我有这样一个 Hibernate 服务方法:"SELECT sc FROM SecurityContact sc WHERE sc.securityId=:securityId2"。 securityId2 由用户传入。每个 SecurityContact 都与一个 Contact 具有多对一的关系，因此 Hibernate 会在该查询运行时自动调用连接。但是，Hibernate 始终运行的连接是一个内部连接，对于我的目的来说它不能正常工作。有什么办法可以强制 Hibernate 在内部生成左外连接吗？下面是 SecurityContact 类的代码:

/**
 * The persistent class for the SecurityContact database table.
 * 
 */
@Entity
@FXClass(kind=FXClassKind.REMOTE)
public class SecurityContact implements Serializable {
    private static final long serialVersionUID = 1L;
    @Transient private String uid;
    @FXIgnore
    public String getUid() {
        if (uid == null) {
            uid = "" + securityContactId;
        }
        return uid;
    }

    public void setUid(String uid) {
        this.uid = uid;
    }

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(name="securityContact_id")
    private Long securityContactId;

    @Column(name="security_id")
    private String securityId;

    @Column(name="create_date")
    private String createDate;

    @Column(name="create_user")
    private String createUser;

    @Column(name="modify_date")
    private String modifyDate;

    @Column(name="modify_user")
    private String modifyUser;

    //bi-directional many-to-one association to AgentContact

    @ManyToOne
    @JoinColumn(name="agent_id", referencedColumnName="contact_id")
    private AgentContact agentContact;

    //bi-directional many-to-one association to AuditContact
    @ManyToOne
    @JoinColumn(name="audit_id", referencedColumnName="contact_id")
    private AgentContact auditContact;

    public SecurityContact() {
    }
    @FXKeyColumn
    public Long getSecurityContactId() {
        return this.securityContactId;
    }

    public void setSecurityContactId(Long securityContactId) {
        this.securityContactId = securityContactId;
    }

    public String getSecurityId() {
        return this.securityId;
    }

    public void setSecurityId(String securityId) {
        this.securityId = securityId;
    }

    public String getCreateDate() {
        return this.createDate;
    }

    public void setCreateDate(String createDate) {
        this.createDate = createDate;
    }

    public String getCreateUser() {
        return this.createUser;
    }

    public void setCreateUser(String createUser) {
        this.createUser = createUser;
    }

    public String getModifyDate() {
        return this.modifyDate;
    }

    public void setModifyDate(String modifyDate) {
        this.modifyDate = modifyDate;
    }

    public String getModifyUser() {
        return this.modifyUser;
    }

    public void setModifyUser(String modifyUser) {
        this.modifyUser = modifyUser;
    }
    @FXManyToOne(parent="parent", property="contactId")
    public AgentContact getAgentContact() {
        return this.agentContact;
    }

    public void setAgentContact(AgentContact agentContact) {
        this.agentContact = agentContact;
    }
    @FXManyToOne(parent="parent", property="contactId")
    public AgentContact getAuditContact() {
        return this.auditContact;
    }

    public void setAuditContact(AgentContact auditContact) {
        this.auditContact = auditContact;
    }

} 

最佳答案

在多对一匹配上尝试fetch=select

另见 http://community.jboss.org/wiki/AShortPrimerOnFetchingStrategies和 http://docs.jboss.org/hibernate/core/3.3/reference/en/html/mapping.html

关于java - Hibernate 左外连接，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/6904573/