ID Exist Or Not in DB

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Dear Honors!

Am Veeramanikandan, beginner of .NET Environment.

I would like insert the values into table without Duplicates.

So I want to know how to check whether given ID is Exist or Not in Database in ASP.NET using C#.

Thanks in Advance..

Regards,

Veeramanikandan.D

Posted 1-Jun-10 8:47am

drveera

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Prasanta_Prince 9-Jun-11 7:26am

Incase of ID . Try to use Identity.

7 solutions

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#realJSOP · Answer 1 · 2010-06-01T09:00:00

Solution 1

Heres the query:

string query = string.Format("SELECT id from table where id = {0}", myID);

Posted 1-Jun-10 9:00am

#realJSOP

Comments

Andrew Rissing 1-Jun-10 20:05pm

Just a side comment, if "myID" is a string. Use a SQL parameter, rather than just concatenating the string directly yourself, otherwise you open yourself up for SQL injection.

JV9999 17-Jun-11 9:58am

That's not an answer I would suggest to a beginner for the reasons Andrew mentioned. Also using an Identity column and letting the database decide the ID probably is a better fit.

#realJSOP 17-Jun-11 10:55am

He wanted to know how to find out if the id exists. That's all that query does. If the ID exists, it's returned. Otherwise, it's null. Yes, he should have an identity column, but that wasn't his question. Your 1-vote (if it was you) is invalid.

sainath437 · Answer 2 · 2010-06-01T17:52:00

Solution 2

jst make the id as PRIMARY KEY in the database or you can also make it as UNIQUE KEY

Posted 1-Jun-10 17:52pm

sainath437

Rajesh Lagaria · Answer 3 · 2011-06-17T04:30:00

Solution 6

try this :-

SqlCommand comd = new SqlCommand("SELECT id from table where id =1",connection);
              string strID=  comd.ExecuteScalar().ToString();
if(strID==""){MessageBox.Show("ID not Found !!");}else{MessageBox.Show("ID Already Exits !!");}

Posted 17-Jun-11 4:30am

Rajesh Lagaria

Donsw · Answer 4 · 2010-06-02T16:41:00

Solution 3

Like the others said query for it.

but the best is to add a key,
you should probably not make it a primary key if you ever want to change the data value.

Posted 2-Jun-10 16:41pm

Donsw

AMAN281 · Answer 5 · 2011-06-09T01:02:00

Solution 4

But if i want to show a message that is ....

if primary already exist in database then
{
Key Already Exist
}

plz send me the complete code I m a new in C#.net

Posted 9-Jun-11 1:02am

AMAN281

Comments

Simon_Whale 17-Jun-11 9:52am

I would have a good look at this site

http://msdn.microsoft.com/en-gb/beginner/default.aspx

ori2694 · Answer 6 · 2011-06-17T04:46:00

Solution 7

If I understand correctly, you want to take the highest ID and add it one.
If so, use this query:

SELECT MAX(ID) AS ID FROM table

This give you the highest ID in the table (Of course ID column's type should be a integer).

Posted 17-Jun-11 4:46am

ori2694

mhwasim · Answer 7 · 2011-06-17T03:43:00

Solution 5

Use this code

SQL

string query = string.Format(@"IF EXISTS (SELECT NULL FROM Table WHERE ID = {0})
SELECT 'Key Already Exists'
ELSE
SELECT 'Key Not Found'", myID);

Hope this will help...

Thanks

Posted 17-Jun-11 3:43am

mhwasim