ASP.NET: Interview Questions

Hi, These are the typical questions that i usually asks while taking an ASP.NET specific interview. Hope these might help someone :)

*What is View State?
*Can you read the View State?
*What is the difference between encoding and encryption? Which is easy to break?
*Can we disable the view state application wide?
*can we disable it on page wide?
*can we disable it for a control?
*What is provider Model?
*Any idea of Data Access Component provided by Microsoft?
*Any idea of Enterprise library?
*What is web service?
*What is WSDL?
*Can a web service be only developed in asp.ent?
*can we use multiple web services from a single application?
*can we call a web service asynchronously?
*Can a web service be used from a windows application?
*What do we need to deploy a web service?
*What is the significance of web.config?
*Can we have multiple web.config files in a sigle web project?
*Can we have more then one configuration file?
*Type of Authentications?
*Can we have multiple assemblies in a single web project?
*What is GAC?
*What is machine.config?
*What different types of session state Management we have in asp.net?
*What are cookies?
*What is Cache?
*What is AJAX?
*Is AJAX a language?
*What is the difference between syncronus and asyncronus?
*What is an Assembly?
*Can an assembly contains more then one classes?
*What is strong name?
*What is the difference b/w client and server side?
*What we need for the deployment of a asp.net we application?
*what is the purpose of IIS?
*Difference between http and https?
*what is purpose of aspnet_wp.exe ?
*what is an ISAPI filter?
*what do you mean by HTTP Handler?
*What is the purpose of Global.asax?
*What is the significance of Application_Start/Session_Start/Application_Error?
*What is the difference between the inline and code behind?
*what is side by side execution?
*can we have two different versions of dot net frameworks running on the same machine?
*What is CLR? Difference b/w CLR and JVM?
*What is CLI?
*What is CTS?
*What is .resx file meant for?
*Any idea of aspnet_regiis?
*Any idea of ASP NET State Service?
*Crystal report is only used for read only data and reporting purposes?
*We can add a crystal report in aspx page using two techniques, what are these?
*What is the difference between stroed procedure and stored function in SQL?
*Can we have an updateable view in SQL?
*What is connection pooling? how can we acheive that in asp.net?
*What is DataSet?
*What is the difference between typed and untyped dataset?
*What is the difference bewteen accessing the data throgh the dataset and datareader?

Thanks,
Happy Interviewing.

Salary Negotiation Interview question

Ok that’s what we all do it for money… not everyone. This is probably the weakest area for techno savvy guys. They are not good negotiators. I have seen so many guys at the first instance they will smile and say “NEGOTIABLE SIR”. So here are some points:-

• Do a study of what is the salary trend? For instance have some kind of baseline. For example what is the salary trend on number of year of experience? Discuss this with your friends out.
• Do not mention your expected salary on the resume?
• Let the employer first make the salary offer. Try to delay the salary discussion till the end.
• If they say what you expect?, come with a figure with a little higher end and say negotiable. Remember never say negotiable on something which you have aimed, HR guys will always bring it down. So negotiate on AIMED SALARY + some thing extra.
• The normal trend is that they look at your current salary and add a little it so that they can pull you in. Do your homework my salary is this much and I expect this much so whatever it is now I will not come below this.
• Do not be harsh during salary negotiations.
• It’s good to aim high. For instance I want 1 billion dollars / month but at the same time be realistic.
• Some companies have those hidden cost attached in salary clarify that rather to be surprised at the first salary package.
• Many of the companies add extra performance compensation in your basic which can be surprising at times. So have a detail break down. Best is to discuss on hand salary rather than gross.
• Talk with the employer in what frequency does the hike happen.
• Take everything in writing, go back to your house and have a look once with a cool head is the offer worth it of what your current employer is giving.
• Do not forget once you have job in hand you can come back to your current employer for negotiation so keep that thing in mind.
• Remember the worst part is cribbing after joining the company that your colleague is getting more. So be careful while interview negotiations or be sportive to be a good negotiator in the next interview.
• One very important thing is that the best negotiation ground is not the new company where you are going but the old company which you are leaving. So once you have offer on hand get back to your old employee and show them the offer and then make your next move. It’s my experience that negotiating with the old employer is easy than with the new one….Frankly if approached properly rarely any one will say no. Just do not be aggressive or egoistic that you have an offer on hand. Top of all some time some things are worth above money :-

JOB SATISFACTION. So whatever you negotiate if you think you can get JOB SATISFACTION aspect on higher grounds go for it. I think its worth more than money.

SQL Server Interview Questions

What is RDBMS?
Relational Data Base Management Systems (RDBMS) are database management systems that maintain data records and indices in tables. Relationships may be created and maintained across and among the data and tables. In a relational database, relationships between data items are expressed by means of tables. Interdependencies among these tables are expressed by data values rather than by pointers. This allows a high degree of data independence. An RDBMS has the capability to recombine the data items from different files, providing powerful tools for data usage.

What is normalization?



Database normalization is a data design and organization process applied to data structures based on rules that help build relational databases. In relational database design, the process of organizing data to minimize redundancy. Normalization usually involves dividing a database into two or more tables and defining relationships between the tables. The objective is to isolate data so that additions, deletions, and modifications of a field can be made in just one table and then propagated through the rest of the database via the defined relationships.

What are different normalization forms?

1NF: Eliminate Repeating Groups
Make a separate table for each set of related attributes, and give each table a primary key. Each field contains at most one value from its attribute domain.
2NF: Eliminate Redundant Data
If an attribute depends on only part of a multi-valued key, remove it to a separate table.
3NF: Eliminate Columns Not Dependent On Key
If attributes do not contribute to a description of the key, remove them to a separate table. All attributes must be directly dependent on the primary key
BCNF: Boyce-Codd Normal Form
If there are non-trivial dependencies between candidate key attributes, separate them out into distinct tables.
4NF: Isolate Independent Multiple Relationships
No table may contain two or more 1:n or n:m relationships that are not directly related.
5NF: Isolate Semantically Related Multiple Relationships
There may be practical constrains on information that justify separating logically related many-to-many relationships.
ONF: Optimal Normal Form
A model limited to only simple (elemental) facts, as expressed in Object Role Model notation.
DKNF: Domain-Key Normal Form
A model free from all modification anomalies.

