Difference between primary key and unique key ?
Answer Posted / mareeswaran-jeyakani
The primary key cannot be accept the null values.The unique key can accept null values. assume that you have a two
columns column1 having primary key constraint and column2 having unique constraint if u try to insert null into column2 it will accept that values whereas column1 will not accept the null values.
THANK YOU.ALL THE BEST...............
Is This Answer Correct ? | 2 Yes | 2 No |
Post New Answer View All Answers
How to concatenate two text values in oracle?
State all possible different index configurations a table can possibly have?
How to invoke the data pump export utility?
Explain the different normalization forms?
How to define an anonymous block?
ABOUT IDENTITY?
how the Oracle Prepares the Execution Plan and how it chooses the Optimal one?
What is program global area (pga) in oracle?
What is the quickest way to fetch the data from a table?
Tab A A B ------ 1 A 2 B 3 C Tab B A B ----- 4 D 5 E 6 F Generate the value into B table from A table. Only table A has the value. Write the SQL query to get B table value.
Explain constraining triggers.
How to see free space of each tablespace?
How to drop an index?
What is meant by joins?
Explain what are clusters?