From Xojo Documentation

Property (As Boolean )
aREALSQLdatabase.MultiUser = newBooleanValue
BooleanValue = aREALSQLdatabase.MultiUser

New in 2011r1

Supported for all project types and targets.

Enables the SQLite Write-Ahead Logging (WAL) mode which can improve performance of database writes. This is especially useful when multiple users are writing to the database, as can be the case with web applications.