MUST gives you full control over whether triggers get automatically created, triggers are created in three situations.

Audit Field Triggers

If you have decided to create audit fields on your tables, then triggers are automatically created to update the audit fields when a record is edited.

Unique Index Ignore Null Triggers

Access allows you to create a unique index which ignores null values. In SQL Server NULL is always treated as a unique value, so these indexes can not be created. The equivalent method in SQL Server is to create a Trigger which does not allow duplicate values, unless the value is NULL. Whether you also create a NON-UNIQUE index on the field is then question of whether this would improve performance.

MUST will automatically substitute any Unique Index which ignores null values with a trigger. You can then manually decide at a later date to add back in a NON-UNIQUE index.

WARNING : In Access databases under certain circumstances, the flag showing an index as ignoring nulls can become corrupted, and MUST has special routines which detect this and correct for the problem.

Allow Zero Length Field Checks

Access table text fields have an attribute called “Allow Zero Length” which in older versions of Access always defaulted to NO. This does not have an equivalent setting in SQL Server, and must be replaced by a Check Rule.

In light of newer versions of Access now defaulting the “Allow Zero Length” to YES, the default in MUST is to NOT generate checks for this. If you wish this can be changed for individual database to create the appropriate checks. We would advise against this because to be consistent going forwards you would have to remember to create equivalent checks when adding new text fields, and for many developers including this setting was accidental.

Optional Table Validation Triggers

By default Table Validation Rules are converted to Checks, MUST also offers an option to convert these to Triggers; this is a feature which may appeal to programmers who wish to extend and re-write existing Table Validation to exploit the power of triggers in SQL Server.