Hibernate JPA Sequence non-Id

Question

Is it possible to use a DB sequence for some column that is not the identifier is not part of a composite identifier    I m using hibernate as jpa provider  and I have a table that has some columns that are generated values  using a sequence   although they are not part of the identifier   What I want is to use a sequence to create a new value for an entity  where the column for the sequence is NOT  part of  the primary key    Entity  Table name    MyTable   public class MyEntity                   Id       etc     public Long getId             return id              note NO  Id here  but this doesn t work         GeneratedValue strategy   GenerationType AUTO  generator    myGen        SequenceGenerator name    myGen   sequenceName    MY SEQUENCE        Column name    SEQ VAL   unique   false  nullable   false  insertable   true  updatable   true      public Long getMySequencedValue          return myVal             Then when I do this   em persist new MyEntity       the id will be generated  but the mySequenceVal property will be also generated by my JPA provider   Just to make things clear  I want Hibernate to generate the value for the mySequencedValue property  I know Hibernate can handle database-generated values  but I don t want to use a trigger or any other thing other than Hibernate itself to generate the value for my property  If Hibernate can generate values for primary keys  why can t it generate for a simple property

User · Answer

I run in the same situation like you and I also didn't find any serious answers if it is basically possible to generate non-id propertys with JPA or not.

My solution is to call the sequence with a native JPA query to set the property by hand before persisiting it.

This is not satisfying but it works as a workaround for the moment.

Mario

User · Answer

After spending hours  this neatly helped me to solve my problem   For Oracle 12c   ID NUMBER GENERATED as IDENTITY   For H2   ID BIGINT GENERATED as auto increment   Also make    Column insertable   false

User · Answer

I ve been in a situation like you  JPA Hibernate sequence for non  Id field  and I ended up creating a trigger in my db schema that add a unique sequence number on insert  I just never got it to work with JPA Hibernate

User · Answer

I don t want to use a trigger or any other thing other than Hibernate itself to generate the value for my property   In that case  how about creating an implementation of UserType which generates the required value  and configuring the metadata to use that UserType for persistence of the mySequenceVal property

User · Answer

Looks like thread is old  I just wanted to add my solution here Using AspectJ - AOP in spring    Solution is to create a custom annotation  InjectSequenceValue as follows    Retention RetentionPolicy RUNTIME   Target ElementType FIELD  public  interface InjectSequenceValue       String sequencename        Now you can annotate any field in entity  so that the underlying field  Long Integer  value will be injected at runtime using the nextvalue of the sequence   Annotate like this     serialNumber will be injected dynamically  with the next value of the serialnum sequence    InjectSequenceValue sequencename    serialnum sequence      Long serialNumber    So far we have marked the field we need to inject the sequence value So we will look how to inject the sequence value to the marked fields  this is done by creating the point cut in AspectJ   We will trigger the injection just before the save persist method is being executed This is done in the below class    Aspect  Configuration public class AspectDefinition         Autowired     JdbcTemplate jdbcTemplate           Before  execution   org hibernate session save        Use this for Hibernate  also include session save         Before  execution   org springframework data repository CrudRepository save          This is for JPA      public void generateSequence JoinPoint joinPoint            Object    aragumentList joinPoint getArgs      Getting all arguments of the save         for  Object arg  aragumentList                 if  arg getClass   isAnnotationPresent Entity class       getting the Entity class                  Field   fields   arg getClass   getDeclaredFields                    for  Field field   fields                        if  field isAnnotationPresent InjectSequenceValue class       getting annotated fields                          field setAccessible true                            try                               if  field get arg     null      Setting the next value                                 String sequenceName field getAnnotation InjectSequenceValue class  sequencename                                    long nextval getNextValue sequenceName                                   System out println  Next value    nextval     TODO remove sout                                  field set arg  nextval                                                            catch  Exception e                                e printStackTrace                                                                                                                     This method fetches the next value from sequence         param sequence         return              public long getNextValue String sequence           long sequenceNextVal 0L           SqlRowSet sqlRowSet  jdbcTemplate queryForRowSet  SELECT   sequence   NEXTVAL as value FROM DUAL            while  sqlRowSet next                 sequenceNextVal sqlRowSet getLong  value                       return  sequenceNextVal            Now you can annotate any Entity as below    Entity  Table name    T USER   public class UserEntity         Id      SequenceGenerator sequenceName    userid sequence  name    this seq        GeneratedValue strategy   GenerationType SEQUENCE generator    this seq       Long id      String userName      String password        InjectSequenceValue sequencename    serialnum sequence      this will be injected at the time of saving      Long serialNumber       String name

