Oracle constraints - August 28, 2008 at 15:00 PM by
Amit Satpute
Explain various types of constraints in Oracle.
Answer
Oracle "Check" Constraint:
It validates incoming columns at row insert time.
Not Null Constraint:
It is used to specify that a column may never contain a NULL value.
Primary Key Constraint:
It is used to identify the primary key for a table. This operation
requires that the primary columns are unique, and it creates a unique index on
the target primary key.
References Constraint:
This is the foreign key constraint and is only applied during INSERT and
DELETE.
Unique Constraint:
It is used to ensure that all column values within a table never
contain a duplicate entry.
Oracle constraints - Nov 17, 2008 at 15:00 PM by Nishant Kumar
What is an integrity constraint?
Answer - Integrity constraints define a business rule for a
column of the table. They are defined with a table and are stored as part of a
table’s definition.
Types of integrity constraints supported by oracle are
NOT NULL integrity constraint
Unique Key integrity constraint
Primary Key integrity constraint
Foreign key integrity constraint
Check integrity constraint
|