Tag: databases

Questions Related to databases

What will be the output of the query SELECT column FROM table ORDER BY column DESC LIMIT 7,10;
technology databases

  1. Would skip the first 7, and then get you the next ten highest.

  2. not a valid mysql query

  3. Would skip the first 10, and then get you the next 7 highest.

  4. None of the above

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Correct Option: A

Which Oracle access method is the fastest way for Oracle to retrieve a single row?

technology databases

  1. Primary key access

  2. Access via unique index

  3. Table access by ROWID

  4. Full table scan

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Correct Option: C

Which of the following can be a valid column name?

technology databases

  1. Column

  2. 1966_Invoices

  3. Catch_#22

  4. #Invoices

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Correct Option: C

Which command will delete all data from a table and will not write to the rollback segment?
technology databases

  1. DROP

  2. DELETE

  3. CASCADE

  4. TRUNCATE

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Correct Option: D

Which character function can be used to return a specified portion of a character string?
technology databases

  1. INSTR

  2. SUBSTRING

  3. SUBSTR

  4. POS

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Correct Option: C

When a user creates an object without a TABLESPACE clause, where will Oracle store the segment?

technology databases

  1. System tablespace

  2. Users tablespace

  3. Default tablespace for the user

  4. Oracle will give an error

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Correct Option: C

Which character is used to continue a statement in SQL*Plus?

technology databases

  1. *

  2. /

  3. -

  4. @

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Correct Option: C

What is the best way for a deadlock to be resolved?

technology databases

  1. All statements are removed and have to be resubmitted

  2. The Oracle server rolls back the statement that detected the deadlock

  3. The administrator has to kill the session

  4. Deadlocks can not be resolved

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Correct Option: B

When an executable SQL statement executes, a transaction begins. Which of the following events can NOT cause a transaction to end?

technology databases

  1. The user disconnects from Oracle

  2. A COMMIT or a ROLLBACK statement is used in conjunction with a SAVEPOINT clause

  3. A user process is terminated abnormally

  4. A DDL statement such as DROP, GRANT, RENAME

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Correct Option: B

Which dictionary view or views should be monitored to determine how long users are waiting for dispatchers?
technology databases

  1. V$SESSTAT

  2. V$QUEUE

  3. V$SHARED_SERVER

  4. V$VIEW

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Correct Option: B