The purpose of this section is to provide a detailed information about what will be visible in the Mapping Information view, when you select an interface field in the treeview.
The Mapping Information view should look like the snapshot below:
The following options are available:
- Transient (skip this field) - check this if the field should not be stored in the database.
- Serialize to Blob - check this if the field's value should be stored serialized into a Blob column.
- Field behavior - defines the field behavior. It can be readwrite, readonly or insertonly. The default is readwrite.
- Columns - the Columns drop-down list contains the list of columns that are created for the field. Reference fields of Interface type are mapped to two or more columns. One column identifies the type of the referenced instance (shipping_address_class) and the other column/s hold(s) its primary key/s (shipping_address_id). The name of the type of the referenced instance is based on the DBColumn Name specified. Check out the snapshot below, it shows the possible values in the Columns combobox for the current example.
- Name - contains the name of the selected column in the Columns combo box. OpenAccess gives you the ability to edit each column name at your discretion.
- Type - contains a drop-down list with the supported database datatypes.
- SQL Type - contains a list with the supported SQL types for the selected database.
- Length - sets the length (or precision) of the database column.
- Scale - sets the scale (digits after the decimal point).
- Converter - currently the data converter feature is not implemented.
- Part of primary key - signals whether the field is part of the primary key or not. This is specified by the identity class in case of multiple field identity and by the field that holds the identity information, in case of single field identity. In case of the internal identity, none of the users fields will serve as primary key, so this box is never checked while using internal identity. This option is read-only.
- Throw an exception on commit if field is null - controls the treatment of null values. By default the field is mapped to a column that allows null values. If "throw an exception" is checked then the field is mapped to a column that does not allow null values. In such a case, an exception on commit time will be thrown, if the value of the field is null.
- Cascading delete - in case of cascading deletes, if a "Delete" occurs, the referenced object(s) will also be deleted (including their dependant referenced objects ...). The [OpenAccess.Depend] attribute is added to the referenced persistent class or to the persistent values in a collection or array.
- Default fetch group - controls whether the field will be included in the default fetchgroup or not.
- Implemented class grid - the grid lists the valid class/classes that implement the interface. In the case of the above image, the reference field owner can point to Address.