rajmanisha
Member • Jul 9, 2017
what is primary key?
what is primary key?
Howdy guest!
Dear guest, you must be logged-in to participate on CrazyEngineers. We would love to have you as a
member of our community. Consider creating an
account or login.
Replies
-
Administrator • Jul 9, 2017
How about adding a little more reference to your question? Are we talking about databases here?rajmanishawhat is primary key?Are you sure? This action cannot be undone. -
Member • Jul 9, 2017
#-Link-Snipped-#rajmanishawhat is primary key?Are you sure? This action cannot be undone. -
Member • Jul 10, 2017
In context of DBMS, primary key is a column in a table that uniquely identifies the rows of that table.Several rows of a table can have similar value for a column but in case if that column is a primary key for that table, it can't be same.
In addition to uniquely identifying a row, it also ensures that there cannot be any null value in that column(if it is the primary key for that table)
A simple example:
Here Roll No. column is the primary key of this table so values in that column cannot be same,but name and marks can have similar values.Are you sure? This action cannot be undone. -
Member • Aug 14, 2017
your aadhar number (Social security number ) in the US, Driving license number etc all can be your your primary key.rajmanishawhat is primary key?Are you sure? This action cannot be undone.