Remember, these normalization guidelines are cumulative. For a database to be in 3NF, it must first fulfill all the criteria of a 2NF and 1NF database.

What is Stored Procedure?
A stored procedure is a named group of SQL statements that have been previously created and stored in the server database. Stored procedures accept input parameters so that a single procedure can be used over the network by several clients using different input data. And when the procedure is modified, all clients automatically get the new version. Stored procedures reduce network traffic and improve performance. Stored procedures can be used to help ensure the integrity of the database.
e.g. sp_helpdb, sp_renamedb, sp_depends etc.

What is Trigger?
A trigger is a SQL procedure that initiates an action when an event (INSERT, DELETE or UPDATE) occurs. Triggers are stored in and managed by the DBMS.Triggers are used to maintain the referential integrity of data by changing the data in a systematic fashion. A trigger cannot be called or executed; the DBMS automatically fires the trigger as a result of a data modification to the associated table. Triggers can be viewed as similar to stored procedures in that both consist of procedural logic that is stored at the database level. Stored procedures, however, are not event-drive and are not attached to a specific table as triggers are. Stored procedures are explicitly executed by invoking a CALL to the procedure while triggers are implicitly executed. In addition, triggers can also execute stored procedures.
Nested Trigger: A trigger can also contain INSERT, UPDATE and DELETE logic within itself, so when the trigger is fired because of data modification it can also cause another data modification, thereby firing another trigger. A trigger that contains data modification logic within itself is called a nested trigger.

What is View?
A simple view can be thought of as a subset of a table. It can be used for retrieving data, as well as updating or deleting rows. Rows updated or deleted in the view are updated or deleted in the table the view was created with. It should also be noted that as data in the original table changes, so does data in the view, as views are the way to look at part of the original table. The results of using a view are not permanently stored in the database. The data accessed through a view is actually constructed using standard T-SQL select command and can come from one to many different base tables or even other views.

What is Index?
An index is a physical structure containing pointers to the data. Indices are created in an existing table to locate rows more quickly and efficiently. It is possible to create an index on one or more columns of a table, and each index is given a name. The users cannot see the indexes, they are just used to speed up queries. Effective indexes are one of the best ways to improve performance in a database application. A table scan happens when there is no index available to help a query. In a table scan SQL Server examines every row in the table to satisfy the query results. Table scans are sometimes unavoidable, but on large tables, scans have a terrific impact on performance.

Clustered indexes define the physical sorting of a database table’s rows in the storage media. For this reason, each database table may have only one clustered index.
Non-clustered indexes are created outside of the database table and contain a sorted list of references to the table itself.

What is the difference between clustered and a non-clustered index?
A clustered index is a special type of index that reorders the way records in the table are physically stored. Therefore table can have only one clustered index. The leaf nodes of a clustered index contain the data pages.

A nonclustered 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 on disk. The leaf node of a nonclustered index does not consist of the data pages. Instead, the leaf nodes contain index rows.

What are the different index configurations a table can have?
A table can have one of the following index configurations:

No indexes
A clustered index
A clustered index and many nonclustered indexes
A nonclustered index
Many nonclustered indexes

What is cursors?
Cursor is a database object used by applications to manipulate data in a set on a row-by-row basis, instead of the typical SQL commands that operate on all the rows in the set at one time.

In order to work with a cursor we need to perform some steps in the following order:

Declare cursor
Open cursor
Fetch row from the cursor
Process fetched row
Close cursor
Deallocate cursor

What is the use of DBCC commands?
DBCC stands for database consistency checker. We use these commands to check the consistency of the databases, i.e., maintenance, validation task and status checks.
E.g. DBCC CHECKDB - Ensures that tables in the db and the indexes are correctly linked.
DBCC CHECKALLOC - To check that all pages in a db are correctly allocated.
DBCC CHECKFILEGROUP - Checks all tables file group for any damage.

What is a Linked Server?
Linked Servers is a concept in SQL Server by which we can add other SQL Server to a Group and query both the SQL Server dbs using T-SQL Statements. With a linked server, you can create very clean, easy to follow, SQL statements that allow remote data to be retrieved, joined and combined with local data.
Storped Procedure sp_addlinkedserver, sp_addlinkedsrvlogin will be used add new Linked Server.

What is Collation?
Collation refers to a set of rules that determine how data is sorted and compared. Character data is sorted using rules that define the correct character sequence, with options for specifying case-sensitivity, accent marks, kana character types and character width.

What are different type of Collation Sensitivity?
Case sensitivity
A and a, B and b, etc.

Accent sensitivity
a and á, o and ó, etc.

Kana Sensitivity
When Japanese kana characters Hiragana and Katakana are treated differently, it is called Kana sensitive.

Width sensitivity
When a single-byte character (half-width) and the same character when represented as a double-byte character (full-width) are treated differently then it is width sensitive.

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 nonclustered index by default. Another major difference is that, primary key doesn’t allow NULLs, but unique key allows one NULL only.

How to 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.

What is a NOLOCK?
Using the NOLOCK query optimiser hint is generally considered good practice in order to improve concurrency on a busy system. When the NOLOCK hint is included in a SELECT statement, no locks are taken when data is read. The result is a Dirty Read, which means that another process could be updating the data at the exact time you are reading it. There are no guarantees that your query will retrieve the most recent data. The advantage to performance is that your reading of data will not block updates from taking place, and updates will not block your reading of data. SELECT statements take Shared (Read) locks. This means that multiple SELECT statements are allowed simultaneous access, but other processes are blocked from modifying the data. The updates will queue until all the reads have completed, and reads requested after the update will wait for the updates to complete. The result to your system is delay(blocking).

