spring-framework / org.springframework.jdbc.support.incrementer / DerbyMaxValueIncrementer

DerbyMaxValueIncrementer

open class DerbyMaxValueIncrementer : AbstractIdentityColumnMaxValueIncrementer

DataFieldMaxValueIncrementer that increments the maximum value of a given Derby table with the equivalent of an auto-increment column. Note: If you use this class, your Derby key column should NOT be defined as an IDENTITY column, as the sequence table does the job.

The sequence is kept in a table. There should be one sequence table per table that needs an auto-generated key.

Derby requires an additional column to be used for the insert since it is impossible to insert a null into the identity column and have the value generated. This is solved by providing the name of a dummy column that also must be created in the sequence table.

Example:

create table tab (id int not null primary key, text varchar(100)); create table tab_sequence (value int generated always as identity, dummy char(1)); insert into tab_sequence (dummy) values(null);

If "cacheSize" is set, the intermediate values are served without querying the database. If the server or your application is stopped or crashes or a transaction is rolled back, the unused values will never be served. The maximum hole size in numbering is consequently the value of cacheSize. HINT: Since Derby supports the JDBC 3.0 getGeneratedKeys method, it is recommended to use IDENTITY columns directly in the tables and then utilizing a org.springframework.jdbc.support.KeyHolder when calling the with the update(PreparedStatementCreator psc, KeyHolder generatedKeyHolder) method of the org.springframework.jdbc.core.JdbcTemplate.

Thanks to Endre Stolsvik for the suggestion!

Author
Thomas Risberg

Author
Juergen Hoeller

Since
2.5

Constructors

<init>

DerbyMaxValueIncrementer()

Default constructor for bean property style usage.

DerbyMaxValueIncrementer(dataSource: DataSource, incrementerName: String, columnName: String)
DerbyMaxValueIncrementer(dataSource: DataSource, incrementerName: String, columnName: String, dummyName: String)

Convenience constructor.

Functions

getDummyName	`open fun getDummyName(): String` Return the name of the dummy column.
setDummyName	`open fun setDummyName(dummyName: String): Unit` Set the name of the dummy column.

Inherited Functions

isDeleteSpecificValues	`open fun isDeleteSpecificValues(): Boolean` Return whether to delete the entire range below the current maximum key value (`false` - the default), or the specifically generated values (`true`).
setDeleteSpecificValues	`open fun setDeleteSpecificValues(deleteSpecificValues: Boolean): Unit` Specify whether to delete the entire range below the current maximum key value (`false` - the default), or the specifically generated values (`true`). The former mode will use a where range clause whereas the latter will use an in clause starting with the lowest value minus 1, just preserving the maximum value.