User · Answer

If you are using postgresql  And i m using in spring boot 1 5 6   Column columnDefinition    serial    Generated GenerationTime INSERT  private Integer orderID

User · Answer

This is not the same as using a sequence   When using a sequence  you are not inserting or updating anything   You are simply retrieving the next sequence value   It looks like hibernate does not support it

User · Answer

I run in the same situation like you and I also didn't find any serious answers if it is basically possible to generate non-id propertys with JPA or not.

My solution is to call the sequence with a native JPA query to set the property by hand before persisiting it.

This is not satisfying but it works as a workaround for the moment.

Mario

User · Answer

Hibernate definitely supports this  From the docs    Generated properties are properties which have their values generated by the database  Typically  Hibernate applications needed to refresh  objects which contain any properties for which the database was generating values  Marking properties as generated  however  lets the application delegate this responsibility to Hibernate  Essentially  whenever Hibernate issues an SQL INSERT or UPDATE for an entity which has defined generated properties  it immediately issues a select afterwards to retrieve the generated values    For properties generated on insert only  your property mapping   hbm xml  would look like    lt property name  foo  generated  insert   gt    For properties generated on insert and update your property mapping   hbm xml  would look like    lt property name  foo  generated  always   gt    Unfortunately  I don t know JPA  so I don t know if this feature is exposed via JPA  I suspect possibly not   Alternatively  you should be able to exclude the property from inserts and updates  and then  manually  call session refresh  obj    after you have inserted updated it to load the generated value from the database   This is how you would exclude the property from being used in insert and update statements    lt property name  foo  update  false  insert  false   gt    Again  I don t know if JPA exposes these Hibernate features  but Hibernate does support them

User · Answer

As a followup here s how I got it to work    Override public Long getNextExternalId         BigDecimal seq            BigDecimal   List em createNativeQuery  select col msd external id seq nextval from dual   getResultList    get 0       return seq longValue

User · Answer

I was struggling with this today  was able to solve using this  Generated GenerationTime INSERT   Column name    quot internal id quot   columnDefinition    quot serial quot   updatable   false  private int internalId

