当对象是另一个实体类的属性时，使用HQL选择对象列表

Question

我正在尝试使用HQL-

从以下Entity类中获取List<Role>

@Entity
@Table(name="APPL_APPROVAL_ROLES")

public class ApplApprovalRoles implements Serializable, Comparable<ApplApprovalRoles> {

    private static final long serialVersionUID = 1L;

    @Id
    @Column(name="id", updatable=false)
    @SequenceGenerator(name="appl_approval_roles_id_seq",sequenceName="appl_approval_roles_id_seq")
    @GeneratedValue(generator="appl_approval_roles_id_seq")
    private int id;

    @Column(name="appl_name")
    private String applName;

    @OneToOne
    @JoinColumn(name="client_id")
    private Client client;

    @OneToOne
    @JoinColumn(name="role_id")
    private Role role;

    @Column(name="stage_num")
    private int stageNum;

    @Column(name="active",length=1)
    @Type(type="yes_no")
    private boolean active = false;

    public ApplApprovalRoles(){}
    public ApplApprovalRoles(int stageNum, String applName, 
            Client client, Role role, boolean active){

        this.stageNum = stageNum;
        this.applName = applName;
        this.client = client;
        this.role = role;
        this.active = active;
    }

    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }

    public String getApplName() {
        return applName;
    }
    public void setApplName(String applName) {
        this.applName = applName;
    }

    public Client getClient() {
        return client;
    }
    public void setClient(Client client) {
        this.client = client;
    }

    public Role getRole() {
        return role;
    }
    public void setRole(Role role) {
        this.role = role;
    }

    public int getStageNum() {
        return stageNum;
    }
    public void setStageNum(int stageNum) {
        this.stageNum = stageNum;
    }

    public boolean isActive() {
        return active;
    }

    public void setActive(boolean active) {
        this.active = active;
    }
}

角色等级是 -

@Entity
@Table(name="role")
public class Role implements Serializable, Comparable<Role> {

    @Id
    @Column(name="id", updatable=false)
    @SequenceGenerator(name="role_id_seq", sequenceName="role_id_seq")
    @GeneratedValue(generator="role_id_seq")
    private int id;

    @OneToOne
    @JoinColumn(name="client_id", nullable=false)
    private Client client;

    @Column(name="code", nullable=true)
    private String code;

    @Column(name="name", nullable=false)
    private String name;

    @Column(name="binary_code")
    private String binaryCode;

    public Role(){}

    public Role(int id, String code, String name) {
        this.id = id;
        this.code = code;
        this.name = name;
    }

    public Role(String code, String name, Client client) {
        this.code = code;
        this.name = name;
        this.client = client;
    }

    public Role(Client client) {
        this.client = client;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id=id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public Client getClient() {
        return client;
    }

    public void setClient(Client client) {
        this.client = client;
    }
} 

我正在尝试的HQL -

@SuppressWarnings("unchecked")
public List<Role> getRoleByClientAndAppName(Client client, String applName){
    String hql = "select role from ApplApprovalRoles where client_id = :clientId and appl_name = :applName";
    Session session = this.getSessionFactory().getCurrentSession();
    Query query = session.createQuery(hql);
    query.setParameter("clientId", client.getId());
    query.setParameter("applName", applName);

    List<Role> roles = (List<Role>)query.list();

    return roles;
}

这给了我以下错误 -

javax.el.ELException: org.hibernate.exception.SQLGrammarException: could not execute query
    at org.jboss.el.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:332)
    at org.jboss.el.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:273)
    at org.jboss.el.parser.AstMethodSuffix.getValue(AstMethodSuffix.java:59)
    at org.jboss.el.parser.AstValue.getValue(AstValue.java:67)
    at org.jboss.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:186)
    at org.springframework.binding.expression.el.BindingValueExpression.getValue(BindingValueExpression.java:54)
    at org.springframework.binding.expression.el.ELExpression.getValue(ELExpression.java:54)
    ... 58 more
Caused by: org.hibernate.exception.SQLGrammarException: could not execute query
    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:90)
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
    at org.hibernate.loader.Loader.doList(Loader.java:2235)
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2129)
    at org.hibernate.loader.Loader.list(Loader.java:2124)
    at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:401)
    at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:363)
    at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196)
    at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1149)
    at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
    at 
    at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149)
    at org.springframework.aop.framework.Cglib2AopProxy$CglibMethodInvocation.invokeJoinpoint(Cglib2AopProxy.java:692)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:107)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:625)
    at com.infoimage.infotrac.proofing.service.ProofingLogService$$EnhancerByCGLIB$$d2fe9334.getRoleBasedProofingList(<generated>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.jboss.el.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:328)
    ... 64 more
Caused by: java.sql.SQLException: ORA-00918: column ambiguously defined

    at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:113)
    at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:331)
    at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:288)
    at oracle.jdbc.driver.T4C8Oall.receive(T4C8Oall.java:754)
    at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:219)
    at oracle.jdbc.driver.T4CPreparedStatement.executeForDescribe(T4CPreparedStatement.java:813)
    at oracle.jdbc.driver.OracleStatement.executeMaybeDescribe(OracleStatement.java:1051)
    at oracle.jdbc.driver.T4CPreparedStatement.executeMaybeDescribe(T4CPreparedStatement.java:854)
    at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1156)
    at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3415)
    at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:3460)
    at com.caucho.sql.UserPreparedStatement.executeQuery(UserPreparedStatement.java:108)
    at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:208)
    at org.hibernate.loader.Loader.getResultSet(Loader.java:1812)
    at org.hibernate.loader.Loader.doQuery(Loader.java:697)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
    at org.hibernate.loader.Loader.doList(Loader.java:2232)
    ... 86 more

用于选择所有角色的等效oracle SQL查询是 -

select ROLE_ID from APPL_APPROVAL_ROLES where CLIENT_ID='clnt110' and APPL_NAME='Checking_statements';

SQL工作正常。但是HQL出现了问题。谁能帮我？ 非常感谢。

Answer 1

Chaitanya感谢您的回答。当我尝试您的回答时，它会给出org.hibernate.hql.ast.QuerySyntaxException: Invalid path: 'client.id'错误。然后我使用下面的hql（只是你的hql的一点修改），它给了我正确的结果 -

String hql = "select role from ApplApprovalRoles a where a.client.id = :clientId and a.applName = :applName";

Answer 2

要创建HQL查询，您必须使用实体的实体和属性，因此将HQL查询更改为：

String hql = "select role from ApplApprovalRoles where client.id = :clientId and applName = :applName";

假设id是Client实体中代表标识符的属性。

Answer 3

String hql = "SELECT role FROM ApplApprovalRoles WHERE client.id = :clientId AND applName = :applName";