FIX: UPDATE of Table Column with a FOREIGN KEY Constraint May Fail with Msg 8623 (214818)

SYMPTOMS

Attempting to update a column using a declared variable may fail if that column has a FOREIGN KEY (FK) constraint and the FROM clause references multiple tables. In such cases, the following error message occurs:

Server: Msg 8623, Level 16, State 2, Line 8
Internal Query Processor Error: The query processor could not produce a query plan.

For example, the following would cause the error:

declare @c1 int
select @c1 =
   update secondary_tbl set c1 = @c1
   from secondary_tbl p,child_1 t1, child_2 t2
   where  p.s1 = t1.s1

WORKAROUND

To work around this problem, use CONVERT to cast the variable to its data type. In the preceding example, replace:

update secondary_tbl set c1 = @c1

with:

update secondary_tbl set c1 = convert(int,@c1)

STATUS

Microsoft has confirmed this to be a problem in SQL Server 7.0. This problem has been corrected in U.S. Service Pack 2 for Microsoft SQL Server 7.0. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

254561 INF: How to Obtain Service Pack 2 for Microsoft SQL Server 7.0 and Microsoft Data Engine (MSDE) 1.0

For more information, contact your primary support provider.