I'm having 2 Entities. Thread entity and Post entity using OnetoOne mapping from Post->Thread.
A Thread entity contains Numerous Posts. I know i should have used OnetoMany instead of OnetoOne, but for avoiding all the Collections problems i'm using OnetoOne
Now the problem is, when i delete a Thread, all the post associated with it must also be removed. I'm successful in doing it by using
@OnDelete(action = OnDeleteAction.CASCADE)
But it works only on Postgres and Ms-SQl but not on MySql(Tried InnoDb as well). The on delete cascade is not generated in the schema generation query.
Following are the code
//Thread Entity
@Id
@GeneratedValue
@Column(name = "thread_id")
private int ThreadID;
//Post Entity
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "post_id")
private int PostID;
@OneToOne()
@OnDelete(action = OnDeleteAction.CASCADE)
private thread ThreadID;
I get the following error While deleting an item from Thread entity using the following query
session.delete(session.load(thread.class,1));
Sep 02, 2014 8:33:51 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions WARN: SQL Error: 1451, SQLState: 23000 Sep 02, 2014 8:33:51 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions ERROR: Cannot delete or update a parent row: a foreign key constraint fails (
forum
.post_tbl
, CONSTRAINTFK_bfbv5nknqj7ppd5630scimhtb
FOREIGN KEY (ThreadID_thread_id
) REFERENCESthread_tbl
(thread_id
)) org.hibernate.exception.ConstraintViolationException: could not execute statement at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:74) at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49) at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:125) at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:110) at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:136) at org.hibernate.engine.jdbc.batch.internal.NonBatchingBatch.addToBatch(NonBatchingBatch.java:58) at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:3343) at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:3546) at org.hibernate.action.internal.EntityDeleteAction.execute(EntityDeleteAction.java:100) at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:377) at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:369) at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:293) at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:339) at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:52) at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1234) at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:404) at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.beforeTransactionCommit(JdbcTransaction.java:101) at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.commit(AbstractTransactionImpl.java:175) at test.main(test.java:84) Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot delete or update a parent row: a foreign key constraint fails (forum
.post_tbl
, CONSTRAINTFK_bfbv5nknqj7ppd5630scimhtb
FOREIGN KEY (ThreadID_thread_id
) REFERENCESthread_tbl
(thread_id
)) HibernateException : could not execute statement at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:408) at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) at com.mysql.jdbc.Util.getInstance(Util.java:386) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1040) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4120) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4052) at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2503) at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2664) at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2794) at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2155) at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2458) at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2375) at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2359) at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:133) ... 14 more BUILD SUCCESSFUL (total time: 2 seconds)
Please help me find a way out of this.
This is what I did to resolve this problem based on Spring Boot.
Solution
from
to
Explanation
As you can see below, it seems like the default value for CascadeDelete at MySQL5InnoDBDialect.java only support Cascade.