What is difference between DELETE & TRUNCATE commands?
Delete command removes the rows from a table based on the condition that we provide with a WHERE clause. Truncate will actually remove all the rows from a table and there will be no data in the table after we run the truncate command.

TRUNCATE
TRUNCATE is faster and uses fewer system and transaction log resources than DELETE.
TRUNCATE removes the data by deallocating the data pages used to store the table’s data, and only the page deallocations are recorded in the transaction log.
TRUNCATE removes all rows from a table, but the table structure and its columns, constraints, indexes and so on remain. The counter used by an identity for new rows is reset to the seed for the column.
You cannot use TRUNCATE TABLE on a table referenced by a FOREIGN KEY constraint.
Because TRUNCATE TABLE is not logged, it cannot activate a trigger.
TRUNCATE can not be Rolled back using logs.
TRUNCATE is DDL Command.
TRUNCATE Resets identity of the table.

DELETE
DELETE removes rows one at a time and records an entry in the transaction log for each deleted row.
If you want to retain the identity counter, use DELETE instead. If you want to remove table definition and its data, use the DROP TABLE statement.
DELETE Can be used with or without a WHERE clause
DELETE Activates Triggers.
DELETE Can be Rolled back using logs.
DELETE is DML Command.
DELETE does not reset identity of the table.

Difference between Function and Stored Procedure?
UDF can be used in the SQL statements anywhere in the WHERE/HAVING/SELECT section where as Stored procedures cannot be.
UDFs that return tables can be treated as another rowset. This can be used in JOINs with other tables.
Inline UDF’s can be though of as views that take parameters and can be used in JOINs and other Rowset operations.

When is the use of UPDATE_STATISTICS command?
This command is basically used when a large processing of data has occurred. If a large amount of deletions any modification or Bulk Copy into the tables has occurred, it has to update the indexes to take these changes into account. UPDATE_STATISTICS updates the indexes on these tables accordingly.

What types of Joins are possible with Sql Server?
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, CROSS JOINs. OUTER JOINs are further classified as LEFT OUTER JOINS, RIGHT OUTER JOINS and FULL OUTER JOINS.

What is the difference between a HAVING CLAUSE and a WHERE CLAUSE?
Specifies a search condition for a group or an aggregate. HAVING can be used only with the SELECT statement. HAVING is typically used in a GROUP BY clause. When GROUP BY is not used, HAVING behaves like a WHERE clause. Having Clause is basically used only with the GROUP BY function in a query. WHERE Clause is applied to each row before they are part of the GROUP BY function in a query. HAVING criteria is applied after the the grouping of rows has occurred.

What is sub-query? Explain properties of sub-query.
Sub-queries are often referred to as sub-selects, as they allow a SELECT statement to be executed arbitrarily within the body of another SQL statement. A sub-query is executed by enclosing it in a set of parentheses. Sub-queries are generally used to return a single row as an atomic value, though they may be used to compare values against multiple rows with the IN keyword.

A subquery is a SELECT statement that is nested within another T-SQL statement. A subquery SELECT statement if executed independently of the T-SQL statement, in which it is nested, will return a result set. Meaning a subquery SELECT statement can standalone and is not depended on the statement in which it is nested. A subquery SELECT statement can return any number of values, and can be found in, the column list of a SELECT statement, a FROM, GROUP BY, HAVING, and/or ORDER BY clauses of a T-SQL statement. A Subquery can also be used as a parameter to a function call. Basically a subquery can be used anywhere an expression can be used.

Properties of Sub-Query
A subquery must be enclosed in the parenthesis.
A subquery must be put in the right hand of the comparison operator, and
A subquery cannot contain a ORDER-BY clause.
A query can contain more than one sub-queries.

What are types of sub-queries?
Single-row subquery, where the subquery returns only one row.
Multiple-row subquery, where the subquery returns multiple rows,.and
Multiple column subquery, where the subquery returns multiple columns.

What is SQL Profiler?
SQL Profiler is a graphical tool that allows system administrators to monitor events in an instance of Microsoft SQL Server. You can capture and save data about each event to a file or SQL Server table to analyze later. For example, you can monitor a production environment to see which stored procedures are hampering performance by executing too slowly.

Use SQL Profiler to monitor only the events in which you are interested. If traces are becoming too large, you can filter them based on the information you want, so that only a subset of the event data is collected. Monitoring too many events adds overhead to the server and the monitoring process and can cause the trace file or trace table to grow very large, especially when the monitoring process takes place over a long period of time.

What is User Defined Functions?
User-Defined Functions allow to define its own T-SQL functions that can accept 0 or more parameters and return a single scalar data value or a table data type.

What kind of User-Defined Functions can be created?
There are three types of User-Defined functions in SQL Server 2000 and they are Scalar, Inline Table-Valued and Multi-statement Table-valued.

Scalar User-Defined Function
A Scalar user-defined function returns one of the scalar data types. Text, ntext, image and timestamp data types are not supported. These are the type of user-defined functions that most developers are used to in other programming languages. You pass in 0 to many parameters and you get a return value.

Inline Table-Value User-Defined Function
An Inline Table-Value user-defined function returns a table data type and is an exceptional alternative to a view as the user-defined function can pass parameters into a T-SQL select command and in essence provide us with a parameterized, non-updateable view of the underlying tables.

Multi-statement Table-Value User-Defined Function
A Multi-Statement Table-Value user-defined function returns a table and is also an exceptional alternative to a view as the function can support multiple T-SQL statements to build the final result where the view is limited to a single SELECT statement. Also, the ability to pass parameters into a T-SQL select command or a group of them gives us the capability to in essence create a parameterized, non-updateable view of the data in the underlying tables. Within the create function command you must define the table structure that is being returned. After creating this type of user-defined function, It can be used in the FROM clause of a T-SQL command unlike the behavior found when using a stored procedure which can also return record sets.

