes.

Q18 - Whats the capacity of varbinary data type in MS SQL?

A18 - Variable-length binary data with a maximum length of 8,000 bytes.

Q19 - What’s the difference between a primary key and a unique key?

A19 - Both Primary key and Unique key enforce the uniqueness of a column on which they are defined. However, a Primary key does not allow nulls, whereas unique key allow nulls.

Q20 - What are the different types of joins in SQL?

INNER JOIN

Read here for more http://www.dotnetuncle.com/SQL/What-is-Join-in-SQL-types-of-joins.aspx

Q21 - What is a Self join?

A21 - A join created by joining two or more instances of a same table.

Q22 - What is a transaction and ACID?

A22 - Transaction - A transaction is a logical unit of work. All steps must be committed or rolled back.

What is the difference between oracle,sql and sql server ?

·       Oracle is based on RDBMS.

·       SQL is Structured Query Language.

·       SQL Server is another tool for RDBMS provided by MicroSoft.

why you need indexing ? where that is stroed and what you mean by schema object? For what purpose we are using view?

We cant create an Index on Index.. Index is stoed in user_index table.Every object that has been created on Schema is Schema Object like Table,View etc.If we want to share the particular data to various users we have to use the virtual table for the Base table...So tht is a view.

indexing is used for faster search or to retrieve data faster from various table. Schema containing set of tables, basically schema means logical separation of the database. View is crated for faster retrieval of data. It's customized virtual table. we can create a single view of multiple tables. Only the drawback is..view needs to be get refreshed for retrieving updated data.

Difference between Store Procedure and Trigger?

·       we can call stored procedure explicitly.

·       but trigger is automatically invoked when the action defined in trigger is done.

·       this trigger invoked after we insert something on that table.

·       Stored procedure can't be inactive but trigger can be Inactive.

·       Triggers are used to initiate a particular activity after fulfilling certain condition.It need to define and can be enable and disable according to need.

What is the advantage to use trigger in your PL?

Triggers are fired implicitly on the tables/views on which they are created. There are various advantages of using a trigger. Some of them are:

·       Suppose we need to validate a DML statement(insert/Update/Delete) that modifies a table then we can write a trigger on the table that gets fired implicitly whenever DML statement is executed on that table.

·       Another reason of using triggers can be for automatic updation of one or more tables whenever a DML/DDL statement is executed for the table on which the trigger is created.

·       Triggers can be used to enforce constraints. For eg : Any insert/update/ Delete statements should not be allowed on a particular table after office hours. For enforcing this constraint Triggers should be used.

·       Triggers can be used to publish information about database events to subscribers. Database event can be a system event like Database startup or shutdown or it can be a user even like User loggin in or user logoff.

What the difference between UNION and UNIONALL?

Union will remove the duplicate rows from the result set while Union all does'nt.

What is the difference between TRUNCATE and DELETE commands?

Both will result in deleting all the rows in the table .TRUNCATE call cannot be rolled back as it is a DDL command and all memory space for that table is released back to the server. TRUNCATE is much faster.Whereas DELETE call is an DML command and can be rolled back.

Which system table contains information on constraints on all the tables created ?

Explain normalization ?

How to find out the database name from SQL*PLUS command prompt?

What is the difference between SQL and SQL Server ?

SQLServer is an RDBMS just like oracle,DB2 from Microsoft

What is diffrence between Co-related sub query and nested sub query?

Correlated subquery runs once for each row selected by the outer query. It contains a reference to a value from the row selected by the outer query.

Nested subquery runs only once for the entire nesting (outer) query. It does not contain any reference to the outer query row.

For example,

Correlated Subquery:

select e1.empname, e1.basicsal, e1.deptno from emp e1 where e1.basicsal = (select max(basicsal) from emp e2 where e2.deptno = e1.deptno)

Nested Subquery:

select empname, basicsal, deptno from emp where (deptno, basicsal) in (select deptno, max(basicsal) from emp group by deptno)

WHAT OPERATOR PERFORMS PATTERN MATCHING?

1. % and

2. _ ( underscore )

% means matches zero or more characters and under score means mathing exactly one character

1)What is difference between Oracle and MS Access?

What is database?

What is cluster.cluster index and non cluster index ?

How can i hide a particular table name of our schema?

e.g) you can create a synonym y for table x

create synonym y for x;

What is difference between DBMS and RDBMS?

RDBMS have Normalization. Normalization means to refining the redundant and maintain the stablization.

What are the advantages and disadvantages of primary key and foreign key in SQL?

Primary key

Advantages

1) It is a unique key on which all the other candidate keys are functionally dependent

Disadvantage

1) There can be more than one keys on which all the other attributes are dependent on.

