Question

I get this error, when trying to connect two table via manytomany:
ERROR [org.hibernate.tool.hbm2ddl.SchemaUpdate] Unsuccessful: alter table PARAM_TRENDVALUE add constraint FK_TrendValue foreign key (AreaID, PcID, DeviceID, ValueID) references usrIFDBMaster.tblTrdProcessValues
08:44:43,800 ERROR [org.hibernate.tool.hbm2ddl.SchemaUpdate] Die ‘usrIFDBMaster.tblTrdProcessValues.DeviceID’-Spalte hat nicht denselben Datentyp wie die verweisende ‘PARAM_TRENDVALUE.PcID’-Spalte im ‘FK_TrendValue’-Fremdschlüssel.

Principaly hibernate is trying to map the wrong columns.

Param.java:

This is the key:

@EmbeddedId
@AttributeOverrides( {
        @AttributeOverride(name = "pcId", column = @Column(name = "PcID", nullable = false)),
        @AttributeOverride(name = "unitId", column = @Column(name = "UnitID", nullable = false)),
        @AttributeOverride(name = "paramId", column = @Column(name = "ParamID", nullable = false)) })
public ParamId getId() {
    return this.id;
}

This is the mapping:

/**
 * @return the connection
 */
@ManyToMany
@ForeignKey(name = "FK_Param")
@JoinTable(
        name="PARAM_TRENDVALUE",
        inverseJoinColumns={    
                @JoinColumn(name = "PcID", referencedColumnName = "PcID"),
                @JoinColumn(name = "AreaID", referencedColumnName = "AreaID"),
                @JoinColumn(name = "DeviceID", referencedColumnName = "DeviceID"),
                @JoinColumn(name = "ValueID", referencedColumnName = "ValueID")
        }
)
public List<TrendValue> getTrendValues() {
    return trendValues; 
}

Trendvalue.java:

This is the key:

@EmbeddedId
@AttributeOverrides( {
        @AttributeOverride(name = "pcId", column = @Column(name = "PcID", nullable = false)),   
        @AttributeOverride(name = "areaId", column = @Column(name = "AreaID", nullable = false)),
        @AttributeOverride(name = "deviceId", column = @Column(name = "DeviceID", nullable = false)),
        @AttributeOverride(name = "valueId", column = @Column(name = "ValueID", nullable = false))
         })
public TrendValueId getId() {
    return this.id;
}

This is the mapping:

/**
 * @return the params
 */
@ManyToMany(
        mappedBy="trendValues",
        targetEntity=Param.class
    )
@ForeignKey(name = "FK_TrendValue")
public List<Param> getParams() {
    return params;
}

It´s the first manytomany I try to use, and it should work, I already tried without inversejoincolumns, with joincolumns, defining exactly the tables and datatypes in “joincolumns/inversejoincolumns”, …
Don’t know what else could be the problem.

Answer 1

This is not the way it should work, but it worked: I added the connection table manually, both the foreign keys too, but, as shown in the picture I had too keep this exact order of the keys! Thats not the order as it is shown in the main table TrendValues, but it seems to be some random order…

If somebody knows, why this order has to be this way, and how I can change hibernate annotations, so that it takes this same order, I’d be very grateful.

Also, I can now start the program, with the my annotations but the tables aren’t changed anymore.