Which TCP/IP port does SQL Server run on? How can it be changed?
SQL Server runs on port 1433. It can be changed from the Network Utility TCP/IP properties –> Port number.both on client and the server.

What are the authentication modes in SQL Server? How can it be changed?
Windows mode and mixed mode (SQL & Windows).

To change authentication mode in SQL Server click Start, Programs, Microsoft SQL Server and click SQL Enterprise Manager to run SQL Enterprise Manager from the Microsoft SQL Server program group. Select the server then from the Tools menu select SQL Server Configuration Properties, and choose the Security page.

Where are SQL server users names and passwords are stored in sql server?
They get stored in master db in the sysxlogins table.

Which command using Query Analyzer will give you the version of SQL server and operating system?

SELECT  SERVERPROPERTY('productversion'), SERVERPROPERTY ('productlevel'), SERVERPROPERTY ('edition')

What is SQL server agent?
SQL Server agent plays an important role in the day-to-day tasks of a database administrator (DBA). It is often overlooked as one of the main tools for SQL Server management. Its purpose is to ease the implementation of tasks for the DBA, with its full-function scheduling engine, which allows you to schedule your own jobs and scripts.

Can a stored procedure call itself or recursive stored procedure? How many level SP nesting possible?
Yes. Because Transact-SQL supports recursion, you can write stored procedures that call themselves. Recursion can be defined as a method of problem solving wherein the solution is arrived at by repetitively applying it to subsets of the problem. A common application of recursive logic is to perform numeric computations that lend themselves to repetitive evaluation by the same processing steps. Stored procedures are nested when one stored procedure calls another or executes managed code by referencing a CLR routine, type, or aggregate. You can nest stored procedures and managed code references up to 32 levels.

What is @@ERROR?
The @@ERROR automatic variable returns the error code of the last Transact-SQL statement. If there was no error, @@ERROR returns zero. Because @@ERROR is reset after each Transact-SQL statement, it must be saved to a variable if it is needed to process it further after checking it.

What is Raiseerror?
Stored procedures report errors to client applications via the RAISERROR command. RAISERROR doesn’t change the flow of a procedure; it merely displays an error message, sets the @@ERROR automatic variable, and optionally writes the message to the SQL Server error log and the NT application event log.

What is log shipping?
Log shipping is the process of automating the backup of database and transaction log files on a production SQL server, and then restoring them onto a standby server. Enterprise Editions only supports log shipping. In log shipping the transactional log file from one server is automatically updated into the backup database on the other server. If one server fails, the other server will have the same db can be used this as the Disaster Recovery plan. The key feature of log shipping is that is will automatically backup transaction logs throughout the day and automatically restore them on the standby server at defined interval.

What is the difference between a local and a global variable?
A local temporary table exists only for the duration of a connection or, if defined inside a compound statement, for the duration of the compound statement.

A global temporary table remains in the database permanently, but the rows exist only within a given connection. When connection are closed, the data in the global temporary table disappears. However, the table definition remains with the database for access when database is opened next time.

What command do we use to rename a db?
sp_renamedb ‘oldname’ , ‘newname’
If someone is using db it will not accept sp_renmaedb. In that case first bring db to single user using sp_dboptions. Use sp_renamedb to rename database. Use sp_dboptions to bring database to multi user mode.

What is sp_configure commands and set commands?
Use sp_configure to display or change server-level settings. To change database-level settings, use ALTER DATABASE. To change settings that affect only the current user session, use the SET statement.

What are the different types of replication? Explain.
The SQL Server 2000-supported replication types are as follows:

• Transactional
• Snapshot
• Merge

Snapshot replication distributes data exactly as it appears at a specific moment in time and does not monitor for updates to the data. Snapshot replication is best used as a method for replicating data that changes infrequently or where the most up-to-date values (low latency) are not a requirement. When synchronization occurs, the entire snapshot is generated and sent to Subscribers.

Transactional replication, an initial snapshot of data is applied at Subscribers, and then when data modifications are made at the Publisher, the individual transactions are captured and propagated to Subscribers.

Merge replication is the process of distributing data from Publisher to Subscribers, allowing the Publisher and Subscribers to make updates while connected or disconnected, and then merging the updates between sites when they are connected.

What are the OS services that the SQL Server installation adds?
MS SQL SERVER SERVICE, SQL AGENT SERVICE, DTC (Distribution transac co-ordinator)

What are three SQL keywords used to change or set someone’s permissions?
GRANT, DENY, and REVOKE.

What does it mean to have quoted_identifier on? What are the implications of having it off?
When SET QUOTED_IDENTIFIER is ON, identifiers can be delimited by double quotation marks, and literals must be delimited by single quotation marks. When SET QUOTED_IDENTIFIER is OFF, identifiers cannot be quoted and must follow all Transact-SQL rules for identifiers.

What is the STUFF function and how does it differ from the REPLACE function?
STUFF function to overwrite existing characters. Using this syntax, STUFF(string_expression, start, length, replacement_characters), string_expression is the string that will have characters substituted, start is the starting position, length is the number of characters in the string that are substituted, and replacement_characters are the new characters interjected into the string.
REPLACE function to replace existing characters of all occurance. Using this syntax REPLACE(string_expression, search_string, replacement_string), where every incidence of search_string found in the string_expression will be replaced with replacement_string.

Using query analyzer, name 3 ways to get an accurate count of the number of records in a table?
SELECT * FROM table1
SELECT COUNT(*) FROM table1
SELECT rows FROM sysindexes WHERE id = OBJECT_ID(table1) AND indid <>

How to rebuild Master Database?
Shutdown Microsoft SQL Server 2000, and then run Rebuildm.exe. This is located in the Program Files\Microsoft SQL Server\80\Tools\Binn directory.
In the Rebuild Master dialog box, click Browse.
In the Browse for Folder dialog box, select the \Data folder on the SQL Server 2000 compact disc or in the shared network directory from which SQL Server 2000 was installed, and then click OK.
Click Settings. In the Collation Settings dialog box, verify or change settings used for the master database and all other databases.
Initially, the default collation settings are shown, but these may not match the collation selected during setup. You can select the same settings used during setup or select new collation settings. When done, click OK.
In the Rebuild Master dialog box, click Rebuild to start the process.
The Rebuild Master utility reinstalls the master database.
To continue, you may need to stop a server that is running.
Source: http://msdn2.microsoft.com/en-us/library/aa197950(SQL.80).aspx

What is the basic functions for master, msdb, model, tempdb databases?
The Master database holds information for all databases located on the SQL Server instance and is the glue that holds the engine together. Because SQL Server cannot start without a functioning master database, you must administer this database with care.
The msdb database stores information regarding database backups, SQL Agent information, DTS packages, SQL Server jobs, and some replication information such as for log shipping.
The tempdb holds temporary objects such as global and local temporary tables and stored procedures.
The model is essentially a template database used in the creation of any new user database created in the instance.

What are primary keys and foreign keys?
Primary keys are the unique identifiers for each row. They must contain unique values and cannot be null. Due to their importance in relational databases, Primary keys are the most fundamental of all keys and constraints. A table can have only one Primary key.
Foreign keys are both a method of ensuring data integrity and a manifestation of the relationship between tables.

What is data integrity? Explain constraints?
Data integrity is an important feature in SQL Server. When used properly, it ensures that data is accurate, correct, and valid. It also acts as a trap for otherwise undetectable bugs within applications.
A PRIMARY KEY constraint is a unique identifier for a row within a database table. Every table should have a primary key constraint to uniquely identify each row and only one primary key constraint can be created for each table. The primary key constraints are used to enforce entity integrity.

A UNIQUE constraint enforces the uniqueness of the values in a set of columns, so no duplicate values are entered. The unique key constraints are used to enforce entity integrity as the primary key constraints.

A FOREIGN KEY constraint prevents any actions that would destroy links between tables with the corresponding data values. A foreign key in one table points to a primary key in another table. Foreign keys prevent actions that would leave rows with foreign key values when there are no primary keys with that value. The foreign key constraints are used to enforce referential integrity.

A CHECK constraint is used to limit the values that can be placed in a column. The check constraints are used to enforce domain integrity.

A NOT NULL constraint enforces that the column will not accept null values. The not null constraints are used to enforce domain integrity, as the check constraints.

What are the properties of the Relational tables?
Relational tables have six properties:

• Values are atomic.
• Column values are of the same kind.
• Each row is unique.
• The sequence of columns is insignificant.
• The sequence of rows is insignificant.
• Each column must have a unique name.

What is De-normalization?
De-normalization is the process of attempting to optimize the performance of a database by adding redundant data. It is sometimes necessary because current DBMSs implement the relational model poorly. A true relational DBMS would allow for a fully normalized database at the logical level, while providing physical storage of data that is tuned for high performance. De-normalization is a technique to move from higher to lower normal forms of database modeling in order to speed up database access.

How to get @@error and @@rowcount at the same time?
If @@Rowcount is checked after Error checking statement then it will have 0 as the value of @@Recordcount as it would have been reset.
And if @@Recordcount is checked before the error-checking statement then @@Error would get reset. To get @@error and @@rowcount at the same time do both in same statement and store them in local variable. SELECT @RC = @@ROWCOUNT, @ER = @@ERROR

What is Identity?
Identity (or AutoNumber) is a column that automatically generates numeric values. A start and increment value can be set, but most DBA leave these at 1. A GUID column also generates numbers, the value of this cannot be controled. Identity/GUID columns do not need to be indexed.

What is a Scheduled Jobs or What is a Scheduled Tasks?
Scheduled tasks let user automate processes that run on regular or predictable cycles. User can schedule administrative tasks, such as cube processing, to run during times of slow business activity. User can also determine the order in which tasks run by creating job steps within a SQL Server Agent job. E.g. Back up database, Update Stats of Tables. Job steps give user control over flow of execution. If one job fails, user can configure SQL Server Agent to continue to run the remaining tasks or to stop execution.

What is a table called, if it does not have neither Cluster nor Non-cluster Index? What is it used for?
Unindexed table or Heap. Microsoft Press Books and Book On Line (BOL) refers it as Heap.
A heap is a table that does not have a clustered index and, therefore, the pages are not linked by pointers. The IAM pages are the only structures that link the pages in a table together.
Unindexed tables are good for fast storing of data. Many times it is better to drop all indexes from table and than do bulk of inserts and to restore those indexes after that.

What is BCP? When does it used?
BulkCopy is a tool used to copy huge amount of data from tables and views. BCP does not copy the structures same as source to destination.

How do you load large data to the SQL server database?
BulkCopy is a tool used to copy huge amount of data from tables. BULK INSERT command helps to Imports a data file into a database table or view in a user-specified format.

Can we rewrite subqueries into simple select statements or with joins?
Subqueries can often be re-written to use a standard outer join, resulting in faster performance. As we may know, an outer join uses the plus sign (+) operator to tell the database to return all non-matching rows with NULL values. Hence we combine the outer join with a NULL test in the WHERE clause to reproduce the result set without using a sub-query.

Can SQL Servers linked to other servers like Oracle?
SQL Server can be lined to any server provided it has OLE-DB provider from Microsoft to allow a link. E.g. Oracle has a OLE-DB provider for oracle that Microsoft provides to add it as linked server to SQL Server group.

How to know which index a table is using?
SELECT table_name,index_name FROM user_constraints

How to copy the tables, schema and views from one SQL server to another?
Microsoft SQL Server 2000 Data Transformation Services (DTS) is a set of graphical tools and programmable objects that lets user extract, transform, and consolidate data from disparate sources into single or multiple destinations.

What is Self Join?
This is a particular case when one table joins to itself, with one or two aliases to avoid confusion. A self join can be of any type, as long as the joined tables are the same. A self join is rather unique in that it involves a relationship with only one table. The common example is when company have a hierarchal reporting structure whereby one member of staff reports to another.

What is Cross Join?
A cross join that does not have a WHERE clause produces the Cartesian product of the tables involved in the join. The size of a Cartesian product result set is the number of rows in the first table multiplied by the number of rows in the second table. The common example is when company wants to combine each product with a pricing table to analyze each product at each price.

Which virtual table does a trigger use?
Inserted and Deleted.

List few advantages of Stored Procedure.

• Stored procedure can reduced network traffic and latency, boosting application performance.
• Stored procedure execution plans can be reused, staying cached in SQL Server’s memory, reducing server overhead.
• Stored procedures help promote code reuse.
• Stored procedures can encapsulate logic. You can change stored procedure code without affecting clients.
• Stored procedures provide better security to your data.

What is DataWarehousing?

• Subject-oriented, meaning that the data in the database is organized so that all the data elements relating to the same real-world event or object are linked together;
• Time-variant, meaning that the changes to the data in the database are tracked and recorded so that reports can be produced showing changes over time;
• Non-volatile, meaning that data in the database is never over-written or deleted, once committed, the data is static, read-only, but retained for future reporting;
• Integrated, meaning that the database contains data from most or all of an organization’s operational applications, and that this data is made consistent.

What is OLTP(OnLine Transaction Processing)?
In OLTP - online transaction processing systems relational database design use the discipline of data modeling and generally follow the Codd rules of data normalization in order to ensure absolute data integrity. Using these rules complex information is broken down into its most simple structures (a table) where all of the individual atomic level elements relate to each other and satisfy the normalization rules.

How do SQL server 2000 and XML linked? Can XML be used to access data?
FOR XML (ROW, AUTO, EXPLICIT)
You can execute SQL queries against existing relational databases to return results as XML rather than standard rowsets. These queries can be executed directly or from within stored procedures. To retrieve XML results, use the FOR XML clause of the SELECT statement and specify an XML mode of RAW, AUTO, or EXPLICIT.

OPENXML
OPENXML is a Transact-SQL keyword that provides a relational/rowset view over an in-memory XML document. OPENXML is a rowset provider similar to a table or a view. OPENXML provides a way to access XML data within the Transact-SQL context by transferring data from an XML document into the relational tables. Thus, OPENXML allows you to manage an XML document and its interaction with the relational environment.

What is an execution plan? When would you use it? How would you view the execution plan?
An execution plan is basically a road map that graphically or textually shows the data retrieval methods chosen by the SQL Server query optimizer for a stored procedure or ad-hoc query and is a very useful tool for a developer to understand the performance characteristics of a query or stored procedure since the plan is the one that SQL Server will place in its cache and use to execute the stored procedure or query. From within Query Analyzer is an option called “Show Execution Plan” (located on the Query drop-down menu). If this option is turned on it will display query execution plan in separate window when query is ran again.

C Interview Questions Interview question

1. Write a program in C to find the 3*3 matrix multiplication.

2. Write a program in C to find the complex number of a given number.

3. how to print all the combinations of a given integer.

4. what is the significance of following functions

• freopen()
• strtok()
• access()
• state()

5. what is the "escape hatch" provided by #pragma directive?

6. what is source code of this tringle ...
A
A N I
A N I R B
A N I R B A N
A N I R B A N P A
A N I R B A N P A U L

7. What happens when you overload the stack?

8. what do you mean by preprocessor directory?

9. What is byte offset of a field within a structure?

10. What is unabridged list?

11. How is structure passing and returning implemented?

12. Write sample code or algorithim to get all possible combinations of data that will be entered from keyboard.

13. Explian Floyd Cycle finding algorithm for circular link list?

14. Why is that a pointer is depicted by '*' in C?

15. Write a program to print an 2D array in spiral manner

16. #includevoid fun(int);void main(){ inta; a=3; fun(a); }void fun(int){ if(n>0) { fun(--n);...

17. Given the values of two nodes in a *binary search tree*, write a cprogram to find the lowest common ancestor.

18. Can we define an array without any constant expression? If Yes, How?

19. For what purpose pragma.h header file is used?

20. What is the advantage of zero filling in calloc() ?

Oracle Interview Questions - Part 13

1.What are the various types of Exceptions ?
User defined and Predefined Exceptions.

2.Can we define exceptions twice in same block ?
No.

3.What is the difference between a procedure and a function ?
Functions return a single variable by value whereas procedures do not return any variable by value. Rather they return multiple variables by passing variables by reference through their OUT parameter.

4.Can you have two functions with the same name in a PL/SQL block ?
Yes.

5.Can you have two stored functions with the same name ?
Yes.

6.Can you call a stored function in the constraint of a table ?
No.

7.What are the various types of parameter modes in a procedure ?
IN, OUT AND INOUT.

8.What is Over Loading and what are its restrictions ?
OverLoading means an object performing different functions depending upon the no. of parameters or the data type of the parameters passed to it.

9.Can functions be overloaded ?
Yes.

10.Can 2 functions have same name & input parameters but differ only by return datatype?
No.
11.What are the constructs of a procedure, function or a package ?
The constructs of a procedure, function or a package are : variables and constants cursors exceptions

12.Why Create or Replace and not Drop and recreate procedures ?
So that Grants are not dropped.

13.Can you pass parameters in packages ? How ?
Yes. You can pass parameters to procedures or functions in a package.

14.What are the parts of a database trigger ?
The parts of a trigger are:
A triggering event or statement
A trigger restriction
A trigger action

15.What are the various types of database triggers ?
There are 12 types of triggers, they are combination of :
Insert, Delete and Update Triggers.
Before and After Triggers.
Row and Statement Triggers.(3*2*2=12)

16.What is the advantage of a stored procedure over a database trigger ?
We have control over the firing of a stored procedure but we have no control over the firing of a trigger.

