Question

我有以下问题。我有2个实体，电影和演员。

电影有多个演员，但演员可以在多部电影中。现在，当我试图添加两部具有共同角色的电影时，问题就出现了。

我们假设我添加了死区，之后我添加了死区2.当我添加第二部电影时，我收到以下错误：

语句已中止，因为它会在唯一或主键约束中导致重复键值

现在这是有效的，因为jpa正在将actor插入已存在的数据库中。我不知道如何解决这个问题，我从TheMovieDatabase获取了ID，我不希望在我的数据库中有重复的Actors。

MOVIE：

@Entity(name = "Movie")
public class Movie {

//instance variables
@Positive
@Id
private long tmdbId;

...

@ManyToMany(cascade = {CascadeType.PERSIST, CascadeType.MERGE})
@JoinTable(name = "movie_actor",
        joinColumns = @JoinColumn(name = "movie_tmdbid"),
        inverseJoinColumns = @JoinColumn(name = "actor_id")
)
private Set<Actor> actors = new HashSet<>();

...

演员：

@Entity(name = "Actor")
public class Actor {

@Id
private long id;

...

@ManyToMany(mappedBy = "actors")
private Set<Movie> movies = new HashSet<>();

Jpa添加方法

    public void addMovie(Movie movie) {
    try {
        //open connection
        openConnection();

        //check
        if (movie == null) {
            throw new DatabaseException("You cannot add an empty movie");
        }

        //contains only looks in the current persistence context
        if (entityManager.find(Movie.class,movie.getTmdbId()) != null) {
            throw new MovieAlreadyExistsException("This movie already exists!");
        }

        //begin transaction
        entityManager.getTransaction().begin();

        //add movie & commit
        entityManager.persist(movie);
        entityManager.getTransaction().commit();

    }catch (MovieAlreadyExistsException error){
        throw new MovieAlreadyExistsException(error.getMessage(),error);
    } catch (Exception error) {
        throw new DatabaseException(error.getMessage(), error);
    } finally {
        closeConnection();
    }
}

设置演员的方法：来自TheMovieDatabase的演员和addMovie是来自幕后的jpa的演员。

//add a movie
@PostMapping(value = "/add")
public String saveMovie(@ModelAttribute("movie") @Valid Movie movie, BindingResult result) {
    ...

    try{
            //set actors
        Set<Actor> actors = new HashSet<>(mediaService.getMovieActors(movie.getTmdbId()));
        movie.setActors(actors);

        //add movie with actors
        movieService.addMovie(movie);

