Microsoft KB Archive/101847

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PRB: Host_name Function Returns NULL Value

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Q101847

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The information in this article applies to:


 * Microsoft SQL Server version 4.2x

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SYMPTOMS
After upgrading from version 1.x to 4.2, an application or stored procedure that uses the system function host_name to insert a value into a row generates the following error message (error 515):

Attempt to insert the value NULL into column '%.*s', table '%.*s';

column does not allow nulls. Update fails.

CAUSE
The system function host_name has changed behavior between version 1.x and 4.2. The host_name function is supposed to return the value that was set by the front-end application by calling DBSETLHOST. If this was not set by the application, the return value depends on the version of the SQL Server; version 1.x returns a string of 30 spaces, and version 4.2 returns a NULL value.

RESOLUTION
There are several ways to address this situation. The application could be changed to call DBSETLHOST to provide a value. Secondly, the column that is used to store the host_name could be changed to allow NULLs, or, in the case of a stored procedure, the ISNULL function could be used to provide a value when host_name returns NULL.

Additional query words: DB-Lib DB-Library dblib 4.2 4.2a

Keywords : kbother

Issue type :

Technology : kbSQLServSearch kbAudDeveloper kbSQLServ420OS2