17.What is the maximum no. of statements that can be specified in a trigger statement ?
One.

18.Can views be specified in a trigger statement ?
No

19.What are the values of :new and :old in Insert/Delete/Update Triggers ?
INSERT : new = new value, old = NULL
DELETE : new = NULL, old = old value
UPDATE : new = new value, old = old value

20.What are cascading triggers? What is the maximum no of cascading triggers at a time?
When a statement in a trigger body causes another trigger to be fired, the triggers are said to be cascading. Max = 32.
21.What are mutating triggers ?
A trigger giving a SELECT on the table on which the trigger is written.

22.What are constraining triggers ?
A trigger giving an Insert / Update on a table having referential integrity constraint on the triggering table.

23.Describe Oracle database's physical and logical structure ?
Physical : Data files, Redo Log files, Control file.
Logical : Tables, Views, Tablespaces, etc.

24.Can you increase the size of a tablespace ? How ?
Yes, by adding datafiles to it.

25.Can you increase the size of datafiles ? How ?
No (for Oracle 7.0)Yes (for Oracle 7.3 by using the Resize clause ----- Confirm !!).

26.What is the use of Control files ?
Contains pointers to locations of various data files, redo log files, etc.

27.What is the use of Data Dictionary ?
Used by Oracle to store information about various physical and logical Oracle structures e.g. Tables, Tablespaces, datafiles, etc

28.What are the advantages of clusters ?
Access time reduced for joins.

29.What are the disadvantages of clusters ?
The time for Insert increases.

30.Can Long/Long RAW be clustered ?
No.
31.Can null keys be entered in cluster index, normal index ?
Yes.

32.Can Check constraint be used for self referential integrity ? How ?
Yes. In the CHECK condition for a column of a table, we can reference some other column of the same table and thus enforce self referential integrity.

33.What are the min. extents allocated to a rollback extent ?
Two

34.What are the states of a rollback segment ? What is the difference between partly available and needs recovery ?
The various states of a rollback segment are :ONLINE, OFFLINE, PARTLY AVAILABLE, NEEDS RECOVERY and INVALID.

35.What is the difference between unique key and primary key ?
Unique key can be null; Primary key cannot be null.

36.An insert statement followed by a create table statement followed by rollback ? Will the rows be inserted ?
Yes.

37.Can you define multiple savepoints ?
Yes.

38.Can you Rollback to any savepoint ?
Yes.

40.What is the maximum no. of columns a table can have ?
256.

Data Warehousing Interview Questions

1) What is source qualifier?
2) Difference between DSS & OLTP?
3) Explain grouped cross tab?
4) Hierarchy of DWH?
5) How many repositories can we create in Informatica?
6) What is surrogate key?
7) What is difference between Mapplet and reusable transformation?
8) What is aggregate awareness?
9) Explain reference cursor?
10) What are parallel querys and query hints?
11) DWH architecture?
12) What are cursors?
13) Advantages of de normalized data?
14) What is operational data source (ODS)?
15) What is meta data and system catalog?
16) What is factless fact schema?
17) What is confirmed dimension?
18) What is the capacity of power cube?
19) Difference between PowerPlay transformer and power play reports?
20) What is IQD file?
21) What is Cognos script editor?
22) What is difference macros and prompts?
23) What is power play plug in?
24) Which kind of index is preferred in DWH?
25) What is hash partition?
26) What is DTM session?
27) How can you define a transformation? What are different types of transformations in Informatica?
28) What is mapplet?
29) What is query panel?
30) What is a look up function? What is default transformation for the look up function?
31) What is difference between a connected look up and unconnected look up?
32) What is staging area?
33) What is data merging, data cleansing and sampling?
34) What is up date strategy and what are th options for update strategy?
35) OLAP architecture?
36) What is subject area?
37) Why do we use DSS database for OLAP tools?
38) What is a universe?
39) Analysis in business objects?
40) Who launches the supervisor product in BO for first time?
41) How can you check the universe?
42) What are universe parameters?
43) Types of universes in business objects?
44) What is security domain in BO?
45) Where will you find the address of repository in BO?
46) What is broad cast agent?
47) In BO 4.1 version what is the alternative name for broadcast agent?
48) What services the broadcast agent offers on the server side?
49) How can you access your repository with different user profiles?
50) How many built-in objects are created in BO repository?
51) What are alertors in BO?
52) What are different types of saving options in web intelligence?
53) What is batch processing in BO?
54) How can you first report in BO by using broadcast agent?
55) Can we take report on Excel in BO?

