1.What is Transaction ?
Ans: A Transaction is a logical unit of work that comprises one or more SQL statements executed by a single user.
2.What is Read-Only Transaction ?
Ans: A Read-Only transaction ensures that the results of each query executed in the transaction are consistant with respect to the same point in time.
3.What is a deadlock ? Explain .
Ans: Two processes wating to update the rows of a table which are locked by the other process then deadlock arises. In a database environment this will often happen because of not issuing proper row lock commands. Poor design of front-end application may cause this situation and the performance of server will reduce drastically.
These locks will be released automatically when a commit/rollback operation performed or any one of this processes being killed externally
4.What do you mean by Live Lock?
Ans: A livelock is a single lock which is bassically work on the request for an exclusive lock is repeatedly denied because a series of overlapping shared locks keeps interfering. A livelock also occurs when read transactions monopolize a table or page, forcing a write transaction to wait indefinitely. When four denials are cmplete then SQL Server detects the situation and refuses further shared locks.
5.What is a cluster Key ?
Ans: The related columns of the tables are called the cluster key. The cluster key is indexed using a cluster index and its value is stored only once for multiple tables in the cluster.
6.What is Parallel Server ?
Ans: Multiple instances accessing the same database (Only In Multi-CPU environments)
7.What are the advantages of views?
Ans: 1.Provide an additional level of table security, by restricting access to a predetermined set of rows and columns of a table.
2.Hide data complexity.
3. Simplify commands for the user.
4.Present the data in a different perspective from that of the base table.
5.Store complex queries.
8.What are different types of Collation Sensitivity?
Ans: 1.Case sensitivity - A and a, B and b, etc.
2.Accent sensitivity
3.Kana Sensitivity - When Japanese kana characters Hiragana and Katakana are treated differently, it is called Kana sensitive.
4.Width sensitivity - A single-byte character (half-width) and the same character represented as a double-byte character (full-width) are treated differently than it is width sensitive.
9.When is the use of UPDATE_STATISTICS command?
Ans: 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.
10.What is the difference between a HAVING CLAUSE and a WHERE CLAUSE?
Ans: A Transaction is a logical unit of work that comprises one or more SQL statements executed by a single user.
2.What is Read-Only Transaction ?
Ans: A Read-Only transaction ensures that the results of each query executed in the transaction are consistant with respect to the same point in time.
3.What is a deadlock ? Explain .
Ans: Two processes wating to update the rows of a table which are locked by the other process then deadlock arises. In a database environment this will often happen because of not issuing proper row lock commands. Poor design of front-end application may cause this situation and the performance of server will reduce drastically.
These locks will be released automatically when a commit/rollback operation performed or any one of this processes being killed externally
4.What do you mean by Live Lock?
Ans: A livelock is a single lock which is bassically work on the request for an exclusive lock is repeatedly denied because a series of overlapping shared locks keeps interfering. A livelock also occurs when read transactions monopolize a table or page, forcing a write transaction to wait indefinitely. When four denials are cmplete then SQL Server detects the situation and refuses further shared locks.
5.What is a cluster Key ?
Ans: The related columns of the tables are called the cluster key. The cluster key is indexed using a cluster index and its value is stored only once for multiple tables in the cluster.
6.What is Parallel Server ?
Ans: Multiple instances accessing the same database (Only In Multi-CPU environments)
7.What are the advantages of views?
Ans: 1.Provide an additional level of table security, by restricting access to a predetermined set of rows and columns of a table.
2.Hide data complexity.
3. Simplify commands for the user.
4.Present the data in a different perspective from that of the base table.
5.Store complex queries.
8.What are different types of Collation Sensitivity?
Ans: 1.Case sensitivity - A and a, B and b, etc.
2.Accent sensitivity
3.Kana Sensitivity - When Japanese kana characters Hiragana and Katakana are treated differently, it is called Kana sensitive.
4.Width sensitivity - A single-byte character (half-width) and the same character represented as a double-byte character (full-width) are treated differently than it is width sensitive.
9.When is the use of UPDATE_STATISTICS command?
Ans: 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.
10.What is the difference between a HAVING CLAUSE and a WHERE CLAUSE?
Ans: They specify a search condition for a group or an aggregate. But the difference is that 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 whereas WHERE Clause is applied to each row before they are part of the GROUP BY function in a query
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