gemini burj

 Profile Answers by gemini burj 

• Oct 31st, 2007

 

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.

safdar

 Profile Answers by safdar 

• Feb 14th, 2008

 

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

gemini burj

 Profile Answers by gemini burj 

• Feb 25th, 2008

 

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.

sampra

 Profile Answers by sampra 

• Feb 26th, 2008

 

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

krishnaindia2007

 Profile Answers by krishnaindia2007 

• May 16th, 2008

 

>>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.

abhilashnanupillai

 Profile Answers by abhilashnanupillai 

• Feb 20th, 2009

 

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

Mohit

• Oct 3rd, 2015

 

I think Table level contraints are imposed when we have to compare values in multiple columns,suppose delivery_date cannot be less than order_date..