What are constraints? Explain different types of
constraints?

Answer Posted / haritha

constraint is a rule which can not be voilated by end users.
Different types of constraints are available.They are:-
1)default constraint:-which is used to define a default
value.
2)primary key:-the key which does not allows duplication
and null values.
3)foreign key:-the key used to refer primary key defined
field in another table and it allows duplication.
4)null:-which allows NULL values.
5)not null:-which does not allows NULL values.
6)unique key:-which does not allows duplication but allows
NULL values.

Is This Answer Correct ?    283 Yes 70 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

Explain rdbms?

674


How many types of local tables are there in sql server?

572


Explain the properties of the relational tables?

629


Which are the new data types introduced in sql server 2008?

592


What is query cost in sql server?

646






When is update_statistics command used?

674


Can You Use A Stored Procedure To Provide Data To An Ssrs Report?

119


Why it is recommended to avoid referencing a floating point column in the where clause?

613


Why use triggers?

679


What gets stored inside msdb database?

844


Which Model uses the SET concept

667


How to connect a database with sql express.?

665


Explain the relational database management system (rdbms)?

635


How many types of triggers in sql server?

612


How to include text values in sql statements?

674