what is Constraint? How many types of constraints in SQL ?

Answer Posted / mohan

Constraint is nothing but set of rules or restrictions on a column,in order to achieve business requirements.

There are five types of constraints,
they are
1.primary key
2.unique key
3.not null
4.check
5.foreign key

These constraints also called data integrity constraints.

Is This Answer Correct ?    0 Yes 1 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

What changes in the front end code is needed if mirroring is implemented for the high availability? : sql server database administration

782


How to connect php with different port numbers?

723


How to run sql server 2005 books online on your local system?

713


How each E-R model constructs can be mapped to the relational model?

722


Explain table valued parameters in sql server? Why tvp used?

731






What is a unique index?

674


what is hash nonclustered index

712


How do we upgrade from SQL Server 6.5 to 7.0 and 7.0 to 2000?

1789


How can you know if the row fetched from cursor is still valid in underlying table?

761


What is the datatype of rowid?

668


What is primary key, unique key, and foreign key?

726


Explain data warehousing in sql server?

774


How do I install only the client tools of sql server 2000?

734


what does the automatic recovery do? : Sql server administration

737


i have made a project i vb.net n created a .exe of it after installing it in to any pc, the database (sql express) is not geting accesed i.e the aplication cuts the link of the database, so plz help in this matter.

1578