SQL - Oracle : Table Level and Column Level constraints

GeekInterview.com > Interview Questions > Oracle > SQL

Go To First | Previous Question | Next Question

SQL | Question 147 of 171

Oracle : Table Level and Column Level constraints

We have two type of constraints - Table Level and Column Level. Which is better and why..?

Total Answers and Comments: 6

Last Update: February 20, 2009 Asked by: Sant_parkash

Sponsored Links

Best Rated Answer

—

Submitted by: sampra

constraints are maiainly five
1.not null
2.unique
3primarykey
4.foreignkey
5.check
all colun level constarins only applited to table

Above answer was rated as good by the following members:
abhilashnanupillai

October 31, 2007 00:58:50

gemini burj

Member Since: October 2007 Contribution: 17

RE: Oracle : Table Level and Column Level constraints

Dear

If the same constraint is used in coloum leve or table leve then there is no difference in functanality i.e. if you are using primary key ore foreign key for the one column. This kind of constraint could be in table level or column leve and there will be no difference. But if you have to have a primary key and foreign key constraint for the multiple columns then you can not use this constraint in column level thse constraints are to be defined at table level.

Is this answer useful? Yes | No

February 14, 2008 05:06:58

safdar

Member Since: September 2007 Contribution: 5

RE: Oracle : Table Level and Column Level constraints

hi i am safdar dogar
in oracle there are five constraints
not null unique primary key check foreign key
not null always use in column level and foreign key always use in table lavel
but remaing three use column level and table level
both are working in same
am i right

Is this answer useful? Yes | No

1 0

Overall Rating: +1

February 25, 2008 05:44:07

gemini burj

Member Since: October 2007 Contribution: 17

RE: Oracle : Table Level and Column Level constraints

Dear

We have restrictions only for not null constraint that this can be sued at columns level only. even you can use foreign key constraint at colum level by using reference statement.

Is this answer useful? Yes | No

February 26, 2008 05:13:54

sampra

Member Since: February 2008 Contribution: 278

RE: Oracle : Table Level and Column Level constraints

constraints are maiainly five
1.not null
2.unique
3primarykey
4.foreignkey
5.check
all colun level constarins only applited to table

Is this answer useful? Yes | No

1 0

Overall Rating: +1

May 16, 2008 05:04:09

krishnaindia2007

Member Since: September 2007 Contribution: 854

RE: Oracle : Table Level and Column Level constraints

>>We have two type of constraints - Table Level and Column Level. Which is better and why..?

Performance wise there will not be any difference between table level and column level constraints.

Generally we use table level constraint to define composit keys( Constraint on combination of columns). Except not null constraint remaining constraints cane be defined at table table or column level. Not null constraint must be declared as column level constraint only.

Is this answer useful? Yes | No

1 0

Overall Rating: +1

February 20, 2009 03:28:22

abhilashnanupillai

Member Since: February 2009 Contribution: 1

RE: Oracle : Table Level and Column Level constraints

Constrains are the key word along with create table command. Different type of table constraints are primary key not null unique etc.

Is this answer useful? Yes | No

Go To Top

User Name		Remember Me?
Password

Question Bank