User · Answer

Although this is an old thread I want to share my solution and hopefully get some feedback on this  Be warned that I only tested this solution with my local database in some JUnit testcase  So this is not a productive feature so far   I solved that issue for my by introducing a custom annotation called Sequence with no property  It s just a marker for fields that should be assigned a value from an incremented sequence    Retention RetentionPolicy RUNTIME   Target ElementType FIELD  public  interface Sequence       Using this annotation i marked my entities   public class Area extends BaseEntity implements ClientAware  IssuerAware        Column name    areaNumber   updatable   false       Sequence     private Integer areaNumber           To keep things database independent I introduced an entity called SequenceNumber which holds the sequence current value and the increment size  I chose the className as unique key so each entity class wil get its own sequence    Entity  Table name    SequenceNumber   uniqueConstraints      UniqueConstraint columnNames      className        public class SequenceNumber        Id      Column name    className   updatable   false      private String className        Column name    nextValue       private Integer nextValue   1        Column name    incrementValue       private Integer incrementValue   10           some getters and setters          The last step and the most difficult is a PreInsertListener that handles the sequence number assignment  Note that I used spring as bean container    Component public class SequenceListener implements PreInsertEventListener       private static final long serialVersionUID   7946581162328559098L      private final static Logger log   Logger getLogger SequenceListener class         Autowired     private SessionFactoryImplementor sessionFactoryImpl       private final Map lt String  CacheEntry gt  cache   new HashMap lt  gt           PostConstruct     public void selfRegister                    As you might expect  an EventListenerRegistry is the place with which event listeners are registered            It is a service so we look it up using the service registry         final EventListenerRegistry eventListenerRegistry   sessionFactoryImpl getServiceRegistry   getService EventListenerRegistry class               add the listener to the end of the listener chain         eventListenerRegistry appendListeners EventType PRE INSERT  this               Override     public boolean onPreInsert PreInsertEvent p event                updateSequenceValue p event getEntity    p event getState    p event getPersister   getPropertyNames              return false             private void updateSequenceValue Object p entity  Object   p state  String   p propertyNames                try                       List lt Field gt  fields   ReflectUtil getFields p entity getClass    null  Sequence class                if   fields isEmpty                                  if  log isDebugEnabled                                          log debug  Intercepted custom sequence entity                                        for  Field field   fields                                        Integer value   getSequenceNumber p entity getClass   getName                          field setAccessible true                       field set p entity  value                       setPropertyState p state  p propertyNames  field getName    value                        if  log isDebugEnabled                                                  LogMF debug log   Set  0  property to  1     new Object     field  value                                                                             catch  Exception e                        log error  Failed to set sequence property    e                        private Integer getSequenceNumber String p className                synchronized  cache                        CacheEntry current   cache get p className                   not in cache yet   gt  load from database             if   current    null     current isEmpty                                  boolean insert   false                  StatelessSession session   sessionFactoryImpl openStatelessSession                    session beginTransaction                     SequenceNumber sequenceNumber    SequenceNumber  session get SequenceNumber class  p className                       not in database yet   gt  create new sequence                 if  sequenceNumber    null                                        sequenceNumber   new SequenceNumber                        sequenceNumber setClassName p className                       insert   true                                     current   new CacheEntry sequenceNumber getNextValue     sequenceNumber getIncrementValue    sequenceNumber getNextValue                     cache put p className  current                   sequenceNumber setNextValue sequenceNumber getNextValue     sequenceNumber getIncrementValue                      if  insert                                        session insert sequenceNumber                                     else                                       session update sequenceNumber                                     session getTransaction   commit                    session close                               return current next                         private void setPropertyState Object   propertyStates  String   propertyNames  String propertyName  Object propertyState                for  int i   0  i  lt  propertyNames length  i                          if  propertyName equals propertyNames i                                  propertyStates i    propertyState                  return                                     private static class CacheEntry               private int current          private final int limit           public CacheEntry final int p limit  final int p current                        current   p current              limit   p limit                     public Integer next                         return current                       public boolean isEmpty                         return current  gt   limit                      As you can see from the above code the listener used one SequenceNumber instance per entity class and reserves a couple of sequence numbers defined by the incrementValue of the SequenceNumber entity  If it runs out of sequence numbers it loads the SequenceNumber entity for the target class and reserves incrementValue values for the next calls  This way I do not need to query the database each time a sequence value is needed  Note the StatelessSession that is being opened for reserving the next set of sequence numbers  You cannot use the same session the target entity is currently persisted since this would lead to a ConcurrentModificationException in the EntityPersister   Hope this helps someone

User · Answer

I was struggling with this today  was able to solve using this  Generated GenerationTime INSERT   Column name    quot internal id quot   columnDefinition    quot serial quot   updatable   false  private int internalId

User · Answer

This is not the same as using a sequence   When using a sequence  you are not inserting or updating anything   You are simply retrieving the next sequence value   It looks like hibernate does not support it

