How to prevent same user-id during a new user creation?

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ASP.NET

How to prevent same user-id insertion during a new user creation in asp.net?how will I do the checking from sqlserver?

Posted 24-Jul-12 1:17am

Saugata84

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StianSandberg 24-Jul-12 7:34am

I think you should be a little more precise here. What is "user-id" in your code? Is it a username or an increasing number?

3 solutions

Solution 1

Make the ID column of your table Primary Key[^]

SQL PRIMARY KEY Constraint[^]
-The PRIMARY KEY constraint uniquely identifies each record in a database table.
-Primary keys must contain unique values.
-A primary key column cannot contain NULL values.
-Each table should have a primary key, and each table can have only ONE primary key.

Posted 24-Jul-12 1:20am

Prasad_Kulkarni

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StianSandberg 24-Jul-12 7:31am

5+The correct answer! Use PK

Prasad_Kulkarni 24-Jul-12 7:42am

Thank you Alluvial!

Solution 3

There is several way you can do this.

- use unique constraints with column Name of your table. it prevents to insert duplicate user-id.

- On submit, you can check whether this user-id is already exist or not in your db table.

- you can provide a button to check uniqueness about user id before submit.

Posted 24-Jul-12 1:24am

ashriv

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Sandeep Mewara · Accepted Answer · 2012-07-24T01:21:00

Solution 2

You need to check it via a query like:

SQL

SELECT COUNT(*) FROM MyTable WHERE UserName  = @CheckUserName

If the count returned from the database is greater than zero then it means that the username is already taken.

Call DB using the query and implement the flow based on the result retrieved. Try!

Posted 24-Jul-12 1:21am

Sandeep Mewara

Comments

_Amy 24-Jul-12 8:00am

Nice Advice. My +5!

Sandeep Mewara 24-Jul-12 8:15am

Thanks.

Based on the vote counts and the 1-votes I got here, it looks like others didnt like my answer much! :)
I am sure they misunderstood the question and everyone had different perspective of the question asked.

_Amy 24-Jul-12 8:25am

Your answer is very clear to me. It's a good idea with no performance issues. We are using this already. :) All the best.

Mohamed Mitwalli 24-Jul-12 10:36am

+5