How to create a table with a field value decomposed from 2 fields in the same table ?

Question

0.00/5 (No votes)

See more:

Here what i want to do :

if u have a table containing information abt subscribers and that table got the following fields (example in Canda , subscriber number = 514 - XXXXXXX):

1- prefix ( refers to Operator id , foreign key to different table containing the id , the corresponding prefix and description of that id , EX: 1,514,CanadaPhone)

2- number ( rest of subscriber number as in canda Ex= XXXXXXX)

what i want a third field in that table which contains the subscriber_id combined from prefix and number but i want it to be done automatically .

if u change prefix the subscriber id will be changed and if u change the number the subscriber id will be changed AUTOMATICALLY

remember that i want that subscriber id to be the primary key to the table.

is it applicable or not ?
if it is applicable plz help me .

thnx in advance

Posted 29-May-10 23:52pm

KaRaMiLo

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Sandeep Mewara · Accepted Answer · 2010-05-30T04:54:00

What you need is a TRIGGER.

Read this: MSDN: SQL CREATE TRIGGER[^]

You can use trigger to automatically insert the third coloumn value as column 1 & 2 concatenated value.

Though, from DB design point of view (looking at Data Normalization[^]), you should avoid doing such thing. If needed at any time, while retriving you can concatenate the column values.