User · Answer

Looks like thread is old  I just wanted to add my solution here Using AspectJ - AOP in spring    Solution is to create a custom annotation  InjectSequenceValue as follows    Retention RetentionPolicy RUNTIME   Target ElementType FIELD  public  interface InjectSequenceValue       String sequencename        Now you can annotate any field in entity  so that the underlying field  Long Integer  value will be injected at runtime using the nextvalue of the sequence   Annotate like this     serialNumber will be injected dynamically  with the next value of the serialnum sequence    InjectSequenceValue sequencename    serialnum sequence      Long serialNumber    So far we have marked the field we need to inject the sequence value So we will look how to inject the sequence value to the marked fields  this is done by creating the point cut in AspectJ   We will trigger the injection just before the save persist method is being executed This is done in the below class    Aspect  Configuration public class AspectDefinition         Autowired     JdbcTemplate jdbcTemplate           Before  execution   org hibernate session save        Use this for Hibernate  also include session save         Before  execution   org springframework data repository CrudRepository save          This is for JPA      public void generateSequence JoinPoint joinPoint            Object    aragumentList joinPoint getArgs      Getting all arguments of the save         for  Object arg  aragumentList                 if  arg getClass   isAnnotationPresent Entity class       getting the Entity class                  Field   fields   arg getClass   getDeclaredFields                    for  Field field   fields                        if  field isAnnotationPresent InjectSequenceValue class       getting annotated fields                          field setAccessible true                            try                               if  field get arg     null      Setting the next value                                 String sequenceName field getAnnotation InjectSequenceValue class  sequencename                                    long nextval getNextValue sequenceName                                   System out println  Next value    nextval     TODO remove sout                                  field set arg  nextval                                                            catch  Exception e                                e printStackTrace                                                                                                                     This method fetches the next value from sequence         param sequence         return              public long getNextValue String sequence           long sequenceNextVal 0L           SqlRowSet sqlRowSet  jdbcTemplate queryForRowSet  SELECT   sequence   NEXTVAL as value FROM DUAL            while  sqlRowSet next                 sequenceNextVal sqlRowSet getLong  value                       return  sequenceNextVal            Now you can annotate any Entity as below    Entity  Table name    T USER   public class UserEntity         Id      SequenceGenerator sequenceName    userid sequence  name    this seq        GeneratedValue strategy   GenerationType SEQUENCE generator    this seq       Long id      String userName      String password        InjectSequenceValue sequencename    serialnum sequence      this will be injected at the time of saving      Long serialNumber       String name

User · Answer

I fixed the generation of UUID  or sequences  with Hibernate using  PrePersist annotation    PrePersist public void initializeUUID         if  uuid    null            uuid   UUID randomUUID   toString

User · Answer

I want to provide an alternative next to  Morten Berg s accepted solution  which worked better for me   This approach allows to define the field with the actually desired Number type - Long in my use case - instead of GeneralSequenceNumber  This can be useful  e g  for JSON  de- serialization   The downside is that it requires a little more database overhead     First  we need an ActualEntity in which we want to auto-increment generated of type Long           Entity public class ActualEntity         Id                 Long id        Column unique   true  updatable   false  nullable   false      Long generated                   Next  we need a helper entity Generated  I placed it package-private next to ActualEntity  to keep it an implementation detail of the package    Entity class Generated         Id      GeneratedValue strategy   SEQUENCE  generator    seq        SequenceGenerator name    seq   initialValue   1  allocationSize   1      Long id       Finally  we need a place to hook in right before we save the ActualEntity  There  we create and persist aGenerated instance  This then provides a database-sequence generated id of type Long  We make use of this value by writing it to ActualEntity generated    In my use case  I implemented this using a Spring Data REST  RepositoryEventHandler  which get s called right before the ActualEntity get s persisted  It should demonstrate the principle    Component  RepositoryEventHandler public class ActualEntityHandler         Autowired     EntityManager entityManager        Transactional      HandleBeforeCreate     public void generate ActualEntity entity            Generated generated   new Generated             entityManager persist generated           entity setGlobalId generated getId             entityManager remove generated              I didn t test it in a real-life application  so please enjoy with care

User · Answer

I don t want to use a trigger or any other thing other than Hibernate itself to generate the value for my property   In that case  how about creating an implementation of UserType which generates the required value  and configuring the metadata to use that UserType for persistence of the mySequenceVal property

User · Answer

I found that  Column columnDefinition  quot serial quot   works perfect but only for PostgreSQL  For me this was perfect solution  because second entity is  quot ugly quot  option  A call to saveAndFlush on the entity is also necessary  and save won t be enough to populate the value from the DB

User · Answer

After spending hours  this neatly helped me to solve my problem   For Oracle 12c   ID NUMBER GENERATED as IDENTITY   For H2   ID BIGINT GENERATED as auto increment   Also make    Column insertable   false

User · Answer

I run in the same situation like you and I also didn't find any serious answers if it is basically possible to generate non-id propertys with JPA or not.

My solution is to call the sequence with a native JPA query to set the property by hand before persisiting it.

This is not satisfying but it works as a workaround for the moment.

