what is Constraint? How many types of constraints in SQL ?
Answer Posted / bimaleswar patel
Constraints are used to limit the type of data that can go
into a table.
two basic types of constraints are there
1.column level
2.table level
the difference is that column level constraints are apply
only to one column where as table level constraints are
apply to whole table
Constraints are declare at the time of table creation using
CREATE TABLE command
there are 6 constraints used in oracle
1.NOT NULL
2.UNIQUE
3.PRIMARY KEY
4.CHECK
5.DEFAULT
6.REFERENCES
Is This Answer Correct ? | 96 Yes | 24 No |
Post New Answer View All Answers
What happens if null values are involved in boolean operations?
Mention the differences between substr and charindex in sql server.
How to write character string constants or literals in ms sql server?
What languages bi uses to achieve the goal?
What is Sqlpaging in SqlServer 2005 ?
What happens if you are trying to access a schema not owned by you?
What is difference between cte and view?
What is a trace frag?
what are the different types of SSRS reports?
What is the advantage of sql server?
What is a trigger what are the advantages of trigger?
If user is owning any SQL Objects, can we drop that user
How do you set a trace flag in sql server?
What does the on delete cascade option do?
What is difference between unique and primary key?