我将 JPA 2 与 Eclipselink 2 和内存数据库中的 Derby 一起用于我的测试。当我启动我的小测试程序时,出现以下异常:
[EL Warning]: 2010-08-12 17:17:44.943--ServerSession(948252856)--Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.0.2.v20100323-r6872): org.eclipse.persistence.exceptions.DatabaseException Internal Exception: java.sql.SQLSyntaxErrorException: 'ALTER TABLE' cannot be performed on 'ARTICLE_ARTICLE' because it does not exist. Error Code: 30000 Call: ALTER TABLE ARTICLE_ARTICLE DROP CONSTRAINT RTCLrtclsRltdTThsD Query: DataModifyQuery(sql="ALTER TABLE ARTICLE_ARTICLE DROP CONSTRAINT RTCLrtclsRltdTThsD")
如果我对 HyperSQL (hsqldb) 进行同样的尝试,我会得到:
[EL Warning]: 2010-08-12 17:47:33.179--ServerSession(1925661675)--Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.0.2.v20100323-r6872): org.eclipse.persistence.exceptions.DatabaseException Internal Exception: java.sql.SQLException: user lacks privilege or object not found: ARTICLE_ARTICLE Error Code: -5501 Call: ALTER TABLE ARTICLE_ARTICLE DROP CONSTRAINT FK_ARTICLE_ARTICLE_articlesRelatedToThis_ID Query: DataModifyQuery(sql="ALTER TABLE ARTICLE_ARTICLE DROP CONSTRAINT FK_ARTICLE_ARTICLE_articlesRelatedToThis_ID")
表的生成策略是“drop-and-create”,为什么Eclipselink会告诉我表不存在?
还是我的示例类有问题?
@Entity
public class Article implements Serializable {
@Id @GeneratedValue
private int id;
private String title;
@ManyToMany(mappedBy = "relatedArticles")
private Set<Article> articlesRelatedToThis = new HashSet<Article>();
@ManyToMany(cascade = CascadeType.PERSIST)
private Set<Article> relatedArticles = new HashSet<Article>();
public Article() {}
public Article(String title) {
this.title = title;
}
public int getId() {
return id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public Set<Article> getRelatedArticles() {
return relatedArticles;
}
public void addRelatedArticle(Article related) {
relatedArticles.add(related);
}
public void removeRelatedArticle(Article related) {
relatedArticles.remove(related);
}
@PreRemove
public void preRemove() {
for(Article article : articlesRelatedToThis)
article.removeRelatedArticle(this);
}
}
最佳答案
The table generation strategy is "drop-and-create", so why does Eclipselink tell me that a table would not exist?
EcliseLink 首先删除表约束(您看到的 alter 语句),然后是表,然后重新创建所有内容。由于您使用的是内存数据库,因此实际上没有什么可删除的,并且 EclipseLink 将失败尝试报告为警告。忽略它们。
关于java - 无法执行“ALTER TABLE”,因为表不存在,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/3469303/