Package io.hypersistence.utils.hibernate.id

Class BatchSequenceGenerator

java.lang.Object

io.hypersistence.utils.hibernate.id.BatchSequenceGenerator

All Implemented Interfaces:

Serializable, org.hibernate.boot.model.relational.ExportableProducer, org.hibernate.generator.BeforeExecutionGenerator, org.hibernate.generator.Generator, org.hibernate.id.BulkInsertionCapableIdentifierGenerator, org.hibernate.id.Configurable, org.hibernate.id.factory.spi.StandardGenerator, org.hibernate.id.IdentifierGenerator, org.hibernate.id.OptimizableGenerator, org.hibernate.id.PersistentIdentifierGenerator

public class BatchSequenceGenerator
extends Object
implements org.hibernate.id.BulkInsertionCapableIdentifierGenerator, org.hibernate.id.PersistentIdentifierGenerator, org.hibernate.id.Configurable

A sequence generator that uses a recursive query to fetch multiple values from a sequence in a single database access.

Configuration

 @Id
 @BatchSequence(name = "SOME_SEQUENCE_NAME", fetch_size = SOME_FETCH_SIZE_VALUE)
 private Long someColumnName;
 

SQL

Per default the generated SELECT will look something like this

 WITH RECURSIVE t(n) AS (
   SELECT 1
     UNION ALL
   SELECT n + 1
   FROM t
   WHERE n < ?)
 SELECT nextval(seq_xxx)
   FROM t;
 

DB2

For DB2 the generated SELECT will look something like this

 WITH t(n) AS (
   SELECT 1 AS n
     FROM (VALUES 1)
       UNION ALL
     SELECT n + 1 AS n
       FROM t
      WHERE n < ?)
 SELECT next value for SEQ_CHILD_ID AS n
   FROM t;
 

HSQLDB

For HSQLDB the generated SELECT will look something like this

 SELECT next value for seq_parent_id
   FROM UNNEST(SEQUENCE_ARRAY(1, ?, 1));
 

Oracle

For Oracle the generated SELECT will look something like this because Oracle does not support using recursive common table expressions to fetch multiple values from a sequence.

 SELECT seq_xxx.nextval
 FROM dual
 CONNECT BY rownum <= ?
 

SQL Server

For SQL Server the generated SELECT will look something like this

 WITH t(n) AS (
   SELECT 1 AS n
     UNION ALL
   SELECT n + 1 AS n
     FROM t
    WHERE n < ?)
 SELECT NEXT VALUE FOR seq_xxx AS n
   FROM t
 

Firebird

For Firebird the generated SELECT will look something like this

 WITH RECURSIVE t(n, level_num) AS (
   SELECT NEXT VALUE FOR seq_xxx AS n, 1 AS level_num
   FROM rdb$database
     UNION ALL
   SELECT NEXT VALUE FOR seq_xxx AS n, level_num + 1 AS level_num
     FROM t
    WHERE level_num < ?)
 SELECT n
   FROM t
 

Database Support

The following RDBMS have been verified to work

• DB2
• Firebird
• Oracle
• H2
• HSQLDB
• MariaDB
• Postgres
• SQL Sever

In theory any RDBMS that supports WITH RECURSIVE and sequences is supported.

For more details about how to use it, check out this article on vladmihalcea.com.

Since:

2.14.0

Author:

Philippe Marschall

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static final int	DEFAULT_FETCH_SIZE	The default value for FETCH_SIZE_PARAM.
static final String	FETCH_SIZE_PARAM	Deprecated. use BatchSequence
static final String	SEQUENCE_PARAM	Deprecated. use BatchSequence

Fields inherited from interface org.hibernate.id.IdentifierGenerator

CONTRIBUTOR_NAME, ENTITY_NAME, GENERATOR_NAME, JPA_ENTITY_NAME

Fields inherited from interface org.hibernate.id.OptimizableGenerator

DEFAULT_INCREMENT_SIZE, DEFAULT_INITIAL_VALUE, IMPLICIT_NAME_BASE, INCREMENT_PARAM, INITIAL_PARAM, OPT_PARAM

Fields inherited from interface org.hibernate.id.PersistentIdentifierGenerator

CATALOG, IDENTIFIER_NORMALIZER, PK, SCHEMA, TABLE, TABLES

Constructor Summary

Constructors

Constructor	Description
BatchSequenceGenerator(BatchSequence annotation, Member annotatedMember, org.hibernate.id.factory.spi.CustomIdGeneratorCreationContext context)	Called when BatchSequence is used.

