Tag: databases

Questions Related to databases

Select length(-1) from dual What is the output of the above sql stmt
technology databases

  1. 2

  2. 1

  3. 0

  4. error

Show answer
Correct Option: A

The standard EMP table contains 14 records corresponding to the employess of the corporation.One of those records has a NULL value stored in the MGR column.If Issue the following command on the table: select count(mgr) from emp; What is the count?
technology databases

  1. 14

  2. >14

  3. error

  4. <14

Show answer
Correct Option: D

You can declare this only by using table contraint syntax
technology databases

  1. Composite primarykey

  2. Not null

  3. unique

  4. check

Show answer
Correct Option: A

An interval literal specifies
technology databases

  1. a period of time

  2. a numerical difference

  3. a descriptive number

  4. a floating point number

Show answer
Correct Option: A

You use comments in a SQL statement to pass hints to the Oracle optimizer.
technology databases

  1. False

  2. This is hard to determine

  3. True

  4. None of the choices

Show answer
Correct Option: C

For each DATE value in an Oracle database, which of the following information is stored (choose all that apply):
technology databases

  1. second

  2. century

  3. hour

  4. year

  5. date

  6. month

Show answer
Correct Option: A,B,C,D,E,F

Which of the following are the correct value for the column whose data type is declared as number(3,4)
technology databases

  1. 123.21

  2. 0.001

  3. 0.01

  4. 123.01

Show answer
Correct Option: C

Which of the following describes the difference between varchar and varchar2 data types
technology databases

  1. varchar is used to store fixed length character data, varchar2 is for variable length character data

  2. varchar data type is not supported in oracle

  3. varchar data type is applicable only to PL/SQL

  4. maximum length for varchar is 2000 bytes and for varchar2 is 4000 bytes

Show answer
Correct Option: D

What is true in case of deferred constraints in Oracle?

technology databases

  1. The Constraint condition is never checked

  2. The Constraint condition is checked only at the time of commiting the transaction

  3. The Constraint condition is checked only for newly inserted rows and will not be checked for already existing rows in the table

  4. The constraint condition is checked after a predefined time interval

Show answer
Correct Option: B

Which of the following clause enables to drop the foreign key constraints of the child table while dropping the parent table?
technology databases

  1. drop foreign keys

  2. cascade constraints

  3. this is not possible in oracle

  4. clear references

Show answer
Correct Option: B