Mario

User · Answer

I ve found this specific note in session 9 1 9 GeneratedValue Annotation from JPA specification    43  Portable applications should not use the GeneratedValue annotation on other persistent fields or properties   So  I presume that it is not possible to auto generate value for non primary key values at least using simply JPA

User · Answer

I don t want to use a trigger or any other thing other than Hibernate itself to generate the value for my property   In that case  how about creating an implementation of UserType which generates the required value  and configuring the metadata to use that UserType for persistence of the mySequenceVal property

User · Answer

I ve been in a situation like you  JPA Hibernate sequence for non  Id field  and I ended up creating a trigger in my db schema that add a unique sequence number on insert  I just never got it to work with JPA Hibernate

User · Answer

I have found a workaround for this on MySql databases using  PostConstruct and JdbcTemplate in a Spring application  It may be doable with other databases but the use case that I will present is based on my experience with MySql  as it uses auto increment     First  I had tried defining a column as auto increment using the ColumnDefinition property of the  Column annotation  but it was not working as the column needed to be an key in order to be auto incremental  but apparently the column wouldn t be defined as an index until after it was defined  causing a deadlock     Here is where I came with the idea of creating the column without the auto increment definition  and adding it after the database was created  This is possible using the  PostConstruct annotation  which causes a method to be invoked right after the application has initialized the beans  coupled with JdbcTemplate s update method     The code is as follows     In My Entity      Entity  Table name    MyTable   indexes      Index name    my index   columnList    mySequencedValue      public class MyEntity                  Column columnDefinition    integer unsigned   nullable   false  updatable   false  insertable   false      private Long mySequencedValue                In a PostConstructComponent class      Component public class PostConstructComponent        Autowired     private JdbcTemplate jdbcTemplate        PostConstruct     public void makeMyEntityMySequencedValueAutoIncremental             jdbcTemplate update  alter table MyTable modify mySequencedValue int unsigned auto increment

User · Answer

I ve been in a situation like you  JPA Hibernate sequence for non  Id field  and I ended up creating a trigger in my db schema that add a unique sequence number on insert  I just never got it to work with JPA Hibernate

User · Answer

I want to provide an alternative next to  Morten Berg s accepted solution  which worked better for me   This approach allows to define the field with the actually desired Number type - Long in my use case - instead of GeneralSequenceNumber  This can be useful  e g  for JSON  de- serialization   The downside is that it requires a little more database overhead     First  we need an ActualEntity in which we want to auto-increment generated of type Long           Entity public class ActualEntity         Id                 Long id        Column unique   true  updatable   false  nullable   false      Long generated                   Next  we need a helper entity Generated  I placed it package-private next to ActualEntity  to keep it an implementation detail of the package    Entity class Generated         Id      GeneratedValue strategy   SEQUENCE  generator    seq        SequenceGenerator name    seq   initialValue   1  allocationSize   1      Long id       Finally  we need a place to hook in right before we save the ActualEntity  There  we create and persist aGenerated instance  This then provides a database-sequence generated id of type Long  We make use of this value by writing it to ActualEntity generated    In my use case  I implemented this using a Spring Data REST  RepositoryEventHandler  which get s called right before the ActualEntity get s persisted  It should demonstrate the principle    Component  RepositoryEventHandler public class ActualEntityHandler         Autowired     EntityManager entityManager        Transactional      HandleBeforeCreate     public void generate ActualEntity entity            Generated generated   new Generated             entityManager persist generated           entity setGlobalId generated getId             entityManager remove generated              I didn t test it in a real-life application  so please enjoy with care

User · Answer

As a followup here s how I got it to work    Override public Long getNextExternalId         BigDecimal seq            BigDecimal   List em createNativeQuery  select col msd external id seq nextval from dual   getResultList    get 0       return seq longValue

User · Answer

I found that  Column columnDefinition  quot serial quot   works perfect but only for PostgreSQL  For me this was perfect solution  because second entity is  quot ugly quot  option  A call to saveAndFlush on the entity is also necessary  and save won t be enough to populate the value from the DB

