topic Re: primary key in Application Development and Automation Discussions

primary key

Former Member — Thu, 21 Feb 2008 07:06:58 GMT

is there any diffrence between Primary key and primary Index

Re: primary key

Former Member — Thu, 21 Feb 2008 07:14:46 GMT

hi,

primary index is nothing but set of primary keys in a table through which we can search a table at faster rate.

thats it nothing more difference.

regards,

pavan t.

Edited by: Pavan T on Feb 21, 2008 8:15 AM

Re: primary key

Former Member — Thu, 21 Feb 2008 07:16:41 GMT

hi,

The primary index contains the key fields of the table and a pointer to the non-key fields of the table. The primary index is created automatically when the table is created in the database. that key fields may be primary key or foreign keys also.

where as Primary key we need create explicitly and if u make primary key for a particulear field it won't allow duplicate values for that field.

there won't be any difference as per my knowledge.

*if useful reward with points*

Edited by: subas Bose on Feb 21, 2008 8:17 AM

Re: primary key

Former Member — Thu, 21 Feb 2008 07:19:16 GMT

PRIMARY INDEX:

This is aumatically generated the movement we create a database table.It is only for the key fields in the table. The primary index contains the key fields of the table and a pointer to the non-key fields of the table. The primary index is created automatically when the table is created in the database.

PRIMARY KEY:

Primary key is mandatory.it avoid the duplicate of data.for ex (student rollno, material no, employee id)it should be a unique.

when you create the foreign key table . you want to refer only the primary key field of the reference table(checked table)

when you create the foreign key in the particular table before it should be one primary key. you can create no of primary keys in one table. by defaultly the one primary index should be created for that table.

Regards.