Updating custom tab

I'm having a problem with my new custom tab. I've created a table with the column id_key int that is primary and customer_no. When I try to update a record in the custom tab in Tess it appears to be passing the customer_no as the id_key, and the update fails. 

So my table was created like this:

 

CREATE TABLE [dbo].[lt_student](

[id_key] [int] NOT NULL,

[customer_no] [int] NULL,

(other columns)...
PRIMARY KEY CLUSTERED 
(
[id_key] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]
but when I update a record in Tess I get this message:
Row changed between retrieve and update.
No changes made to database.
UPDATE lt_student SET notes = 'i love notes......' WHERE id_key = 705595 
That number is the customer_no not the id_key for that record. Did I do something wrong in the setup?

 



[edited by: Brian Graham at 3:18 PM (GMT -6) on 3 Feb 2012]