User · Answer

Hibernate definitely supports this  From the docs    Generated properties are properties which have their values generated by the database  Typically  Hibernate applications needed to refresh  objects which contain any properties for which the database was generating values  Marking properties as generated  however  lets the application delegate this responsibility to Hibernate  Essentially  whenever Hibernate issues an SQL INSERT or UPDATE for an entity which has defined generated properties  it immediately issues a select afterwards to retrieve the generated values    For properties generated on insert only  your property mapping   hbm xml  would look like    lt property name  foo  generated  insert   gt    For properties generated on insert and update your property mapping   hbm xml  would look like    lt property name  foo  generated  always   gt    Unfortunately  I don t know JPA  so I don t know if this feature is exposed via JPA  I suspect possibly not   Alternatively  you should be able to exclude the property from inserts and updates  and then  manually  call session refresh  obj    after you have inserted updated it to load the generated value from the database   This is how you would exclude the property from being used in insert and update statements    lt property name  foo  update  false  insert  false   gt    Again  I don t know if JPA exposes these Hibernate features  but Hibernate does support them

User · Answer

I know this is a very old question  but it s showed firstly upon the results and jpa has changed a lot since the question   The right way to do it now is with the  Generated annotation  You can define the sequence  set the default in the column to that sequence and then map the column as    Generated GenerationTime INSERT   Column name    column name   insertable   false

User · Answer

I ve been in a situation like you  JPA Hibernate sequence for non  Id field  and I ended up creating a trigger in my db schema that add a unique sequence number on insert  I just never got it to work with JPA Hibernate

User · Answer

Although this is an old thread I want to share my solution and hopefully get some feedback on this  Be warned that I only tested this solution with my local database in some JUnit testcase  So this is not a productive feature so far   I solved that issue for my by introducing a custom annotation called Sequence with no property  It s just a marker for fields that should be assigned a value from an incremented sequence    Retention RetentionPolicy RUNTIME   Target ElementType FIELD  public  interface Sequence       Using this annotation i marked my entities   public class Area extends BaseEntity implements ClientAware  IssuerAware        Column name    areaNumber   updatable   false       Sequence     private Integer areaNumber           To keep things database independent I introduced an entity called SequenceNumber which holds the sequence current value and the increment size  I chose the className as unique key so each entity class wil get its own sequence    Entity  Table name    SequenceNumber   uniqueConstraints      UniqueConstraint columnNames      className        public class SequenceNumber        Id      Column name    className   updatable   false      private String className        Column name    nextValue       private Integer nextValue   1        Column name    incrementValue       private Integer incrementValue   10           some getters and setters          The last step and the most difficult is a PreInsertListener that handles the sequence number assignment  Note that I used spring as bean container    Component public class SequenceListener implements PreInsertEventListener       private static final long serialVersionUID   7946581162328559098L      private final static Logger log   Logger getLogger SequenceListener class         Autowired     private SessionFactoryImplementor sessionFactoryImpl       private final Map lt String  CacheEntry gt  cache   new HashMap lt  gt           PostConstruct     public void selfRegister                    As you might expect  an EventListenerRegistry is the place with which event listeners are registered            It is a service so we look it up using the service registry         final EventListenerRegistry eventListenerRegistry   sessionFactoryImpl getServiceRegistry   getService EventListenerRegistry class               add the listener to the end of the listener chain         eventListenerRegistry appendListeners EventType PRE INSERT  this               Override     public boolean onPreInsert PreInsertEvent p event                updateSequenceValue p event getEntity    p event getState    p event getPersister   getPropertyNames              return false             private void updateSequenceValue Object p entity  Object   p state  String   p propertyNames                try                       List lt Field gt  fields   ReflectUtil getFields p entity getClass    null  Sequence class                if   fields isEmpty                                  if  log isDebugEnabled                                          log debug  Intercepted custom sequence entity                                        for  Field field   fields                                        Integer value   getSequenceNumber p entity getClass   getName                          field setAccessible true                       field set p entity  value                       setPropertyState p state  p propertyNames  field getName    value                        if  log isDebugEnabled                                                  LogMF debug log   Set  0  property to  1     new Object     field  value                                                                             catch  Exception e                        log error  Failed to set sequence property    e                        private Integer getSequenceNumber String p className                synchronized  cache                        CacheEntry current   cache get p className                   not in cache yet   gt  load from database             if   current    null     current isEmpty                                  boolean insert   false                  StatelessSession session   sessionFactoryImpl openStatelessSession                    session beginTransaction                     SequenceNumber sequenceNumber    SequenceNumber  session get SequenceNumber class  p className                       not in database yet   gt  create new sequence                 if  sequenceNumber    null                                        sequenceNumber   new SequenceNumber                        sequenceNumber setClassName p className                       insert   true                                     current   new CacheEntry sequenceNumber getNextValue     sequenceNumber getIncrementValue    sequenceNumber getNextValue                     cache put p className  current                   sequenceNumber setNextValue sequenceNumber getNextValue     sequenceNumber getIncrementValue                      if  insert                                        session insert sequenceNumber                                     else                                       session update sequenceNumber                                     session getTransaction   commit                    session close                               return current next                         private void setPropertyState Object   propertyStates  String   propertyNames  String propertyName  Object propertyState                for  int i   0  i  lt  propertyNames length  i                          if  propertyName equals propertyNames i                                  propertyStates i    propertyState                  return                                     private static class CacheEntry               private int current          private final int limit           public CacheEntry final int p limit  final int p current                        current   p current              limit   p limit                     public Integer next                         return current                       public boolean isEmpty                         return current  gt   limit                      As you can see from the above code the listener used one SequenceNumber instance per entity class and reserves a couple of sequence numbers defined by the incrementValue of the SequenceNumber entity  If it runs out of sequence numbers it loads the SequenceNumber entity for the target class and reserves incrementValue values for the next calls  This way I do not need to query the database each time a sequence value is needed  Note the StatelessSession that is being opened for reserving the next set of sequence numbers  You cannot use the same session the target entity is currently persisted since this would lead to a ConcurrentModificationException in the EntityPersister   Hope this helps someone

