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SetIfNull

procedure SetIfNull(aNewValue: Variant)

Example​

procedure ScriptEvent(var Value: variant);
begin
  Field.SetIfNull('UNKNOWN');
  Value := Field.Value;
end;

Usage​

SetIfNull assigns a replacement only when the field Variant is Null, Empty or Clear.

Additional Technical Info​

SetIfNull reads the current field once as a Variant. It assigns aNewValue only when that Variant satisfies VarIsNull, VarIsEmpty or VarIsClear.

Empty string, whitespace text, numeric zero, Boolean false and date/time zero are values and do not qualify. This makes the method narrower than SetIfEmpty and SetIfZero.

The replacement is written through TField.Value. Concrete-field conversion, range/read-only/edit-state checks and validation can raise. A successful write changes only the active record buffer; the method does not Post, ApplyUpdates or commit. If the current value does not qualify, the method is a no-op.

Although Empty and Clear are unusual field values, the implementation deliberately accepts all three Variant states. The field reference remains owned by the active dataset and follows its cursor.

External references

Created 2026-07-15