VB Interview Questions

• Why do you use Option Explicit?
• What are the commonly used data types in VBScript?
• What is a session object?
• What are the three objects of ADO?
• What are the lock-types available in ADO?
• Explain. What are the cursor types available in ADO? Explain.
• What is a COM component? How do you register a COM component?
• What is a virtual root and how do you create one?
• What is a database index, how do you create one, discuss its pros and cons?
• How do you use multiple record sets(rs.NextRecordSet)?
• As soon as you fetch a record set, what operations would you perform?
• Define a transaction.
• What are ACID properties of a transaction?
• How would you remotely administer IIS?
• What is RAID? What is it used for?
• What is normalization? Explain normalization types.
• What is the disadvantage of creating an index in every column of a database table?
• What are the uses of source control software?
• You have a query that runs slowly, how would you make it better?
• How would you make it better in .NET environment?
• What is a bit datatype? What is it used for?
• How would you go about securing IIS and MS-SQL Server?
• What is the difference between Request("field") and Request.Form("field")?
• What versions of VB have you used? Have you also used VBA or VBScript?
• Have you ever used classes? If so, how have you used them?
• Have you ever created ActiveX DLLs? If so, why did you create the DLLs instead of using code in the main application?
• Have you ever created ActiveX controls? If so, what did they do?
• Have you ever created ActiveX EXEs? If so, what were they used for?
• Have you ever used Collections? Collection Classes?
• Have you ever used ADO? DAO? RDO? Any other database engines?
• What database backends have you worked with? Access? SQL Server? Oracle?
• Have you ever used resource files? If so, for what reason?
• Have you used the FileSystemObject? The Dictionary Object? Regular Expressions?
• Have you developed COM+ components? Any other types of server based components?
• What source code control systems have you used?
• What versions of Windows have you used? Have you used any other operating systems?
• What third party ActiveX controls have you used?
• Are there any other programming tools, such as database diagramming, UML, or CASE tools, that you've used?
• Have you developed components for IIS? Developed ASP pages?
• If you were writing a program, what method would you use to send information from the main form of the application to a modal popup form and then pass any changes to the data back to the main form when the popup form was closed?
• How would you center a form on the screen? How about centering it on another form?
• If an event, such as a tool bar button or menu click,occurs on a MDI parent how can it invoke an action on one or more MDI child forms?
• What are some methods you can use to send data from one VB executable to another one?
• What are the differences between a standard module and a class module?
• What do you have to do to make your class visible to programs other than your own?
• How can you tell what kind of object an object variable is holding?
• Describe the different scopes of variables in VB.
• Describe the difference between a public variable in a form and one in a standard code module.
• How do you handle error conditions in your code?
• What are some uses and misuses of variants?
• What are some of the steps you can take to determine why your program is crashing with "Invalid Page Fault" errors?
• What are the different ways you can use threading in VB? When are they appropriate?
• How many tabs in a tabbed dialog do you consider appropriate?
• How many items should you make available to users in a listbox or combo box?
• What are the three main differences between flexgrid control and dbgrid(Data bound Grid) control
  The Microsoft FlexGrid (MSFlexGrid) control displays and operates on tabular data. It allows complete flexibility to sort, merge, and format tables containing strings and pictures. When bound to a Data control, MSFlexGrid displays read-only data.Adaptation to existing Visual Basic code for the data-bound grid (DBGrid).
  
  Dbgrid is A spreadsheet-like bound control that displays a series of rows and columns representing records and fields from a Recordset object.
  
  The data grids are bound controls; that is, they require a data source that actually connects to a database and retrieves their data. And it seems that the root of the problem with DBGrid is that there's no data source that can be readily included along with the DBGrid control.In Visual Basic, the solution is simply to include the Data Control on the same form as DBGrid. But the Data Control is an intrinsic control; it's unavailable to anything outside of the Visual Basic environment itself. and VB 6.0 has a new set of data controls (DataGrid, DataList, DataCombo, MSHFlexGrid, MSFlexGrid) that once again are bound controls. Unlike DBGrid, though, they support OLE DB, and therefore rely on the an ADO Data Source (and in particular the ActiveX Data Objects Data Control, or ADO DC) for data access. Unlike the Data Control, the ADODC is a custom control (that is, an .OCX) that can be added to any project. In short, if you add ADO DC to your project along with theDataGrid control.
  
• ActiveX and Types of ActiveX Components in VB ?
  Standard EXE
  ActiveX EXE
  ActiveX DLL
  ActiveX document
  ActiveX Control
  
• What is difference between inprocess and out of process ?
  An in-process component is implemented as a DLL, and runs in the same process space as its client app, enabling the most efficient communication between client and component.Each client app that uses the component starts a new instance of it.
  An out of process component is implemented as an EXE, and unlike a dll, runs in its own process space. As a result, exe's are slower then dll'sbecause communications between client and component must be marshalled across process boundaries. A single instance of an out of process component can service many clients.
  
• Advantage of ActiveX Dll over Active Exe ?
  
  ACTIVEX DLL:An in-process component, or ActiveX DLL, runs in another application’s process. In-process components are used by applications or other in-process components. this allows you to wrap up common functionality (like an ActiveX Exe).
  
  ACTIVEX EXE:An out-of-process component, or ActiveX EXE, runs in its own address space. The client is usually an application running in another process.The code running in an ActiveX Exe is running in a separate process space. You would usually use this in N-Tier programming.
  
  An ActiveX EXE runs out of process while an ActiveX DLL runs in the same process space as VB app. Also, and ActiveX EXE can be run independent of your application if desired.
• Explain single thread and multithread thread apartments.
  All components created with Visual Basic use the apartment model, whether they’re single-threaded or multithreaded. A single-threaded component has only one apartment, which contains all the objects the component provides.
  This means that a single-threaded DLL created with Visual Basic is safe to use with a multithreaded client. However, there’s a performance trade-off for this safety. Calls from all client threads except one are marshaled, just as if they were out-of-process calls.
  
• What is a Component?
  If you compile an ActiveX dll, it becomes a component.If you compile an ActiveX Control, it becomes both a component and a control.
  Component is a general term used to describe code that's grouped by functionality. More specifically, a component in COM terms is a compiled collection of properties/methods and events.
  Typically a component is loaded into your project via the References whereas an ActiveX Control is loaded into your project via "components".
  
• What is meant by "Early Binding" and "Late Binding"? Which is better?
  Early binding and late binding refer to the method used to bind an interface's properties and methods to an object reference (variable). Early binding uses type library information at design time to reference procedures, while late binding handles this at run time. Late bindinghandles this by interrogating the reference before each call to insure that it supports a particular method. Since every call to a late boundobject actually requires two calls ("Do you do this?" followed by "Okay, do it then"), late binding is much less efficient than early binding. Except where early binding is not supported (ASP, scripting, etc.), late binding should only be used in very special cases.
  It is a common misconception that any code using the CreateObject function instead of
  Set = New is using late binding. This is not the case. The type declaration of the object variable determines whetherit is late or early bound, as in the following:
  
  Dim A As Foo
  Dim B As Foo
  Dim C As Object
  Dim D As Object
  Set A = New Foo 'Early Bound
  Set B = CreateObject("FooLib.Foo") 'Early Bound
  Set C = CreateObject("FooLib.Foo") 'Late Bound
  Set D = New Foo 'Late Bound