Question

我正在使用mysql和ecliselink构建基于JPA的应用程序。当我尝试将东西插入我的数据库时，我有一个非常奇怪的问题。我能够将数据插入到单个表中但是当它涉及到一对一时，反之亦然出现问题。目前我有2个主表和1个引用表（它保存了另外两个表的外键）。这很奇怪，因为我的数据库表中没有“序列”当我尝试将数据插入到我的任何一个表中时表格我得到了这个例外：

[EL Info]: 2012-03-15 17:52:28.64--ServerSession(18621340)--EclipseLink, version: Eclipse Persistence Services - 2.3.2.v20111125-r10461 
[EL Info]: 2012-03-15 17:52:29.23--ServerSession(18621340)--file:/D:/git-eclipse/Martin/reference/build/classes/_reference login successful 
[EL Warning]: 2012-03-15 17:52:29.389--ClientSession(31843177)--Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.DatabaseException 
Internal Exception: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Table 'eclipse1.sequence' doesn't exist 
Error Code: 1146 
Call: UPDATE SEQUENCE SET SEQ_COUNT = SEQ_COUNT + ? WHERE SEQ_NAME = ? 
bind => [2 parameters bound] 
Query: DataModifyQuery(name="SEQUENCE" sql="UPDATE SEQUENCE SET SEQ_COUNT = SEQ_COUNT + ? WHERE SEQ_NAME = ?") 

Internal Exception: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Table 'eclipse1.sequence' doesn't exist 
Error Code: 1146 
Call: UPDATE SEQUENCE SET SEQ_COUNT = SEQ_COUNT + ? WHERE SEQ_NAME = ? 
bind => [2 parameters bound] 
Query: DataModifyQuery(name="SEQUENCE" sql="UPDATE SEQUENCE SET SEQ_COUNT = SEQ_COUNT + ? WHERE SEQ_NAME = ?") 
[EL Info]: 2012-03-15 17:52:29.394--ServerSession(18621340)--file:/D:/git-eclipse/Martin/reference/build/classes/_reference logout successful 
Exception in thread "main" java.lang.IllegalStateException: Attempting to execute an operation on a closed EntityManager. 
at org.eclipse.persistence.internal.jpa.EntityManagerImpl.verifyOpen(EntityManagerImpl.java:1665) 
at org.eclipse.persistence.internal.jpa.EntityManagerImpl.close(EntityManagerImpl.java:1529) 
at OneToManyRelation.main(OneToManyRelation.java:47)

我只发布一个类，因为其他类非常相似

@Entity

    @Table(name="category")

    public class Category {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(name="CategoryID")
    private int CategoryID;

/**
* @return the id
*/
public int getId() {
return CategoryID;
}

/**
* @param id the id to set
*/
public void setId(int CategoryID) {
this.CategoryID = CategoryID;
}

@Column(name="category", nullable=false, length=50, insertable=true)
private String category;

/**
* @return the category
*/
public String getCategory() {
return category;
}


public void setCategory(String category) {
this.category = category;
}

@OneToMany(cascade=CascadeType.ALL)
@JoinTable(name = "templateemail", joinColumns = {
@JoinColumn(name="categoryId", unique = true) 
},
inverseJoinColumns = {
@JoinColumn(name="templateId")
}
)
private Set<Template> template;

/**
* 
*/
public Set<Template> getChildren() {
return template;
}

/**
* 
*/
public void setChildren(Set<Template> template) {
this.template = template;
}

}

你知道我的代码有什么问题吗？

提前致谢

Answer 1

查看代码有助于找出问题所在。但是，通过仅判断错误消息，您似乎选择使用序列或表生成器，并且此生成器（默认情况下）依赖于名为sequence的表，该表在数据库中不存在。 / p>

创建此表，或将生成器配置为使用现有表，或更改ID生成器。

JPA / MySql问题

1 个答案: