define primary key & secondary key?
Answers were Sorted based on User's Feedback
Answer / manoj
primary key is a key which always accept unique value.
secondary key is a key which when you are making primary key
for more than one column as primary key for retrieving of
reords.
eg.
create table tnam
(ano number,
bno number,
bname char(12),
primary key(ano,bno))
In this bno is secondary key.
| Is This Answer Correct ? | 31 Yes | 18 No |
Answer / renu kakkar
PRIMARY REPRESENTS THE ROW/TUPPLE UNIQUELY WHEREAS
SECONDARY KEY REPRESENTS THE SET OF TUPPLES
EMPLOY_ID IS A PRIMARY KEY AND EMPLOY_DEPTT. IS A SECONDARY
KEY.
| Is This Answer Correct ? | 3 Yes | 9 No |
Whate is use of MOD function in pl/sql.
Are subqueries better than joins?
explain advantages of myisam over innodb? : Sql dba
What is a pl/sql block?
What are functions in sql?
Is pl sql different from sql?
How can you fetch first 5 characters of the string?
Whis is not false in primary key?
what is self join and what is the requirement of self join? : Sql dba
Explain the purpose of %type and %rowtype data types with the example?
What is cold data?
Which column in the user.triggers data dictionary view shows that the trigger is a pl/sql trigger?
Oracle (3259)
SQL Server (4518)
MS Access (429)
MySQL (1402)
Postgre (483)
Sybase (267)
DB Architecture (141)
DB Administration (291)
DB Development (113)
SQL PLSQL (3330)
MongoDB (502)
IBM Informix (50)
Neo4j (82)
InfluxDB (0)
Apache CouchDB (44)
Firebird (5)
Database Management (1411)
Databases AllOther (288)