topic Re: primary keytable in Application Development and Automation Discussions

primary keytable

Former Member — Thu, 01 Mar 2007 06:41:15 GMT

hi experts,

what is primarykey table and forignkeytable?

thanks in advance

radhakrishna.

Re: primary keytable

Former Member — Thu, 01 Mar 2007 06:45:36 GMT

Hi,

Primary key : The field which is Unique and not null is called the Primary Key field

Foreign Key : To establish the relations between 2 tables the same key kield in another table is the Foreign key.

Foreign key can or can not be Unique and not-null.

Regards,

Anji

Re: primary keytable

p291102 — Thu, 01 Mar 2007 06:48:28 GMT

Hi,

I guess that the FOREIGN KEY constraint assures us that the referenced column is

a PRIMARY KEY in an another table.

You can reference any colums with the REFERENCE constraint on column.

Thanks,

Shankar

Re: primary keytable

Former Member — Thu, 01 Mar 2007 06:57:40 GMT

HI,

Primary key : The field which is Unique and not null is called the Primary Key field

Foreign Key : To establish the relations between 2 tables the same key kield in another table is the Foreign key.

Foreign key can or can not be Unique and not-null.

SRI

Re: primary keytable

Former Member — Thu, 01 Mar 2007 07:14:09 GMT

Hi Radhakrishanan,

<b>Primary Key:</b>

A primary key is usually called as an unique key.A primary key is defined for each database table. A user-defined primary key can consist of one or more columns.The primary key must have a unique value for each table row. The primary key is either defined by the database user, or generated internally.

<b>

Foreign key</b>

If the values in a column (or a combination of columns) of a table always match the values of the primary key column of another table, then this column (or combination of columns) is called a foreign key.

Please refer to the thread

Hope your query is resolved.

Thanks and regards,

Siva