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TableDef.CreateField Method (DAO)

Creates a new Field object (Microsoft Access workspaces only).

expression .CreateField(Name, Type, Size)

expression A variable that represents a TableDef object.

Parameters

Name

Required/Optional

Data Type

Description

Name

Optional

Variant

A String that uniquely names the new Field object. See the Name property for details on valid Field names.

Type

Optional

Variant

A constant that determines the data type of the new Field object. See the Type property for valid data types.

Size

Optional

Variant

An Integer that indicates the maximum size, in bytes, of a Field object that contains text. See the Size property for valid size values. This argument is ignored for numeric and fixed-width fields.

Return Value

Field

You can use the CreateField method to create a new field, as well as specify the name, data type, and size of the field. If you omit one or more of the optional parts when you use CreateField, you can use an appropriate assignment statement to set or reset the corresponding property before you append the new object to a collection. After you append the new object, you can alter some but not all of its property settings. See the individual property topics for more details.

The type and Size arguments apply only to Field objects in a TableDef object. These arguments are ignored when a Field object is associated with an Index or Relation object.

If Name refers to an object that is already a member of the collection, a run-time error occurs when you use the Append method.

To remove a Field object from a Fields collection, use the Delete method on the collection. You can't delete a Field object from a TableDef object's Fields collection after you create an index that references the field.

Link provided by: Community Member Icon The UtterAccess community | About the Contributors

The following example shows how to create a calculated field. The CreateField method creates a field named FullName. The Expression property is then set to the expression that calculates the value of the field.

Sample code provided by: Access 2010 Programmers Reference book cover The Microsoft Access 2010 Programmer’s Reference | About the Contributors

Sub CreateCalculatedField()
    Dim dbs As DAO.Database
    Dim tdf As DAO.TableDef
    Dim fld As DAO.Field2
    
    ' get the database
    Set dbs = CurrentDb()
    
    ' create the table
    Set tdf = dbs.CreateTableDef("tblContactsCalcField")
    
    ' create the fields: first name, last name
    tdf.Fields.Append tdf.CreateField("FirstName", dbText, 20)
    tdf.Fields.Append tdf.CreateField("LastName", dbText, 20)
    
    ' create the calculated field: full name
    Set fld = tdf.CreateField("FullName", dbText, 50)
    fld.Expression = "[FirstName] & "" "" & [LastName]"
    tdf.Fields.Append fld
    
    ' append the table and cleanup
    dbs.TableDefs.Append tdf
    
Cleanup:
    Set fld = Nothing
    Set tdf = Nothing
    Set dbs = Nothing
End Sub

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