Attribute mappings

Chapter 11 Generating .NET 2.0 Persistent Objects and Windows Applications

Attribute mappings

Attributes can be migrated attributes or ordinary attributes. Ordinary attributes can be mapped to columns or formulas. Migrated attributes do not require attribute mapping.

The following types of mapping are possible:

Map attribute to formula - When mapping an attribute to a formula, you should ensure that the syntax is correct. There is no column in the source table of the attribute mapping.
Component attribute mapping - A component class can define the attribute mapping as for other classes, except that there is no primary identifier.
Discriminator mapping - In inheritance mapping with a one-table-per-hierarchy strategy, the discriminator needs to be specified in the root class. You can define the discriminator in the NHibernate tab of the class property sheet.

NHibernate-specific attribute mapping options are defined in the NHibernate tab of the Attribute property sheet.

Option	Description
Generate finder function	Generates a finder function for the attribute.
NHibernate type	Specifies a name that indicates the NHibernate type.
Property access	Specifies the strategy that NHibernate should use for accessing the property value.
Id unsaved value	Specifies the value of an unsaved id.
Insert	Specifies that the mapped columns should be included in any SQL INSERT statements.
Update	Specifies that the mapped columns should be included in any SQL UPDATE statements.
Optimistic lock	Specifies that updates to this property require acquisition of the optimistic lock.
Lazy	Specifies that this property should be fetched lazily when the instance variable is first accessed (requires build-time byte code instrumentation).