Difference between primary key and unique key ?
Answer Posted / umapathy.r
The column holding the primary key constraint cannot accept
null values.whereas colum holding the unique constraint can
accept null values assume that t3 is a table with two
columns t1 having primary key constraint and t2 having
unique constraint if u try to insert null into t2 it will
accept that values whereas column t1 will not accept null
| Is This Answer Correct ? | 1164 Yes | 121 No |
Post New Answer View All Answers
What is SQL Tuning Advisor in Oracle?
What is a read only transaction in oracle?
How to create a new table in oracle?
What is translate in oracle?
Difference between oracle's plus (+) notation and ansi join notation?
What is the purpose of tables, private synonyms and public synonyms in Oracle?
What is data block in Oracle?
How can Oracle users be audited?
Differentiate between post-database commit and post-form commit?
How to create an oracle database?
What are the database administrators utilities available?
What operating systems are supported by oracle database 10g xe?
How to check the oracle tns settings?
What is an anonymous block?
What is the difference between a hot backup and a cold backup in oracle?