>>The SQL is :
>>
>>
>SELECT prototype.*, trknum.*
>>FROM trknum INNER JOIN prototype ON trknum.trknum = prototype.trknum;
>>
>>TRKNUM only has 1 field: TRKNUM and it is the primary key
>>PROTOTYPE has a bunch of fields with ID being the primary key
>
>I think that the update query cannot find the unique field to be updated due to the lack of a where clause. What trknum is going to be updated? The way the update statement is written all trknums would be changed to the value in mtxt0.
>Also is prototype the name of the query or are you trying to refer to the base table?
>
>
>Actually I wanted to write 2 insert statements:
>
>

DoCmd.RunSQL ("update prototype set trknum = " & mtxt0 &  ";")
>-----this will update ALL trknum to mtxt0 -------
>and
>DoCmd.RunSQL ("update prototype set cycle = " & mtxt1 &  " where prototype = '" & mtxt36 & "';")
>------this will only update 1 record ------

>
>Prototype is the name of a table not a query.

This looks good. If you're referring to the table directly then there is no reason why the field would not be updatable, unless prototype is a linked table that has been marked as non-updatable. Check the updatable property of the tabledef, and also see if the field hasn't been marked as read-only.

How is the cycle field defined in the table? What is the exatc error number and description?