Pl/sql

[jenni]

What is the difference between unique key and primary key in PL/SQL ?

[chritzuk]

A common question. Read through this post and ye shall be enlightened ;)

[Link Removed]

[debasisdas]

Unique key and primary key are important in SQL .

Unique key is used to maintain uniqueness of data in a field.(no duplicate value)
Primay key follows the above ,along with that it ensurees data ia NOT NULL.(no duplicate value + data entry is compulsary)