Foreign Key

Advantage

1)It allows refrencing another table using the primary key for the other table

Which date function is used to find the difference between two dates?

for Eg: select datediff (dd,'2-06-2007','7-06-2007')

output is 5

1. Q. What does SQL stand for? 

   A. Structured Query Language

   Q. Who was E. F. Codd?

   A. He was the original inventor of the relational model.

2. Q. How do you select all records from the table?

   A. Select * from table_name;

   Q. What do you understand by the term referential integrity?

3. Q. What is a join?

   A. Join is a process of retrieve pieces of data from different sets (tables) and returns them to the user or program as one “joined” collection of data.

4. Q. What kinds of joins do you know? Give examples.

   A. We have self join, outer joint (LEFT, RIGHT), , cross-join ( Cartesian product n*m rows returned)

Exp:

outer joint

SELECT Employee.Name, Department. DeptName

FROM Employee, Department

WHERE Employee.Employee_ID = Department.Employee_ID;

cross-join

SELECT * FROM table1, table2;

self join

SELECT e1.name | |’    ‘ | | e2.ename FROM emp e1, emp e2 WHERE e1. emp_no = e2.emp_no;

The following summarizes the result of the join operations:

 The result of T1 INNER JOIN T2 consists of their paired rows where the

join-condition is true.

 The result of T1 LEFT OUTER JOIN T2 consists of their paired rows where

the join-condition is true and, for each unpaired row of T1, the

concatenation of that row with the null row of T2. All columns derived

from T2 allow null values.

 The result of T1 RIGHT OUTER JOIN T2 consists of their paired rows

where the join-condition is true and, for each unpaired row of T2, the

concatenation of that row with the null row of T1. All columns derived

from T1 allow null values.

The result of T1 FULL OUTER JOIN T2 consists of their paired rows and,

for each unpaired row of T2, the concatenation of that row with the null

row of T1 and, for each unpaired row of T1, the concatenation of that row

with the null row of T2. All columns derived from T1 and T2 allow null

values.

5. Q. How do you add record to a table?

   A. INSERT into table_name VALUES (‘ALEX’ , 33 , ‘M’);

6.  Q. How do you add a column to a table?

    A. ALTER TABLE Department

      ADD (AGE,  NUMBER);

7.  Q. How do you change value of the field?

    A. UPDATE EMP_table

       set  number = 200 where item_munber = ‘CD’;

update name_table set status = 'enable'  where phone = '4161112222';

update SERVICE_table set REQUEST_DATE = to_date ('2006-03-04 09:29', 'yyyy-mm-dd hh24:MI') where phone = '4161112222';

8.  Q. What does COMMIT do?

    A. Saving all changes made by DML statements

9.  Q. What is a primary key?

    A. The column  (columns) that has completely unique data throughout

the table is known as the primary key field.

10. Q. What are foreign keys?

    A. Foreign key field – is a field that links one table

to another table’s primary or foreign key.

11. Q. What is the main role of a primary key in a table?

    A. The main role of a primary key in a data table is to maintain the internal integrity of a data table.

12. Q. Can a table have more than one foreign key defined?

    A. A table can have any number of foreign keys defined. It can have only

       one primary key defined.

13. Q. List all the possible values that can be stored in a BOOLEAN data field.

     A. There are only two values that can be stored in a BOOLEAN data field:

         -1(true) and 0(false).

14  Q. What is the highest value that can be stored in a BYTE data field?

    A. The highest value that can be stored in a BYTE field is 255. or from -128

       to 127. Byte is a set of Bits that represent a single character.

        Usually there are 8 Bits in a Byte, sometimes more, depending on how

        the measurement is being made. Each Char requires one byte of memory

        and can have a value from 0 to 255 (or 0 to 11111111 in binary).

15.  Q. How many places to the right of the decimal can be stored in a

         CURRENCY data field?

     A. The CURRENCY data type can store up to four places to the right of the

        decimal. Any data beyond the fourth place will be truncated by Visual

        Basic without reporting an error.

16.  Q. What is a stored procedure?

     A. A procedure is a group of PL/SQL statements that can be called by

        a name. Procedures do not return values they perform tasks.

17.  Q. Describe how NULLs work in SQL?

     A. The NULL is how SQL handles missing values.

      Arifthmetic operation with NULL in SQL will return a NULL.

18.  Q. What is Normalization?

     A. The process of table design is called normalization.

19.   Q. What is referential integrity constraints?

      A. Referential integrity constraints are rules

       that are partnof the table in a database schema.

20.    Q. What is Trigger?

       A. Trigger will execute a block of procedural code

       against the database when a table event occurs.

       A2. A trigger defines a set of actions that are performed in response

       to an insert, update, or delete operation on a specified table. When 

       such an  SQL operation is executed, in this case the trigger has been

       activated.

