SQL Basic

SQL

1. What is Primary Key?

Primary keys are unique names of a table.
Primary keys are integer ids in a table rows.
Primary keys are unique identifiers for each row in a table.
None of the above.


2. which is not a constraint in below options?

Foreign Key
Unique
Varchar
All of the above


3. A column that automatically generates numeric values is called __________.

Unique column
Integer column
Identity column
Candidate column


4. Select which is not in Joins?

Inner Join
Outer Join
Primary Join
Cross Join


5. What are indexes?

Index speed up the data retrieval
Index stores large number of integer values
Index minimize the data redundancy
None of the above.


6. What is the difference between Primary key and Unique key?

Primary key doesn’t allow null value whereas unique key allows multiple null values
Primary key allows one null value whereas unique key doesn’t allow null value.
Primary key doesn’t allow null value whereas unique key allows one null value.
Primary key allows one null value whereas unique key allows multiple null values.


7. What is a trigger?

A trigger is a SQL procedure that initiates an action when event (INSERT, DELETE or UPDATE) occurs
A trigger is an event that can be raised from Stored Procedures.
A trigger is a SQL procedure that performs some tasks on accessing db tables.
A trigger is a procedure which executes when an error occurred.


8. How many types of indexes in SQL server?

Integer and string
Unique and non-unique
Clustered and Nonclustered
None of the above


9. What is View?

Virtual table
Physical table
It's not a virtual table
None of the above


10. what is Order by ?

It will arrange in asecnding/ descending order
It won't arrange in asecnding/ descending order
It will join the tables
None of the above