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    TField.CustomConstraint

    Custom constraint for the field's value.

    Declaration

    Source position: db.pas line 474

    published property CustomConstraint: string;

    Description

    CustomConstraint may contain a constraint that will be enforced when the dataset posts it's data. It should be a SQL-like expression that results in a True or False value. Examples of valid constraints are: 

    Salary < 10000
YearsEducation < Age

    If the constraint is not satisfied when the record is posted, then an exception will be raised with the value of ConstraintErrorMessage as a message.

    This feature is not yet implemented in FPC.

    See also

    Name Description
    TField.ConstraintErrorMessage Message to display if the CustomConstraint constraint is violated.
    TField.ImportedConstraint Constraint for the field value on the level of the underlying database.