Required Property

Applies To

Field Object, Index Object.

Description

Sets or returns a value that indicates whether a Field object requires a non-Null value or whether all the fields in an Index object must be filled in. For an object not yet appended to a collection, this property is read/write. For an Index object, this property setting is read-only for objects appended to Indexes collections in Recordset and TableDef objects.

Settings and Return Values

The setting or return value is a Boolean expression indicating whether an object requires a non-Null value. True indicates that a Null value is not allowed.

Remarks

For a Field object, use of the Required property depends on its parent object, as shown in the following table.

Parent Object	Usage

Index	Not supported
QueryDef	Read-only
Recordset	Read-only
Relation	Not supported
TableDef	Read/write

For a Field object, you can use the Required property along with the AllowZeroLength, ValidateOnSet, or ValidationRule property to determine the validity of the Value property setting for that Field object. If the Required property is set to False (0), the field can contain Null values as well as values that meet the conditions specified by the AllowZeroLength and ValidationRule property settings.

Tip

When you can set this property for either an Index object or a Field object, set it for the Field object. The validity of the property setting for a Field object is checked before that of an Index object.

See Also

AllowZeroLength Property, QueryDef Object, Required Property, ValidateOnSet Property, ValidationRule Property, ValidationText Property, Value Property.

Example (Microsoft Access)

The following example creates a new Index object on an Employees table and sets the Required property for the index. The new index consists of two fields, LastName and FirstName.

Sub NewIndex()
    Dim dbs As Database, tdf As TableDef, idx As Index
    Dim fldLastName As Field, fldFirstName As Field, rst As Recordset

    ' Return Database variable that points to current database.
    Set dbs = CurrentDb
    Set tdf = dbs.TableDefs!Employees
    ' Return Index object that points to new index.
    Set idx = tdf.CreateIndex("FullName")
    ' Create and append index fields.
    Set fldLastName = idx.CreateField("LastName", dbText)
    Set fldFirstName = idx.CreateField("FirstName", dbText)
    idx.Fields.Append fldLastName
    idx.Fields.Append fldFirstName
    ' Ensure value is entered for each field in the index.
    idx.Required = True
    ' Append Index object.
    tdf.Indexes.Append idx
End Sub