堆栈跟踪：

内部异常：org.apache.derby.shared.common.error.DerbySQLIntegrityConstraintViolationException：语句已中止，因为它会在唯一或主键约束或由＆＃39; SQL180530224955890＆标识的唯一索引中导致重复键值＃39;定义于＆＃39; ACTOR＆＃39;。错误代码：20000 致电：插入ACTOR（ID，MOVIECHARACTER，NAME，PROFILEPICTURE）值（？，？，？，？） bind =＆gt; [4个参数绑定] 查询：具有根本原因的InsertObjectQuery（model.movie.actor.Actor@d681）] 错误23505：语句已中止，因为它会在唯一或主键约束或由＆＃39; SQL180530224955890＆＃39;标识的唯一索引中导致重复键值。定义于＆＃39; ACTOR＆＃39;。 at org.apache.derby.client.am.ClientStatement.completeExecute（Unknown Source）在org.apache.derby.client.net.NetStatementReply.parseEXCSQLSTTreply（未知来源）在org.apache.derby.client.net.NetStatementReply.readExecute（未知来源）在org.apache.derby.client.net.StatementReply.readExecute（未知来源） at org.apache.derby.client.net.NetPreparedStatement.readExecute_（未知来源） at org.apache.derby.client.am.ClientPreparedStatement.readExecute（Unknown Source） at org.apache.derby.client.am.ClientPreparedStatement.flowExecute（Unknown Source）在org.apache.derby.client.am.ClientPreparedStatement.executeUpdateX（未知来源）在org.apache.derby.client.am.ClientPreparedStatement.executeUpdate（未知来源）在org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeDirectNoSelect（DatabaseAccessor.java:895）在org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeNoSelect（DatabaseAccessor.java:967）在org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.basicExecuteCall（DatabaseAccessor.java:637）在org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeCall（DatabaseAccessor.java:564） at org.eclipse.persistence.internal.sessions.AbstractSession.basicExecuteCall（AbstractSession.java:2093）在org.eclipse.persistence.sessions.server.ClientSession.executeCall（ClientSession.java:309）在org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall（DatasourceCallQueryMechanism.java:270）在org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall（DatasourceCallQueryMechanism.java:256）在org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.insertObject（DatasourceCallQueryMechanism.java:405） at org.eclipse.persistence.internal.queries.StatementQueryMechanism.insertObject（StatementQueryMechanism.java:165） at org.eclipse.persistence.internal.queries.StatementQueryMechanism.insertObject（StatementQueryMechanism.java:180）在org.eclipse.persistence.internal.queries.DatabaseQueryMechanism.insertObjectForWrite（DatabaseQueryMechanism.java:502） at org.eclipse.persistence.queries.InsertObjectQuery.executeCommit（InsertObjectQuery.java:80）在org.eclipse.persistence.queries.InsertObjectQuery.executeCommitWithChangeSet（InsertObjectQuery.java:90）在org.eclipse.persistence.internal.queries.DatabaseQueryMechanism.executeWriteWithChangeSet（DatabaseQueryMechanism.java:314） at org.eclipse.persistence.queries.WriteObjectQuery.executeDatabaseQuery（WriteObjectQuery.java:58）在org.eclipse.persistence.queries.DatabaseQuery.execute（DatabaseQuery.java:911） at org.eclipse.persistence.queries.DatabaseQuery.executeInUnitOfWork（DatabaseQuery.java:810） at org.eclipse.persistence.queries.ObjectLevelModifyQuery.executeInUnitOfWorkObjectLevelModifyQuery（ObjectLevelModifyQuery.java:108） at org.eclipse.persistence.queries.ObjectLevelModifyQuery.executeInUnitOfWork（ObjectLevelModifyQuery.java:85） at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery（UnitOfWorkImpl.java:2979） at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery（AbstractSession.java:1892） at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery（AbstractSession.java:1874） at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery（AbstractSession.java:1824） at org.eclipse.persistence.internal.sessions.CommitManager.commitNewObjectsForClassWithChangeSet（CommitManager.java:227） at org.eclipse.persistence.internal.sessions.CommitManager.commitAllObjectsForClassWithChangeSet（CommitManager.java:194）在org.eclipse.persistence.internal.sessions.CommitManager.commitAllObjectsWithChangeSet（CommitManager.java:139） at org.eclipse.persistence.internal.sessions.AbstractSession.writeAllObjectsWithChangeSet（AbstractSession.java:4384） at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabase（UnitOfWorkImpl.java:1491） at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabaseWithChangeSet（UnitOfWorkImpl.java:1581） at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.commitRootUnitOfWork（RepeatableWriteUnitOfWork.java:278） at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitAndResume（UnitOfWorkImpl.java:1218） at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commit（EntityTransactionImpl.java:134）在model.db.types.MovieDatabaseJpa.addMovie（MovieDatabaseJpa.java:66）在model.MovieService.addMovie（MovieService.java:19）在web.controller.MovieController.saveMovie（MovieController.java:72） at sun.reflect.NativeMethodAccessorImpl.invoke0（Native Method） at sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:62） at sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43） at java.lang.reflect.Method.invoke（Method.java:498）在org.springframework.web.method.support.InvocableHandlerMethod.doInvoke（InvocableHandlerMethod.java:209）在org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest（InvocableHandlerMethod.java:136）在org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle（ServletInvocableHandlerMethod.java:102）在org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod（RequestMappingHandlerAdapter.java:870）在org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal（RequestMappingHandlerAdapter.java:776）在org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle（AbstractHandlerMethodAdapter.java:87）在org.springframework.web.servlet.DispatcherServlet.doDispatch（DispatcherServlet.java:991）在org.springframework.web.servlet.DispatcherServlet.doService（DispatcherServlet.java:925）在org.springframework.web.servlet.FrameworkServlet.processRequest（FrameworkServlet.java:978）在org.springframework.web.servlet.FrameworkServlet.doPost（FrameworkServlet.java:881）

有人能指出我正确的方向吗？谢谢！

Answer 1

我解决了这个问题：

我使用了merge而不是persist，因为如果实体存在，它将更新它，否则插入它。

JPA ManyToMany重复键问题

1 个答案: