Hibernate generator element

Hibernate generator element generates the primary key for new record. There are provided options provided by the generator method to be used in different situations.

 

The <generator> element

 

Here is the example

<Generator class = "assigned"/>

Here are the list of some commonly used generators in hibernate:

 

Generator	Description
Increment	It generates identifiers of type long, short or int that are unique only when no other process is inserting data into the same table. It shocould not the used in the clustered environment.
Identity	It supports identity columns in DB2, MySQL, ms SQL Server, Sybase and hypersonicsql. The returned identifier is of type long, short or Int.
Sequence	The sequence generator uses a sequence in DB2, PostgreSQL, Oracle, sap db, mckoi or a generator in InterBase. The returned identifier is of type long, short or int
HiLo	The HiLo generator uses a hi/LO algorithm to efficiently generate identifiers of type long, short or Int, given a table and column (by default hibernate_unique_key and next_hi respectively) as a source of HI values. the HI/LO algorithm generates identifiers that are unique only for a particle database. do not use this generator with connections enlisted with JTA or with a user-supplied connection.
Seqhilo	The seqhilo generator uses a hi/LO algorithm to efficiently generate identifiers of type long, short or Int, given a named database sequence.
UUID	The UUID generate uses a 128-bit UUID algorithm to generate identifiers of Type string, unique within a network (the IP address is used ). the UUID is encoded as a string of hexadecimal digits of Length 32.
Guid	It uses a database-generated guid string on ms SQL Server and MySQL.
Native	It picks identity, sequence or HiLo depending upon the capabilities of the underlying database.
Assigned	Lets the application to assign an identifier to the object before save () is called. This is the default strategy if no <generator> element is specified.
Select	Retrieves a primary key assigned by a database trigger by selecting the row by some unique key and retrieving the primary key value.
Foreign	Uses the identifier of another associated object. usually used in conjunction with a <one-to-one> Primary Key Association.