Checking For Duplicate IDs

[gregoryt2002]

I have just created a database and need to set up a rule so that when someone enters a certain ID into the form it checks it against the ID's already in the database and returns a error message if it already exists.

Im afraid im a bit of a novice so if anyone can help it would be very appreciated.

Thanks

[MMcCarthy]

I have just created a database and need to set up a rule so that when someone enters a certain ID into the form it checks it against the ID's already in the database and returns a error message if it already exists.

Im afraid im a bit of a novice so if anyone can help it would be very appreciated.

Thanks

Just open the table in design view. Go to the ID field and set Indexed property to Yes (No Duplicates). This will prevent the same ID being entered twice.

Mary

[gregoryt2002]

The Indexed property to Yes (No Duplicates) is already set but when you enter data into a form it allows you to enter all the data and only lets you know there is a duplicate ID when you try to save the record. Is there an instant way of letting a user know when they have entered a duplicate ID?

Tom

[MMcCarthy]

The Indexed property to Yes (No Duplicates) is already set but when you enter data into a form it allows you to enter all the data and only lets you know there is a duplicate ID when you try to save the record. Is there an instant way of letting a user know when they have entered a duplicate ID?

Tom

In the After Update event of the ID textbox which I'm calling txtID ...

Private Sub txtID_AfterUpdate()
   If nz(DLookup("[ID]", "TableName", "[ID]=" & Me!txtID),0) <> 0 Then
      Msgbox "This ID already exists", vbOKOnly
   End If
End Sub
 

Mary

[gregoryt2002]

Well it worked, or thats what i thought to start with. If I put in a ID it warns me if it is in the table but then if i try to change the ID it continues to warn me that it already exists (even if it doesnt.

Very strange, Any ideas?

[MMcCarthy]

Well it worked, or thats what i thought to start with. If I put in a ID it warns me if it is in the table but then if i try to change the ID it continues to warn me that it already exists (even if it doesnt.

Very strange, Any ideas?

Try this ...

Private Sub txtID_AfterUpdate()
   If nz(DLookup("[ID]", "TableName", "[ID]=" & Me!txtID),0) <> 0 Then
      Msgbox "This ID already exists", vbOKOnly
     Me!ID = Null
   End If
End Sub
 

Mary

[gregoryt2002]

Im still getting the error message saying the ID already exists even if it doesn't. Im not sure if its checking the first number of the ID and if that number exists anywhere then its bringing up the message

e.g.

445959 is being checked against anything that has a 4 at the begining.

Im not really sure, i just dont understand why it isnt working.

[MMcCarthy]

Try this ...

Private Sub txtID_AfterUpdate()
Dim tmpID As Long
 
   tmpID = nz(DLookup("[ID]", "TableName", "[ID]=" & Me!txtID),0)
   If tmpID <> 0 Then
        Msgbox "This ID already exists", vbOKOnly
       Me!txtID = Null
   End If
End Sub
 

IF this doesn't work there is something else going on.

Is your ID field a text field or and number field?


Mary

[gregoryt2002]

Yeay, it worked. Thanks for the help and your patience.

Tom

[gregoryt2002]

Yeay, it worked. Thanks for the help and your patience.

Tom

Sorry to bother you again, but i have a new problem. I need to be able to do the same thing as before but also check for letters as well as numbers becuase some of the ID's that im checking against also contain a mix of both.

Is it done in the same way?

[hariharanmca]

Sorry to bother you again, but i have a new problem. I need to be able to do the same thing as before but also check for letters as well as numbers becuase some of the ID's that im checking against also contain a mix of both.

Is it done in the same way?

why don't we go for a Qry

===================== QRY =======================

select * from TableName where FieldId in ( select distinct FieldId from TableName group by FieldId having Count(FieldId)>1)

[MMcCarthy]

Sorry to bother you again, but i have a new problem. I need to be able to do the same thing as before but also check for letters as well as numbers becuase some of the ID's that im checking against also contain a mix of both.

Is it done in the same way?

Try this ...

   tmpID = nz(DLookup("[ID]", "TableName", "[ID]='" & Me!txtID & "'"),"")
   If tmpID <> "" Then
 

Mary

[gregoryt2002]

When running this code I get run time error 13 - Type Mismatch.

Hmmm maybe its worth me thinking about another way round this problem because im sure that we are running out of possible codes :)

[MMcCarthy]

When running this code I get run time error 13 - Type Mismatch.

Hmmm maybe its worth me thinking about another way round this problem because im sure that we are running out of possible codes :)

ID and txtID are both text formats and not numbers, yes?

[gregoryt2002]

ID and txtID are both text formats and not numbers, yes?

Yes they are. Thats the reason I cant really understand why its not working.

Tom