delete query not working

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how to delete the gridview data when submit button click

I have gridview and a button on my webpage.

when pageloads, the data displays on gridview.

so when i clicks the submit button i want to delete the complete data from table.
so it cannot be displayed in gridview.

this is my code

SqlConnection conDelete = new SqlConnection(_connString);
         SqlCommand cmdDelete = new SqlCommand();
         cmdDelete.Connection = conDelete;
        cmdDelete.CommandText = "Delete from students";
        using (cmdDelete)
        {
            conDelete.Open();

            cmdDelete.ExecuteNonQuery();
            conDelete.Close();
        }

this is not working please help.

thanks

Posted 15-Apr-13 2:21am

Ubaid ur Rahman IT

Updated 15-Apr-13 2:25am

Bojjaiah

v2

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Bojjaiah 15-Apr-13 8:25am

First you have to know the delete query and try to execute in sqlserver after that you can try c#. your delete query is wrong DELETE FROM TABLENAME WHERE condition<search>

fjdiewornncalwe 15-Apr-13 9:34am

It isn't wrong syntax. This syntax is perfectly valid, but dangerous.

Naz_Firdouse 15-Apr-13 8:55am

no need of where condition for delete query...
check this
http://msdn.microsoft.com/en-us/library/ms189245(v=sql.105).aspx

rmksiva 15-Apr-13 9:04am

it shows any Error ? then please share

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Maciej Los · Answer 1 · 2013-04-15T02:34:00

You need to define connection for sqlcommand[^], like this:

C#

SqlConnection conDelete = new SqlConnection(_connString);
conDelete.Open();
SqlCommand cmdDelete = new SqlCommand("DELETE FROM Students WHERE StudentId=1", conDelete);
int retVal = cmdDelete.ExecuteNonQuery();
//retval stores value for recoreds affected

Remember, you need to define records range to DELETE (T-SQL)[^], but if you want to delete all data, WHERE statement is not needed:

SQL

DELETE 
FROM Students

Above query differs from TRUNCATE TABLE (T-SQL)[^].

Raje_ · Answer 2 · 2013-04-15T02:33:00

Solution 1

Use this :-

SQL

TRUNCATE TABLE students

Good luck

Posted 15-Apr-13 2:33am

Raje_

Updated 15-Apr-13 2:34am

v2

TrushnaK · Answer 3 · 2013-04-15T03:04:00

try for this:-

VB

Dim con As New SqlConnection
Dim cmd As New SqlCommand
Try
con.ConnectionString = "Data Source=atisource;Initial Catalog=BillingSys;Persist Security Info=True;User ID=sa;Password=12345678"
con.Open()
cmd.Connection = con
cmd.CommandText = "DELETE FROM table_name"
cmd.ExecuteNonQuery()

Catch ex As Exception
MessageBox.Show("Error while deleting record on table..." & ex.Message, "Delete Records")
Finally
con.Close()
End Try

sainadh.chintha · Answer 4 · 2013-04-15T02:42:00

Solution 3

try this !!

where condition is needed for delete query..

string query = "delete from tab1 where id=" + ddl.SelectedValue;
        SqlCommand cmd = new SqlCommand();
        cmd.Connection = con;
        cmd.CommandText = query;
        con.Open();
        cmd.ExecuteNonQuery();
        con.Close();

Posted 15-Apr-13 2:42am

sainadh.chintha

Comments

Naz_Firdouse 15-Apr-13 8:55am

no need of where condition for delete query...
check this
http://msdn.microsoft.com/en-us/library/ms189245(v=sql.105).aspx

sainadh.chintha 15-Apr-13 9:13am

otherwise simply use, "delete from tab1". It is working for me..

delete query not working

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