[Overview][Constants][Types][Classes][Procedures and functions][Variables][Index] | Reference for unit 'DB' (#fcl)

# TField.Required

Does the field require a value

## Declaration

Source position: db.pas line 462

`published property TField.Required : Boolean read FRequired write FRequired;`

## Description

Required determines whether the field needs a value when posting the data: when a dataset posts the changed made to a record (new or existing), it will check whether all fields with the Required property have a value assigned to them. If not, an exception will be raised. Descendents of TDataset will set the property to True when opening the dataset, depending on whether the field is required in the underlying data engine. For fields that are not required by the database engine, the programmer can still set the property to True if the business logic requires a field.

## See also

TDataset.Open |  | Activate the dataset: Fetch data into memory.
ReadOnly |  | Is the field read-only
Visible |  | Should the field be shown in grids