TCustomEntityDataSet.FieldExpressions

Lists all field expressions of the dataset.

Unit

Syntax

Remarks

The property is used to access field expressions of the dataset. The field expressions mechanism allows to compose complex expressions using operations with entity attributes, and create corresponding dataset fields based on these expressions. Field expressions by something are similar to calculated fields. The main difference is that the logic of computation of a calculated field needs to be written in the handler of the TDataSet.OnCalcFields event, and a field expression can be defined both at run-time, and at design-time.

To manage field expressions at run-time, AddFieldExpression, DeleteFieldExpression and ClearFieldExpressions methods are used.

See Also

• AddFieldExpression
• DeleteFieldExpression
• ClearFieldExpressions