21.    Q. Which of the following WHERE clauses will return only rows

 that have a NULL in the PerDiemExpenses column?

A.      WHERE PerDiemExpenses <>

B.      WHERE PerDiemExpenses IS NULL

C.      WHERE PerDiemExpenses = NULL

D.      WHERE PerDiemExpenses NOT IN (*)

      A. B is correct � When searching for a NULL value in a column, you must

 use the  keyword IS. No quotes are required around the keyword NULL.

22.   Q. You issue the following query:SELECT FirstName FROM

StaffListWHERE FirstName LIKE'_A%'Which names would be

returned by this query? Choose all that apply.

A.      Allen

B.      CLARK

C.      JACKSON

D.      David

      A. C is correct � Two wildcards are used with the LIKE operator.

The underscore (_) stands for any one character of any

case, and the percent sign (%) stands for any number of

characters of any case including none. Because this string

starts with an underscore rather than a percent sign, it won't

return Allen or Clark because they represent zero and two

characters before the "A". If the LIKE string had been "%A%",

both of these values would have been returned.

David was not returned because all non-wild card characters

are case sensitive. Therefore, only strings

with an uppercase "A" as their second letter are returned

23.   Q. Write a SQL SELECT query that only returns each city only once from Students table?

Do you need to order this list with an ORDER BY clause?

      A. SELECT DISTINCT City

FROM Students;

The Distinct keyword automatically sorts all data

 in ascending order. However, if you want the data

 sorted in descending order, you have to use an ORDER BY clause

24.    Q. Write a SQL SELECT sample of the concatenation operator.

       A.  SELECT LastName ||',' || FirstName, City FROM Students;

25.    Q. How to rename column in the SQL SELECT query?

       A.  SELECT LastName ||',' || FirstName

          AS "Student Name", City AS "Home City"

           "FROM StudentsORDER BY "Student Name"

26.   Q. Write SQL SELECT example how you limiting the rows returned with a WHERE clause.

      A. SELECT InstructorID, Salary FROM Instructors

WHERE Salary > 5400 AND Salary < 6600;

27.   Q. Write SQL SELECT query that returns the first and

last name of each instructor, the Salary,

and gives each of them a number.

       A. SELECT FirstName, LastName, Salary,

ROWNUM FROM Instructors;

28.    Q. Which of the following functions can be used only with numeric values?

(Choose all that apply.)

A.      AVG

B.      MIN

C.      LENGTH

D.      SUM

E.      ROUND

       A. A and D � Only A and D are correct. The MIN function

works with any character, numeric, or date datatype.

The LENGTH function is a character function that returns

the number of letters in a character value. The ROUND

function works with both numeric and date values.

29. Q.  Which function do you use to remove all padded characters

to the right of a character value in a column with a char datatype?

A.      RTRIM

B.      RPAD

C.      TRIM

     A.  C � The TRIM function is used to remove padded spaces.

LTRIM and RTRIM functions were included in earlier versions

of Oracle, but Oracle 8i has replaced them with a single

TRIM function

30.  Q. Which statement do you use to eliminate padded spaces

 between the month and day values in a function TO_CHAR(SYSDATE,'Month, DD, YYYY') ?

     A. To remove padded spaces, you use the "fm"

prefix before the date element that contains the spaces.

     TO_CHAR(SYSDATE,'fmMonth DD, YYYY')

31. Q. Is the WHERE clause must appear always before the GROUP BY clause in SQL SELECT ?

    A. Yes.

The proper order for SQL SELECT

clauses is: SELECT, FROM, WHERE, GROUP BY, HAVING, ORDER BY.

Only the SELECT and FROM clause are mandatory.

32. Q. How Oracle executes a statement with nested subqueries?

    A. When Oracle executes a statement with nested subqueries,

it always executes the innermost query first. This query passes its

results to the next query and so on until it reaches the outermost query.

It is the outermost query that returns a result set.

33. Q. Which operator do you use to return all of the rows

from one query except rows are returned in a second query?

    A. You use the MINUS operator to return all rows from one query except

where duplicate rows are found in a second query. The UNION operator

returns all rows from both queries minus duplicates. The UNION ALL operator

returns all rows from both queries including duplicates.

The INTERSECT operator returns only those rows that exist in both queries.

34. Q. How you will create a column alias? (Oracle 8i)

    A. The AS keyword is optional when specifying a column alias.

You must enclose the column alias in double quotes when the alias

contains a space or lowercase letters. If you specify an alias in l

owercase letters without double quotes, the alias will appear in uppercase.

35  Q. Which of the following statements are Data Manipulation Language commands?

A.      INSERT

B.      UPDATE

C.      GRANT

D.      TRUNCATE

E.      CREATE

    A.  A and B � The INSERT and UPDATE statements are

Data Manipulation Language (DML) commands.

