ColumnAttribute.UpdateCheck

UpdateCheck informs the data context when to verify that a member value in the database has not changed since it was retrieved. The following is the list of valid UpdateCheck values:

Always

Never

WhenChanged

When performing an update without the existence of a dedicated version member, LINQ to SQL generates an UPDATE statement with a WHERE clause that includes the original column values. If the values do not match those in the database, no update occurs, and a conflict is detected, raising an exception.

The default value of UpdateCheck is UpdateCheck.Always. If set to UpdateCheck.Always, conflict detection occurs even if the entity’s member value has not changed.

If the UpdateCheck attribute property is set to UpdateCheck.Never, the member does not participate in conflict detection. You can use this value to effectively switch off conflict detection for a particular member.

If the UpdateCheck attribute property is set to UpdateCheck.WhenChanged, conflict detection for the member occurs only if the value has changed in the entity object.