Data Base Key

Data Base Management System

Key
Primary key
candidate key
Foreign key
Alternate key
Composite key

Candidate key
Analtribute which is used to find a record unique is called candidate key

Primary key
A particulas identification of uniquerecord.a candidate key which is used to Find the primary.

Foreign key
Foreign key is a key in the child table which will rigene the primary key of the
Pasent table.

R No EX No Add Mak

Alternate key
Alternate key is a key which actas second primarykey.

Composite key
Combination of more than one attribute to primary key is called composite key.

LOB
LOB is called large object dataype. It is used to stone unstructced information
Ex:- videofiles,Audio files.upto 4 G.B
LOB types stone values, where are called locatores.
There are two types.
C 10B
B 10B
C10B: A column with a data type C10B is stonechas objects.