SET TRUENULLCREATE

SET TRUENULLCREATE

The SET TRUENULLCREATE statement turns on or off true NULLs when you create new tables.

SET TRUENULLCREATE = < on | off >

Pervasive PSQL v11 SP3 allows you to set the default format for creation of tables with regard to NULL support. Normally, the product creates new tables using the true NULL data record format, which adds a NULL indicator byte to the beginning of every field. By turning off this engine setting using an SQL statement, you can create new tables that use the legacy NULL data record format that was used in Pervasive.SQL 7.

The creation mode remains in effect until it is changed by issuing the statement again, or until the connection is disconnected. Because this setting is maintained on a per-connection basis, separate database connections can maintain different creation modes, even within the same application. Every connection starts with the setting in default mode, where new tables are created with true NULL support.

This feature does not affect existing tables or available column data types. All tables are created using Pervasive PSQL data types. For example, old data types such as NOTE or LVAR are not available for use regardless of which type of NULL support is selected.

Also see the discussion about nullable data types under INSERT.

This setting can be toggled only by using SQL. It cannot be set using the Pervasive PSQL Control Center.

To toggle the setting and specify that new tables should be created with legacy NULL support, use this SQL statement:

SET TRUENULLCREATE=OFF

To toggle the setting and return the engine to the default, which is table creation with true NULL support, use this SQL statement:

SET TRUENULLCREATE=ON