我对使用jpa还比较陌生,我有一个person实体类,我想在其中显示一些信息,首先当我创建这个类时,我将id设置为
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
它生成了一个51的id,我的老师告诉我把它改成:
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
所以从1开始,然后每个人加起来。
现在我有了一个结构java类,我想为运行该类的每个新示例删除当前数据库,我有以下代码:
public static void main(String[] args)
{
HashMap<String, Object> puProperties = new HashMap<>();
puProperties.put("javax.persistence.sql-load-script-source", "Scripts/ClearDB.sql");
Persistence.generateSchema("jpadb", puProperties);
puProperties.remove("javax.persistence.sql-load-script-source");
Persistence.generateSchema("jpadb", puProperties);
}
用这样的脚本:
drop database jpadb if exists;
create database jpadb;
下面是我得到的错误:
Internal Exception:
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an
error in your SQL syntax; check the manual that corresponds to your
MySQL server version for the right syntax to use near 'if exists' at line 1
Error Code: 1064
Call: drop database jpadb if exists;
Query: DataModifyQuery(sql="drop database jpadb if exists;")
[EL Warning]: 2018-09-11 16:14:41.361--ServerSession(2045766957)--
Exception [EclipseLink-4002] (Eclipse Persistence Services -
2.7.3.v20180807-4be1041):
org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: java.sql.SQLException: Can't create database
'jpadb'; database exists
Error Code: 1007
我不知道语法错误是指什么?
2条答案
按热度按时间smtd7mpg1#
将放弃声明更改为
错误信息很清楚你的陈述哪里是错的,
kq0g1dla2#
使用此脚本;
您的snytax错误已写入
drop database jpadb if exists;
. 你的问题其实是关键字的顺序。查看更多mysql drop文档