evaluating expressions stored in table

Hi,

I need to evaluate an expression that I have stored in a table, and not sure how to force evaluation of a column value.

Some background. This is a generic testing application that we're using to test source to target ETL's.
The specifics of the test expression depend on the actual tables involved. Typicallly it's been table_a.col_a = table_b.col_b but now they want to use inequality or other operators.
The tester's define the test criteria in a table, then we use that criteria to actually score the runtime results.

In my design I have 3 tables.
Test - stores the test definition
Testrun - stores the actual sql for a specific execution of a test
Testscore - stores the actual values of the source and target values. The scores are stored in different rows, with a common name to allow them to be matched in the query.

The pass/fail query looks something like this

Update testscore
Set metricstatus = case when table_a.col_a = table_b.col_b then 'PASS' else 'FAIL' end
..
Where testrunid=x

I want to replace the table_a.col_a = table_b.col_b with the expression stored in the test table and evaluate.

I'm thinking - it's dynamic sql, so I need to build the statement and then evaluate using a function.

Anybody have any comments?

Thanks

Doug Little

Sr. Data Warehouse Architect | Business Intelligence Architecture | Orbitz Worldwide
500 W. Madison, Suite 1000 Chicago IL 60661| Office 312.260.2588 | Fax 312.894.5164 | Cell 847-997-5741
Douglas(dot)Little(at)orbitz(dot)com<mailto:Douglas(dot)Little(at)orbitz(dot)com>
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