Tag: databases

Questions Related to databases

How to see the time of execution of an SQL Statement.
technology databases

  1. set timing on select * from EMP

  2. set time on select * from EMP

  3. time on select * from EMP

  4. set timings on select * from EMP

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Correct Option: A

What is the Datatype of NULL in Oracle?
technology databases

  1. Long

  2. Int(0)

  3. Char(0)

  4. Binary

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Correct Option: C

what is the maximum length of all Oracle Objects?
technology databases

  1. <=30 characters

  2. <=40 characters

  3. <=32 characters

  4. <=20 characters

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Correct Option: A

In Oracle can we do any DMLs in a function which is called from a select statement?
technology databases

  1. True

  2. False

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Correct Option: B

In Oracle, is the following Anonymous block is valid? Declare Begin End;
technology databases

  1. True

  2. False

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Correct Option: B

In an Outer Join, what happens to columns that are not matched?
technology databases

  1. All matched columns returns NULLS.

  2. All unmatched columns returns NULLS.

  3. All matched and unmatched columns returns NULLS.

  4. Cant say

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Correct Option: B

User_Source table contains code for which all Objects?
technology databases

  1. Functions

  2. Package body

  3. Triggers

  4. Cursor

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Correct Option: A,B,C

For which of these constraints, an unique index is automatically created while creating constraints?
technology databases

  1. Foreign Key

  2. Primary Key

  3. Check

  4. Unique

  5. Not Null

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Correct Option: A,B,C,D,E

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

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Correct Option: D

What is the difference between varchar and varchar2 data types?
technology databases

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

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

  3. varchar data type is not supported in oracle

  4. varchar is applicable only to PL/SQL

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Correct Option: D