GRANT is a Data Control Language (DCL) command.

TRUNCATE and CREATE are Data Definition Language (DDL) commands

36. Question. What is Oracle locking?

    A. Oracle uses locking mechanisms to protect data from

being destroyed by concurrent transactions.

37. Question. What Oracle lock modes do you know?

     A.  Oracle has two lock modes: shared or exclusive.

Shared locks are set on database resources so that many transactions

 can access the resource.

Exclusive locks are set on resources that ensure

one transaction has exclusive access to the database resource

38.  Question. What is query optimization?

     A.  Query optimization is the part of the query

process in which the database system compares

different query strategies and chooses the one with

the least expected cost

39.  Question. What are the main components of Database management systems software.

     A. The database management system software includes

 components for storage management, concurrency control, transaction

processing, database manipulation interface, database definition interface,

and database control interface.

40.  Question. What are the main attributes of  database management system?

     A. A database management system is composed of five elements: computer hardware, software, data, people (users), and operations procedures.

41.  Question. What is transaction?

      A. A transaction is a collection of applications

code and database manipulation code bound into an indivisible unit of execution.

it consists from:

BEGIN-TRANSACTION Name

Code

END TRANSACTION Name

42.  Question.  What databases do you know?

Informix       

DB2    

SQL    

Oracle

43.  Question. Explain SQL SELECT example:

     select j.FILE_NUM

  from DB_name.job j, DB_name.address a

where j.JOB_TYPE ='C'

  AND j.COMPANY_NAME = 'TEST6'

  AND j.OFFICE_ID = '101'

  AND j.ACTIVE_IND = 'Y'

  AND a.ADDRESS_STATUS_ID = 'H'

  AND a.OFFICE_ID = '101'

  AND a.FILE_NUM = j.FILE_NUM order by j.FILE_NUM;

    Answer: j and a aliases for table names. this is outer joint select statament from two tables.

44.  Q. Describe some Conversion Functions that you know

      A. TO_CHAR converts a number / date to a string.

         TO_DATE converts a string (representing a date) to a date.

         TO_NUMBER converts a character string containing digits to a numeric data type, it accepts one parameter which is a column value or a string literal

45.   Q.  Describe some Group Functions that you know

A. 1) The COUNT function tells you how many rows were in the result set.

      SELECT COUNT(*) FROM TESTING.QA

    2) The AVG function tells you the average value of a numeric column.

       SELECT MAX(SALARY) FROM TESTING.QA

    3) The MAX and MIN functions tell you the maximum and minimum value of a numeric column.

       SELECT MIN(SALARY) FROM TESTING.QA 

     4) The SUM function tells you the sum value of a numeric column.

        SELECT SUM(SALARY) FROM TESTING.QA

46. Question. What does DML stand for? 

     A. DML is Data Manipulation Language statements. (SELECT)

47. Question. What does DDL stand for?

    A. DDL is Data Definition Language statements. (CREATE)

48.  Question. What does DCL stand for?

     A. DCL is Data Control Language statements. (COMMIT)

49.  Question: Describe SQL comments.

     A. SQL comments are introduced by two consecutive hyphens

     (--) and ended by the end of the line.

50.   Q. In what sequence SQL statement are processed?

      A. The clauses of the subselect are processed in the following sequence (DB2):

1. FROM clause

2. WHERE clause

3. GROUP BY clause

4. HAVING clause

5. SELECT clause

6. ORDER BY clause

7. FETCH FIRST clause

51.    Q. Describe TO_DATE function.

       A. The TO_DATE function returns a timestamp from a character string

that has been interpreted using a character template.

TO_DATE is a synonym for TIMESTAMP_FORMAT.

52.    Question:

 In the domain table we have status as a numeric value from 01 to 04 and we

 have text definition of these values in the design document.

 Write SQL query to see the result as a text definitions that is corresponded

 to these values. (DB2)

      A. select TB1.member_id, TB1.bu_id, TB1.program,  TB2.num,

        case TB1.status

                when '01' then 'Auto renew'

                when '02' then 'Expired'

                when '03' then 'Sold'

                when '04' then ‘Terminated’

               

        else TB_name.status

        end

        from DB_name.TB_name1  TB1,

        DB_name.TB_name2 TB2

        where

        TB1.program in ('com', 'org')

        and TB1.member_role  = '100'

        order by  TB1.member_id

        fetch first 30 rows only

53. Question:

What's the logical difference, if any, between the following SQL expressions?

SELECT COUNT ( * ) FROM T

SELECT SUM ( 1 ) FROM T

 A. They're the same unless table T is empty, in which case the first yields

a one-column, one-row table containing a zero and the second yields a one-column,

one-row table "containing a null."