使用构造函数表达式和JPQL使用DTO投影获取列表 [英] Fetch List Using DTO projections using a Constructor Expression and JPQL
问题描述
在DisabScreenRequest上执行搜索,并同时获取其子级详细信息.使用构造函数表达式和JPQL使用DTO投影.
Perform a search on DisabScreenRequest and fetch its child details also. Using DTO projections using a Constructor Expression and JPQL.
带有子表的父实体.
@Entity
@Table(name = "SCREEN_REQUEST")
public class DisabScreenRequest implements Serializable {
private static final long serialVersionUID = 1L;
@Id
private long requestId;
@Column(name = "CIVILID")
private Long civilId;
@ManyToMany()
@JoinTable(name = "_DISAB_SCREEN_REQ_DETAILS", joinColumns = {
@JoinColumn(name = "REQUEST_ID") }, inverseJoinColumns = { @JoinColumn(name = "DISABILTY_TYPE_ID") })
private Set<DisabMaster> disabilities = new HashSet<DisabMaster>();
public DisabScreenRequest() {
}
}
这是残疾表.
@Entity
@Table(name="DISAB_MASTER")
@Immutable
public class DisabMaster implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@Column(name="DIS_TYPE_ID")
private long disabilityTypeId;
@Column(name="DIS_TYPE_DESC")
private String disTypeDesc;
public DisabMaster() {
super();
}
}
必须提取所有请求以及每个请求的残障状态.
Had to fetch all the requests along with the disability for each request.
搜索DTO(使用此方法,除了这里提到的一个以外,我还有其他联接可以添加.
Search DTO(using this I had other joins to add other than one mentioned here).
public class RequestSearchDto {
private long requestId;
private Long civilId;
private Set<DisabMaster> disabilities;
public RequestSearchDto() {
super();
}
public RequestSearchDto(long requestId, Long civilId) {
super();
this.requestId = requestId;
this.civilId = civilId;
}
public RequestSearchDto(long requestId, Long civilId, Set<DisabMaster> disabilities) {
super();
this.requestId = requestId;
this.civilId = civilId;
this.disabilities = disabilities;
}
}
这是我的JPQL查询
public interface ReposJPQL {
public String GET__REQUEST = "SELECT DISTINCT new org.test.RequestSearchDto "
+ "(dsr.requestId, dsr.civilId, dsr.disabilities)"
+ " FROM DisabScreenRequest dsr WHERE 1=1 ";
}
这将得到一个 org.hibernate.exception.SQLGrammarException:无法提取ResultSet.
我在这里做错了什么,如何获取子表数据? 让我知道您是否需要任何信息
What Iam I doing wrong here, how can I fetch the child table data ? Let me know if you need any info
堆栈跟踪:
Caused by: java.sql.SQLException: ORA-00936: missing expression
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.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeQuery(NewProxyPreparedStatement.java:76)
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:60)
推荐答案
如果您需要使用其嵌套子实体的集合来获取父实体,则可以通过@EntityGraph
批注或JPQL和join fetch
使用此简单方法:
If you need to fetch parent entity with a collection of its nested child entities you can use this simple approach using @EntityGraph
annotation or JPQL with join fetch
:
@Entity
public class Parent {
//...
@OneToMany
private List<Child> children;
}
@Entity
public class Child {
//...
}
interface ParentRepo extends JpaRepository<Parent, Integer> {
// with @EntityGraph
@EntityGraph(attributePaths = "children")
@Override
List<Parent> findAll();
// or manually
@Query("select distinct p from Parent p left join fetch p.children")
List<Parent> findWithQuery();
}
请注意在查询中使用distinct
以避免重复记录.
Note to use distinct
in your query to avoid duplicate records.
示例:重复的父母实体
更多信息: DATAJPA-1299
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