Method Summary

Modifier and Type	Method	Description
void	configure(org.hibernate.type.Type type, Properties params, org.hibernate.service.ServiceRegistry serviceRegistry)
String	determineBulkInsertionIdentifierGenerationSelectFragment(org.hibernate.boot.model.relational.SqlStringGenerationContext sqlStringGenerationContext)
Serializable	generate(org.hibernate.engine.spi.SharedSessionContractImplementor session, Object object)
org.hibernate.id.enhanced.Optimizer	getOptimizer()
void	initialize(org.hibernate.boot.model.relational.SqlStringGenerationContext context)
void	registerExportables(org.hibernate.boot.model.relational.Database database)
boolean	supportsBulkInsertionIdentifierGeneration()
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.hibernate.generator.BeforeExecutionGenerator

generatedOnExecution

Methods inherited from interface org.hibernate.id.Configurable

create

Methods inherited from interface org.hibernate.generator.Generator

allowAssignedIdentifiers, generatedOnExecution, generatesOnInsert, generatesOnUpdate, generatesSometimes

Methods inherited from interface org.hibernate.id.IdentifierGenerator

generate, getEventTypes, supportsJdbcBatchInserts

Field Details

SEQUENCE_PARAM

@Deprecated
public static final String SEQUENCE_PARAM

Deprecated.

use BatchSequence

Indicates the name of the sequence to use, mandatory.

See Also:

• Constant Field Values

FETCH_SIZE_PARAM

@Deprecated
public static final String FETCH_SIZE_PARAM

Deprecated.

use BatchSequence

Indicates how many sequence values to fetch at once. The default value is DEFAULT_FETCH_SIZE.

See Also:

• Constant Field Values

DEFAULT_FETCH_SIZE

public static final int DEFAULT_FETCH_SIZE

The default value for FETCH_SIZE_PARAM.

See Also:

• Constant Field Values

Constructor Details

BatchSequenceGenerator

public BatchSequenceGenerator(BatchSequence annotation,
 Member annotatedMember,
 org.hibernate.id.factory.spi.CustomIdGeneratorCreationContext context)

Called when BatchSequence is used.

Parameters:

annotation - meta annotation for configuration

Method Details

configure

public void configure(org.hibernate.type.Type type,
 Properties params,
 org.hibernate.service.ServiceRegistry serviceRegistry)
               throws org.hibernate.MappingException

Specified by:

configure in interface org.hibernate.id.Configurable

Specified by:

configure in interface org.hibernate.id.IdentifierGenerator

Throws:

org.hibernate.MappingException

initialize

public void initialize(org.hibernate.boot.model.relational.SqlStringGenerationContext context)

Specified by:

initialize in interface org.hibernate.id.Configurable

supportsBulkInsertionIdentifierGeneration

public boolean supportsBulkInsertionIdentifierGeneration()

Specified by:

supportsBulkInsertionIdentifierGeneration in interface org.hibernate.id.BulkInsertionCapableIdentifierGenerator

determineBulkInsertionIdentifierGenerationSelectFragment

public String determineBulkInsertionIdentifierGenerationSelectFragment(org.hibernate.boot.model.relational.SqlStringGenerationContext sqlStringGenerationContext)

Specified by:

determineBulkInsertionIdentifierGenerationSelectFragment in interface org.hibernate.id.BulkInsertionCapableIdentifierGenerator

generate

public Serializable generate(org.hibernate.engine.spi.SharedSessionContractImplementor session,
 Object object)
                      throws org.hibernate.HibernateException

Specified by:

generate in interface org.hibernate.id.IdentifierGenerator

Throws:

org.hibernate.HibernateException

registerExportables

public void registerExportables(org.hibernate.boot.model.relational.Database database)

Specified by:

registerExportables in interface org.hibernate.boot.model.relational.ExportableProducer

Specified by:

registerExportables in interface org.hibernate.id.IdentifierGenerator

getOptimizer

public org.hibernate.id.enhanced.Optimizer getOptimizer()

Specified by:

getOptimizer in interface org.hibernate.id.OptimizableGenerator

toString

public String toString()

Overrides:

toString in class Object