State version pattern

State version pattern provide the version number for every domain object and rows of underlying tables.

There are two main objectives of this pattern:

• Avoid rewriting persistent data when two or more processes modify the same object. NHibernate domain layer will throw an exception if the version of saved object is not the same that current persistent value.
• Modifications counter with possibility to extend this pattern with save all history of data changes, see Tracking-changes-pattern

By default, an attribute Version of integer type will be added to every domain object/table. You can change the name and type if needed.

Configuration example

<Pattern name="StateVersion">
  <Param name="Attribute.Name" value="ObjectVersion" />
  <Param name="Attribute.Type" value="shortint" />
</Pattern>

Configuration parameters

Parameter name	Required?	Description
Attribute.Name	Optional	Name of attribute used to implement version counter. Default is "Version".
Attribute.Type	Optional	Type of version attribute. Default is "int"

Use case code example

	Currency currency = new Currency();
	currency.Code = "USD";
	currency.Name = "US dollar";
	currency.Save();
	Console.WriteLine("Currency '{0}' version is {1}",
		currency.Code,
		currency.Version);