Question

我正在尝试使用Hibernate将Java日期存储在MariaDB中。似乎不同的日期被视为相同。例如：new Date(1518458441039)和new Date(1518458441102)显然是不同的日期，但两者都不能存储在声明为唯一的字段中：

11:09:59.540 [main] ERROR org.hibernate.engine.jdbc.spi.SqlExceptionHelper - (conn=502) Duplicate entry '2018-02-12 14:00:41' for key 'UK_plwo79yqbhw7h0yuxbrg5ru7q'
javax.persistence.PersistenceException: org.hibernate.exception.ConstraintViolationException: could not execute statement
        at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:147)
        at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:155)
        at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:162)
        at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:780)
        at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:758)
        at aero.navblue.ingest.MainClass$1.cacheMiss(MainClass.java:134)
        at aero.navblue.ingest.MainClass$1.cacheMiss(MainClass.java:122)
        at aero.navblue.CacheMap.get(CacheMap.java:13)
        at aero.navblue.ingest.MainClass.insertTimestamps(MainClass.java:144)
        at aero.navblue.ingest.MainClass.main(MainClass.java:73)
Caused by: org.hibernate.exception.ConstraintViolationException: could not execute statement
        at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:59)
        at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42)
        at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:111)
        at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:97)
        at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:208)
        at org.hibernate.dialect.identity.GetGeneratedKeysDelegate.executeAndExtract(GetGeneratedKeysDelegate.java:57)
        at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:42)
        at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2909)
        at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3480)
        at org.hibernate.action.internal.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:81)
        at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:623)
        at org.hibernate.engine.spi.ActionQueue.addResolvedEntityInsertAction(ActionQueue.java:277)
        at org.hibernate.engine.spi.ActionQueue.addInsertAction(ActionQueue.java:258)
        at org.hibernate.engine.spi.ActionQueue.addAction(ActionQueue.java:303)
        at org.hibernate.event.internal.AbstractSaveEventListener.addInsertAction(AbstractSaveEventListener.java:318)
        at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:275)
        at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:182)
        at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:113)
        at org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:189)
        at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:132)
        at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:58)
        at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:773)
        ... 6 more
Caused by: java.sql.SQLIntegrityConstraintViolationException: (conn=502) Duplicate entry '2018-02-12 14:00:41' for key 'UK_plwo79yqbhw7h0yuxbrg5ru7q'
        at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.get(ExceptionMapper.java:171)
        at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.getException(ExceptionMapper.java:110)
        at org.mariadb.jdbc.MariaDbStatement.executeExceptionEpilogue(MariaDbStatement.java:228)
        at org.mariadb.jdbc.MariaDbPreparedStatementClient.executeInternal(MariaDbPreparedStatementClient.java:216)
        at org.mariadb.jdbc.MariaDbPreparedStatementClient.execute(MariaDbPreparedStatementClient.java:150)
        at org.mariadb.jdbc.MariaDbPreparedStatementClient.executeUpdate(MariaDbPreparedStatementClient.java:183)
        at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:205)
        ... 23 more
Caused by: java.sql.SQLException: Duplicate entry '2018-02-12 14:00:41' for key 'UK_plwo79yqbhw7h0yuxbrg5ru7q'
Query is: insert into adsb_position_timestamp (create_date, create_user, modify_date, modify_user, position_received_time) values (?, ?, ?, ?, ?), parameters [<null>,<null>,<null>,<null>,'2018-02-12 14:00:41.102']
        at org.mariadb.jdbc.internal.util.LogQueryTool.exceptionWithQuery(LogQueryTool.java:153)
        at org.mariadb.jdbc.internal.protocol.AbstractQueryProtocol.executeQuery(AbstractQueryProtocol.java:254)
        at org.mariadb.jdbc.MariaDbPreparedStatementClient.executeInternal(MariaDbPreparedStatementClient.java:209)
        ... 26 more

然后将字段声明为：

@Temporal( TemporalType.TIMESTAMP )
@Column( name = "position_received_time", unique = true, nullable = false, length = 19, updatable = false )
public Date getPositionReceivedTime() {
    return this.positionReceivedTime;
}

Answer 1

如果您使用休眠创建数据库，则可以使用columnDefinition="DATETIME(3)"来启用分数支持。

@Temporal( TemporalType.TIMESTAMP )
@Column(columnDefinition="DATETIME(3)", name = "position_received_time", unique = true, nullable = false, length = 19, updatable = false )
public Date getPositionReceivedTime() {
    return this.positionReceivedTime;
}

否则，对于MariaDB，您可以使用：

CREATE TABLE example(
  col_microsec DATETIME(6),
  col_millisec TIME(3)
);

供参考，您可以阅读：microseconds-in-mariadb。

Hibernate和MariaDB只将时间戳存储到第二个精度？

1 个答案: