OpenEdge Data Management: DataServer for Microsoft SQL Server

Modifying the run-time schema check
Modifying the run-time schema check
At runtime, the DataServer for MS SQL Server performs a schema check to match a
table definition in the data source against the schema image in the schema holder. It
performs this task once for each table utilized in a OpenEdge procedure. In order to
retrieve table attributes without having to access data, the DataServer executes the
following SQL statement against the data source:
SELECT * FROM table-name WHERE 1 = 2.
Skip schema verification
When r-code runs (each time a table, view, or buffer is opened), the DataServer checks
the data definitions of the MS SQL Server data source to ensure the data definitions
match the schema definitions in the schema holder. If the definitions do not match, the
DataServer returns an error.
Unmatched definitions can cause corruption of data. For this reason, checking the
integrity of data definitions at run time ensures the data corruption due to unmatched
definitions will not occur. The skip schema check feature can be used to bypass this
check at run time. Because definition verification is time consuming in a production
environment, you might consider using the -Dsrv skip_schema_check startup
parameter if your environment allows. You might consider using this option to increase
performance, but only if you are certain that the data definitions in the data source
match your schema holder definitions.
Note: The dataserv.lg log file denotes when the DataServer skips the schema
check.
The following example shows how to use the -Dsrv parameter with the skip schema
check option in the CONNECT statement:
CONNECT data-source-name -ld logical-name -dt MSS
-Dsrv skip_schema_check
Caution: If you use the skip schema check option, the DataServer skips the schema
check and does not detect discrepancies between the schema definitions
and the data definitions. If there are discrepancies and the DataServer
continues to process queries, inserts, and deletions, your data can become
corrupted. Progress Software Corporation recommends that you weigh
carefully the performance benefit against the risk to your database before
deciding to use -Dsrv skip_schema_check.
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