What is the diff. bwt. primary key and unique key?
Answers were Sorted based on User's Feedback
Answer / janhvee
diff. between primary key and unique is unique key can be
null but primary key can't be null.
one table can have only one primary key but unique key can
be multiple keys
| Is This Answer Correct ? | 17 Yes | 0 No |
Answer / rakesh ranjan
IN PRIMARY KEY IS ONLY IN ANY TABLE BUT WHEN WE TALKING
ABOUT UNIQUE KEY, IT CAN BE NULL.
| Is This Answer Correct ? | 5 Yes | 1 No |
primary is not allow null value.but unique can be allow null
value
| Is This Answer Correct ? | 3 Yes | 0 No |
Answer / sonu kumar
primary of any table can't be null but unique can be
primary key may be a unique key but unique can't be a primary key b/c primary key of any relation cant be a null value
| Is This Answer Correct ? | 0 Yes | 0 No |
How to create a new table by selecting rows from another table in mysql?
How do I connect to mysql database?
Why should I use mysql?
What is the maximum no of columns a table can have?
i made a table in sql server 2000 and in a column i want to add image path of a picture present in my hardisk... so using insert statement how will i insert the path of the image in the table??
How do I restore a database in mysql workbench?
What are the differences between binary and varbinary?
How do you shutdown a mysql database?
Write a query to retrieve a hundred books starting from 20th.
What are the indexes in mysql?
table a has records 1,1,1,1 table b has records 1,1,1,1,1,1 what would be out if perform join for all cases
Is postgresql better than mysql?
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)