Top Description Fields Constructors Methods
org.springframework.jdbc.support.incrementer

public Class DerbyMaxValueIncrementer

extends AbstractIdentityColumnMaxValueIncrementer
Class Inheritance
Imports
javax.sql.DataSource
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 getGeneratedKeys method, it is recommended to use IDENTITY columns directly in the tables and then utilize a org.springframework.jdbc.support.KeyHolder when calling the update(PreparedStatementCreator psc, KeyHolder generatedKeyHolder) method of the org.springframework.jdbc.core.JdbcTemplate.

Thanks to Endre Stolsvik for the suggestion!

Authors
Thomas Risberg, Juergen Hoeller
Since
2.5

Field Summary

Modifier and TypeField and Description
private static final String
DEFAULT_DUMMY_NAME

The default for dummy name.

private String
dummyName

The name of the dummy column used for inserts.

Constructor Summary

AccessConstructor and Description
public
DerbyMaxValueIncrementer()

Default constructor for bean property style usage.

public
DerbyMaxValueIncrementer(DataSource
the DataSource to use
dataSource, String
the name of the sequence/table to use
incrementerName, String
the name of the column in the sequence table to use
columnName)

Convenience constructor.

public
DerbyMaxValueIncrementer(DataSource
the DataSource to use
dataSource, String
the name of the sequence/table to use
incrementerName, String
the name of the column in the sequence table to use
columnName, String
the name of the dummy column used for inserts
dummyName)

Convenience constructor.

Method Summary

Modifier and TypeMethod and Description
public String
getDummyName()

Return the name of the dummy column.

protected String
getIdentityStatement()

Implements abstract org.springframework.jdbc.support.incrementer.AbstractIdentityColumnMaxValueIncrementer.getIdentityStatement.

Statement to use to obtain the current identity value.
protected String
getIncrementStatement()

Implements abstract org.springframework.jdbc.support.incrementer.AbstractIdentityColumnMaxValueIncrementer.getIncrementStatement.

Statement to use to increment the "sequence" value.
public void
setDummyName(String dummyName)

Set the name of the dummy column.

Inherited from org.springframework.jdbc.support.incrementer.AbstractIdentityColumnMaxValueIncrementer:
getDeleteStatementgetNextKeyisDeleteSpecificValuessetDeleteSpecificValues

Field Detail

DEFAULT_DUMMY_NAMEback to summary
private static final String DEFAULT_DUMMY_NAME

The default for dummy name.

dummyNameback to summary
private String dummyName

The name of the dummy column used for inserts.

Constructor Detail

DerbyMaxValueIncrementerback to summary
public DerbyMaxValueIncrementer()

Default constructor for bean property style usage.

See Also
setDataSource, setIncrementerName, setColumnName
DerbyMaxValueIncrementerback to summary
public DerbyMaxValueIncrementer(DataSource dataSource, String incrementerName, String columnName)

Convenience constructor.

Parameters
dataSource:DataSource

the DataSource to use

incrementerName:String

the name of the sequence/table to use

columnName:String

the name of the column in the sequence table to use

DerbyMaxValueIncrementerback to summary
public DerbyMaxValueIncrementer(DataSource dataSource, String incrementerName, String columnName, String dummyName)

Convenience constructor.

Parameters
dataSource:DataSource

the DataSource to use

incrementerName:String

the name of the sequence/table to use

columnName:String

the name of the column in the sequence table to use

dummyName:String

the name of the dummy column used for inserts

Method Detail

getDummyNameback to summary
public String getDummyName()

Return the name of the dummy column.

getIdentityStatementback to summary
protected String getIdentityStatement()

Implements abstract org.springframework.jdbc.support.incrementer.AbstractIdentityColumnMaxValueIncrementer.getIdentityStatement.

Doc from org.springframework.jdbc.support.incrementer.AbstractIdentityColumnMaxValueIncrementer.getIdentityStatement.

Statement to use to obtain the current identity value.

Returns:String

the SQL statement to use

Annotations
@Override
getIncrementStatementback to summary
protected String getIncrementStatement()

Implements abstract org.springframework.jdbc.support.incrementer.AbstractIdentityColumnMaxValueIncrementer.getIncrementStatement.

Doc from org.springframework.jdbc.support.incrementer.AbstractIdentityColumnMaxValueIncrementer.getIncrementStatement.

Statement to use to increment the "sequence" value.

Returns:String

the SQL statement to use

Annotations
@Override
setDummyNameback to summary
public void setDummyName(String dummyName)

Set the name of the dummy column.