Package io.hypersistence.utils.hibernate.id

Class BatchSequenceGenerator

java.lang.Object
io.hypersistence.utils.hibernate.id.BatchSequenceGenerator
All Implemented Interfaces:
org.hibernate.boot.model.relational.ExportableProducer, 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.

Parameters

The following configuration parameters are supported:
"sequence"
mandatory, name of the sequence to use
"fetch_size"
optional, how many sequence numbers should be fetched at a time, default is 10

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

  • 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
    Indicates how many sequence values to fetch at once.
    static final String
    SEQUENCE_PARAM
    Indicates the name of the sequence to use, mandatory.

    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()
     

  • 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.id.IdentifierGenerator

    supportsJdbcBatchInserts

  • Field Details

  • Constructor Details

    • BatchSequenceGenerator

      public BatchSequenceGenerator()

  • 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.IdentifierGenerator

    • 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