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
When cursors are useful?
What is ms sql server triggers?
What is the difference between varchar and nvarchar datatypes?
What is the difference between lock, block and deadlock? : sql server database administration
Which are the new data types introduced in sql server 2008?
New concepts of sql server 2005 use in your project.
What is sql profiler. What are the default templates with it? : sql server database administration
What is the command used to check locks in microsoft sql server?
List out the different types of locks available in sql server?
Differentiate between ms sql server reporting services vs crystal reports?
How to insert multiple rows with a subquery?
What happens if an integer is too big for int date type?
How do I shrink an ldf file?
What specific conditions database should meet, before you can bulk copy data into it using bcp?
Explain different types of index?