Tag: databases

Questions Related to databases

Implicit cursors are declared for
technology databases

  1. Some DML,PL/SQL statements

  2. All DML,PL/SQL statements

  3. Only PL/SQL statements

  4. None of the Above

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Correct Option: B

For processing rows in a specific sequence,
technology databases

  1. Use ORDER BY clause

  2. Use ROW clause

  3. Use ROW BY clause

  4. None of the Above

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Correct Option: A

What is true about triggers I. instead of trigger can be used on tables and views 2. instead of trigger can fire at eah row and statement levels. 3. Compund trigger in 10g allows us to specify multiple timig events on single database objects. 4. we should not use the same object which fired the trigger inside the trigger. this will result in mutating trigger error.
technology databases

  1. 2 and 4 are true

  2. 1 , 3 and 4 are true

  3. 1 and 3 are true

  4. Only 4 is true

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Correct Option: D

For which constraints are indexes created when the constraint is added?
technology databases

  1. Check

  2. Unique

  3. Primary key

  4. not null

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Correct Option: B,C

What is the difference between Union and Union all statements
technology databases

  1. Union all used for combining multiples queries using single union all

  2. There is no difference

  3. the union will eliminate duplicate records in result set but, union all will print the duplicate records

  4. Union all is used for select with multiple columns

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Correct Option: C

what is true about Delete and truncate 1. Truncate can not be used in PL/SQL 2. Delete will remove the data and will not move watermark. 3. Both statements require commit 4. truncate can remove selected records
technology databases

  1. 1 and 2 are correct

  2. All are true

  3. 1,2 and 3 are correct

  4. 2,3 and 4 are correct

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Correct Option: A

What is the default value for the OPTIMIZER_MODE initialization parameter?
technology databases

  1. FIRST_ROWS

  2. ALL_ROWS

  3. CHOOSE

  4. COST

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Correct Option: C

Can we have multiple primary keys in a table?
technology databases

  1. True

  2. False

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Correct Option: B

Which are the aggregate functions?
technology databases

  1. SUM

  2. AVG

  3. trim

  4. median

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Correct Option: A,B,D

We have unique constraint on sal column on emp table. can the column accept multiple null values?
technology databases

  1. True

  2. False

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Correct Option: A