User · Answer

Hibernate definitely supports this  From the docs    Generated properties are properties which have their values generated by the database  Typically  Hibernate applications needed to refresh  objects which contain any properties for which the database was generating values  Marking properties as generated  however  lets the application delegate this responsibility to Hibernate  Essentially  whenever Hibernate issues an SQL INSERT or UPDATE for an entity which has defined generated properties  it immediately issues a select afterwards to retrieve the generated values    For properties generated on insert only  your property mapping   hbm xml  would look like    lt property name  foo  generated  insert   gt    For properties generated on insert and update your property mapping   hbm xml  would look like    lt property name  foo  generated  always   gt    Unfortunately  I don t know JPA  so I don t know if this feature is exposed via JPA  I suspect possibly not   Alternatively  you should be able to exclude the property from inserts and updates  and then  manually  call session refresh  obj    after you have inserted updated it to load the generated value from the database   This is how you would exclude the property from being used in insert and update statements    lt property name  foo  update  false  insert  false   gt    Again  I don t know if JPA exposes these Hibernate features  but Hibernate does support them

User · Answer

I know this is a very old question  but it s showed firstly upon the results and jpa has changed a lot since the question   The right way to do it now is with the  Generated annotation  You can define the sequence  set the default in the column to that sequence and then map the column as    Generated GenerationTime INSERT   Column name    column name   insertable   false

User · Answer

I don t want to use a trigger or any other thing other than Hibernate itself to generate the value for my property   In that case  how about creating an implementation of UserType which generates the required value  and configuring the metadata to use that UserType for persistence of the mySequenceVal property

User · Answer

I have found a workaround for this on MySql databases using  PostConstruct and JdbcTemplate in a Spring application  It may be doable with other databases but the use case that I will present is based on my experience with MySql  as it uses auto increment     First  I had tried defining a column as auto increment using the ColumnDefinition property of the  Column annotation  but it was not working as the column needed to be an key in order to be auto incremental  but apparently the column wouldn t be defined as an index until after it was defined  causing a deadlock     Here is where I came with the idea of creating the column without the auto increment definition  and adding it after the database was created  This is possible using the  PostConstruct annotation  which causes a method to be invoked right after the application has initialized the beans  coupled with JdbcTemplate s update method     The code is as follows     In My Entity      Entity  Table name    MyTable   indexes      Index name    my index   columnList    mySequencedValue      public class MyEntity                  Column columnDefinition    integer unsigned   nullable   false  updatable   false  insertable   false      private Long mySequencedValue                In a PostConstructComponent class      Component public class PostConstructComponent        Autowired     private JdbcTemplate jdbcTemplate        PostConstruct     public void makeMyEntityMySequencedValueAutoIncremental             jdbcTemplate update  alter table MyTable modify mySequencedValue int unsigned auto increment

