How to use delete query for sql database in c#?

Question

I want to delete a row corresponding to a particular IP address .. I have written this query :

  string dlt = @"DELETE [LocationIP], [LocationName],[LocationID],
                [NoOfUsers],[MinutesUsed] FROM [LocationInfo] WHERE LocationIP=@ipadd";
  SqlCommand cmd = new SqlCommand(dlt, sqlcon_QOEMetrices);
  cmd.Parameters.Add("@ipadd", SqlDbType.NChar, 15);

  cmd.Parameters["@ipadd"].Value = ipadd;

where ip address is stored in the string variable ipadd This query is not showing any result but even not giving any error...

Oded · Accepted Answer · 2012-04-04 10:16:04Z

3

You need to execute your command.

Something like:

cmd.ExecuteNonQuery();

answered Apr 4, 2012 at 10:16

Oded

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3 Comments

Oded Over a year ago

@johntotetwoo - Thanks for the correction. You could have edited that yourself, you know :)

Oded Over a year ago

@AdamHouldsworth - as did I... but within the grace period, so we will never know who got it first...

Adam Houldsworth Over a year ago

@Oded lol guessing you did otherwise my name would be up there under the edit history I think.

Mithrandir · Accepted Answer · 2012-04-04 10:17:41Z

0

Where is the execution of your query?

 cmd.ExecuteNonQuery();

answered Apr 4, 2012 at 10:17

Mithrandir

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Comments

Jodrell · Accepted Answer · 2012-04-04 10:22:24Z

0

Your SQL is wrong, you don't want a select list in a DELETE statement.

string dlt = @"DELETE FROM [LocationInfo] WHERE LocationIP=@ipadd";
SqlCommand cmd = new SqlCommand(dlt, sqlcon_QOEMetrices);
cmd.Parameters.Add("@ipadd", SqlDbType.NChar, 15);

would suffice. I then assume you are doing somthing like

cmd.ExecuteNonQuery()

answered Apr 4, 2012 at 10:22

Jodrell

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Comments

las · Accepted Answer · 2012-04-04 10:25:35Z

-2

Try this simple query and execute,

 "DELETE FROM LocationInfo WHERE LocationIP=@ipadd"

  SqlCommand cmd = new SqlCommand(dlt, sqlcon_QOEMetrices);
  cmd.Parameters.Add("@ipadd", SqlDbType.NChar, 15);

  cmd.Parameters["@ipadd"].Value = ipadd;
cmd.ExecuteNonQuery();

edited Apr 4, 2012 at 10:25

answered Apr 4, 2012 at 10:18

las

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3 Comments

Oded Over a year ago

You need to learn about SQL Injection. Concatenating SQL is not a good idea from a security point of view.

Oded Over a year ago

The code the OP posted is actually much better in this regard.

Oded Over a year ago

Then perhaps you should delete this answer, as it is showing a bad practice?

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