Question

在使用EclipseLink的JPA应用程序中，循环实体与Keyword实体具有oneToMany关系。循环实体有两个@Lob类型的属性。当我运行此JQL以获取不同的实体时，我收到以下错误。如何在具有@Lob属性的实体中使用distinct in？

JQL是

SQL is select DISTINCT c from CircularKeyword k join k.circular c where c.retired = false and c.administrativeDivision.id = 1  and k.retired = false and  ( upper(c.circularNumber) like '%3%' or  upper(c.topic) like '%3%' or  upper(k.name) like '%3%'   )  order by c.name

错误是

Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: java.sql.SQLException: Columns of type 'BLOB' may not be used in CREATE INDEX, ORDER BY, GROUP BY, UNION, INTERSECT, EXCEPT or DISTINCT statements because comparisons are not supported for that type.
Error Code: -1
Call: SELECT DISTINCT t0.ID, t0.BAIMAGE, t0.CIRCULARDATE, t0.CIRCULARLANGUAGE, t0.CIRCULARNUMBER, t0.CODE, t0.CONTENTS, t0.CREATEDAT, t0.DESCRIPTION, t0.FILENAME, t0.FILETYPE, t0.INTERNAL, t0.KEYWORDS, t0.NAME, t0.ORIGINATINGFILENO, t0.RETIRECOMMENTS, t0.RETIRED, t0.RETIREDAT, t0.TOPIC, t0.ADMINISTRATIVEDIVISION_ID, t0.CATEGORY_ID, t0.CREATER_ID, t0.PERSON_ID, t0.RETIRER_ID, t0.SIGNINGAUTHORITY_ID FROM CIRCULAR t0, CIRCULARKEYWORD t1 WHERE (((((t0.RETIRED = ?) AND (t0.ADMINISTRATIVEDIVISION_ID = ?)) AND (t1.RETIRED = ?)) AND ((UCASE(t0.CIRCULARNUMBER) LIKE ? OR UCASE(t0.TOPIC) LIKE ?) OR UCASE(t1.NAME) LIKE ?)) AND (t0.ID = t1.CIRCULAR_ID)) ORDER BY t0.NAME ASC
    bind => [6 parameters bound]
Query: ReportQuery(referenceClass=CircularKeyword sql="SELECT DISTINCT t0.ID, t0.BAIMAGE, t0.CIRCULARDATE, t0.CIRCULARLANGUAGE, t0.CIRCULARNUMBER, t0.CODE, t0.CONTENTS, t0.CREATEDAT, t0.DESCRIPTION, t0.FILENAME, t0.FILETYPE, t0.INTERNAL, t0.KEYWORDS, t0.NAME, t0.ORIGINATINGFILENO, t0.RETIRECOMMENTS, t0.RETIRED, t0.RETIREDAT, t0.TOPIC, t0.ADMINISTRATIVEDIVISION_ID, t0.CATEGORY_ID, t0.CREATER_ID, t0.PERSON_ID, t0.RETIRER_ID, t0.SIGNINGAUTHORITY_ID FROM CIRCULAR t0, CIRCULARKEYWORD t1 WHERE (((((t0.RETIRED = ?) AND (t0.ADMINISTRATIVEDIVISION_ID = ?)) AND (t1.RETIRED = ?)) AND ((UCASE(t0.CIRCULARNUMBER) LIKE ? OR UCASE(t0.TOPIC) LIKE ?) OR UCASE(t1.NAME) LIKE ?)) AND (t0.ID = t1.CIRCULAR_ID)) ORDER BY t0.NAME ASC")

Answer 1

假设circular有一个简单的ID，您可以通过更新查询以仅选择不同的标识符作为子查询来解决此问题：

SELECT k.circular FROM CircularKeyword k 
WHERE k.circular.id IN (SELECT DISTINCT c.id FROM CircularKeyword k2 
                        JOIN k2.circular c ...rest of your query...)

重要的是，您要求DISTINCT c.id而不是DISTINCT c，以便生成的本机SQL不会包含带有BLOB语句的DISTINCT列。< / p>

Answer 2

可以解决此问题的另一个选择是将@Lob包装到单独的实体中。这是有效的，因为它不会尝试解析实际的lob，而只会尝试解析数据库可以处理的lob键引用。我已经使用提供的信息对一个工作代码片段进行了调整。

循环实体

//Other attributes, and ids omitted

@ManyToOne()
@JoinColumn(name = "LOB_ATTRIBUTE_1_KEY")
LobAttribute lobAttribute1;

@ManyToOne()
@JoinColumn(name = "LOB_ATTRIBUTE_2_KEY")
LobAttribute lobAttribute2;

LobAttribute Entity

@Id
@Column(name = "LOB_ATTRIBUTE_KEY")
Long lobAttributeKey;

@Lob
@Basic(fetch = FetchType.LAZY)
@Column(name = "LOB")
String lob;

我不是特别喜欢这个，但我相信这是对查询和模型的限制最少的最佳解决方案。我希望这可以帮助遇到这个的任何人。

JQL与具有@Lob属性的实体不同

2 个答案: