Tag: databases

Questions Related to databases

Two or more transactions in a simultaneous wait state, each waiting for other to release before it can proceed, is called
technology databases

  1. Lost Update

  2. uncommitted dependency

  3. infinite loop

  4. Deadlock

  5. With hold

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Correct Option: D

Which of the following is TRUE about Primary Key?
technology databases

  1. Same value of Primary Key can appear in more than one row in the table

  2. A Primary key defined column can be of type LONG

  3. A column that is defined as Primary Key cannot contain NULL value.

  4. Both A. and B.

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Correct Option: C

A table called EMPLOYEE has the following columns: name, department, and phone_number. Which of the following can limit read access to the phone_number column?
technology databases

  1. Using a view to access the table

  2. Using a referential constraint on the table

  3. Revoking access from the phone_number column

  4. Defining a table check constraint on the table

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Correct Option: A

Target table T1 is getting deleted. Table T2 has the foreign key. We require that whenever a row from T1 is deleted, the corresponding row from T2 also be deleted. Which option can be used?

technology databases

  1. ON DELETE RESTRICT

  2. ON DELETE CASCADE

  3. ON DELETE SET NULL

  4. ON DELETE CHILD

  5. ON DELETE MATCH

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Correct Option: B

DB2 WITH HOLD option What does WITH HOLD option do ?
technology databases

  1. forces cursor to close after commit

  2. Keeps cursor open after commit

  3. Does not allow cursor to close till all rows are fetched

  4. Locks the cursor

  5. None of the above

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Correct Option: B

The tables can be combined together in SQL using the concept of
technology databases

  1. Normalization

  2. Indexing

  3. Sequence

  4. Join

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Correct Option: D

If the value is null in order to place a value in it the function used is
technology databases

  1. Substitute( )

  2. Place value ( )

  3. NVL ( )

  4. Place( )

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Correct Option: C

Which of the following joins is possible in SQL
technology databases

  1. EQUI-JOIN

  2. NON EQUI-JOIN

  3. Both A. and B.

  4. None of the Above

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Correct Option: C

Unique numbers can be assigned to columns in a database using
technology databases

  1. Clusters

  2. Synonym

  3. Views

  4. Sequences

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Correct Option: D
Explanation:

To solve this question, the user needs to have a basic understanding of databases and the different methods used to assign unique numbers to columns in a database.

Now, let's go through each option and explain why it is right or wrong:

A. Clusters: Clusters are used to group related data together in a database. They are not used to assign unique numbers to columns in a database. Therefore, this option is incorrect.

B. Synonym: Synonyms are used to provide an alternative name for a table or view in a database. They are not used to assign unique numbers to columns in a database. Therefore, this option is incorrect.

C. Views: Views are virtual tables that are created by combining data from one or more tables in a database. They are not used to assign unique numbers to columns in a database. Therefore, this option is incorrect.

D. Sequences: Sequences are used to generate unique numbers for a column in a database. They are often used to assign primary keys to tables in a database. Therefore, this option is correct.

The Answer is: D

A table T1 having 100 rows is joined with a table T2 with 50 rows without specifying the joined column in the where clause then result will have
technology databases

  1. 100 rows

  2. 50 rows

  3. 150 rows

  4. 5000 rows

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Correct Option: D