User · Answer

If you have a column with UNIQUEIDENTIFIER type and default generation needed on insert but column is not PK    Generated GenerationTime INSERT   Column nullable   false   columnDefinition  UNIQUEIDENTIFIER   private String uuidValue    In db you will have   CREATE TABLE operation Table1       Id         INT IDENTITY  1 1                NOT NULL      UuidValue  UNIQUEIDENTIFIER DEFAULT NEWID   NOT NULL    In this case you will not define generator for a value which you need  It will be automatically thanks to  columnDefinition  UNIQUEIDENTIFIER    The same you can try for other column types

User · Answer

Hibernate definitely supports this  From the docs    Generated properties are properties which have their values generated by the database  Typically  Hibernate applications needed to refresh  objects which contain any properties for which the database was generating values  Marking properties as generated  however  lets the application delegate this responsibility to Hibernate  Essentially  whenever Hibernate issues an SQL INSERT or UPDATE for an entity which has defined generated properties  it immediately issues a select afterwards to retrieve the generated values    For properties generated on insert only  your property mapping   hbm xml  would look like    lt property name  foo  generated  insert   gt    For properties generated on insert and update your property mapping   hbm xml  would look like    lt property name  foo  generated  always   gt    Unfortunately  I don t know JPA  so I don t know if this feature is exposed via JPA  I suspect possibly not   Alternatively  you should be able to exclude the property from inserts and updates  and then  manually  call session refresh  obj    after you have inserted updated it to load the generated value from the database   This is how you would exclude the property from being used in insert and update statements    lt property name  foo  update  false  insert  false   gt    Again  I don t know if JPA exposes these Hibernate features  but Hibernate does support them

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If you are using postgresql  And i m using in spring boot 1 5 6   Column columnDefinition    serial    Generated GenerationTime INSERT  private Integer orderID

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I ve found this specific note in session 9 1 9 GeneratedValue Annotation from JPA specification    43  Portable applications should not use the GeneratedValue annotation on other persistent fields or properties   So  I presume that it is not possible to auto generate value for non primary key values at least using simply JPA

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Looking for answers to this problem  I stumbled upon this link  It seems that Hibernate JPA isn t able to automatically create a value for your non-id-properties  The  GeneratedValue annotation is only used in conjunction with  Id to create auto-numbers   The  GeneratedValue annotation just tells Hibernate that the database is generating this value itself   The solution  or work-around  suggested in that forum is to create a separate entity with a generated Id  something like this     Entity public class GeneralSequenceNumber      Id    GeneratedValue        private Long number      Entity  public class MyEntity      Id      private Long id      OneToOne        private GeneralSequnceNumber myVal

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Looking for answers to this problem  I stumbled upon this link  It seems that Hibernate JPA isn t able to automatically create a value for your non-id-properties  The  GeneratedValue annotation is only used in conjunction with  Id to create auto-numbers   The  GeneratedValue annotation just tells Hibernate that the database is generating this value itself   The solution  or work-around  suggested in that forum is to create a separate entity with a generated Id  something like this     Entity public class GeneralSequenceNumber      Id    GeneratedValue        private Long number      Entity  public class MyEntity      Id      private Long id      OneToOne        private GeneralSequnceNumber myVal

User · Answer

If you have a column with UNIQUEIDENTIFIER type and default generation needed on insert but column is not PK    Generated GenerationTime INSERT   Column nullable   false   columnDefinition  UNIQUEIDENTIFIER   private String uuidValue    In db you will have   CREATE TABLE operation Table1       Id         INT IDENTITY  1 1                NOT NULL      UuidValue  UNIQUEIDENTIFIER DEFAULT NEWID   NOT NULL    In this case you will not define generator for a value which you need  It will be automatically thanks to  columnDefinition  UNIQUEIDENTIFIER    The same you can try for other column types

User · Answer

I fixed the generation of UUID  or sequences  with Hibernate using  PrePersist annotation    PrePersist public void initializeUUID         if  uuid    null            uuid   UUID randomUUID   toString

User · Answer

I run in the same situation like you and I also didn't find any serious answers if it is basically possible to generate non-id propertys with JPA or not.

My solution is to call the sequence with a native JPA query to set the property by hand before persisiting it.

This is not satisfying but it works as a workaround for the moment.

Mario

[java] Hibernate JPA Sequence (non-Id)

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