true, to allow executing SQL queries on the server side; otherwise, false.
Executing custom SQL queries is forbidden by default. If you allow executing custom SQL queries, you can use the EnableCustomSql property to enable a user to specify a custom SQL string in the Data Source wizard.
The use of custom SQL queries can lead to inadvertent or unauthorized modifications to your data/database structure. Therefore, make sure that you follow best practices and implement the appropriate end-user read/write privileges at the database level.