Why does INSERT statement delete previous records?

[the_grove_man]

I am writing an application that populates a database from text files.
I have an insert command which works fine, however, it overwrites
anything that was in the database before.

Looking for a little help: (the database starts off empty)

Here is my code:

Dim x As Integer = rtf4.Find("<sdr_string>")
Dim y As Integer = rtf4.Find("</sdr_string>")

Try

rtf4.Select(x + 4, ((y - 1) - (x + 4)) + 10)
rtf4.ScrollToCaret()
rtf4.Focus()
rtf4.Cut()
Dim j As String = Clipboard.GetText.Trim.ToString
Dim t As String = j.Substring(8, j.Length - 17).Trim

Dim command As String
command = "INSERT into ParentChild(signal, FileName, Sheet)
values('" & t & "','" & My.Forms.Form1.Title.Replace(".edit", "") &
"','" & My.Forms.Form1.Title.Substring(My.Forms.Form1.Title.Length - 8,
3) & "'" & ")"

If cn.State = ConnectionState.Closed Then
cn.Open()
End If

Dim cmd As New OleDb.OleDbCommand(command, cn)
cmd.CommandType = CommandType.Text
cmd.ExecuteNonQuery()
cn.Close()
Button2.PerformClick()

Catch ex As Exception
If MessageBox.Show("Database has been prepped", "Database
Entries", MessageBoxButtons.OK, MessageBoxIcon.Information) =
Windows.Forms.DialogResult.OK Then
Me.Close()
End If
Exit Sub
End Try

 

[W.G. Ryan - MVP]

What do you mean it overwrites stuff, as in an Update when it should be an
insert? Also, the sql statment you're using is dangerous, paramaterize it
or be prepared to deal with all the h3ll associated with not paramaterizing.
I'd also recommend moving the cn.Close() down to a finally block, otherwise
it may never be excecuted. Lemme know the answer to the first and hopefully
we can help nail it down.

 

[Val Mazur \(MVP\)]

Hi,

INSERT SQL statement cannot overwrite data in a database. It always insert
new record. Only UPDATE could do this. How do you check that it overwrites
the data? Also, as William pointed, your SQL statements could be pretty
dangerous due to the fact that you are constructing them using
concatenation. It could lead to the SQL injection.

 

[the_grove_man]

hi guys, thank you all for your input.
I know that it is overwriting other records because after it dumps the
data in the database (Which it does correctly), it overwrites previous
information in the the table.

For example, let say I run one .edit file through my app called
316720_01.edit.
My app parses the file and dumps data in three columns.

When I view the data, all is fine. Then when I run my next .edit file,
the first one gets overwritten.
Can you guys provide an example how else I can do this to avoid this or
clear up my "dangerous" SQL statement.

Thanks,
John

 

[Val Mazur \(MVP\)]

It could be because you are using Cut method that basically copies data into
the clipboard, but deletes data from the source.