问题:同样的代码,只能插入一组值,第二组值插入不了 解决:开始我将app_id作为主键,但很明显,同一个app_id会有不同的index,而同一个index也可能对应不同的app_id,因此只能添加一个id作为主键.开始只是将id作为主键,但这样需要每次将id添加进去,这是不现实的,因为不会每次都知道id到多少了:因此给了id一个默认值,这样也不现实,因为当组添加时id会相同,而id作为主键应该每次都不同, 所以最后将id选择AI(Auto Increment),自动增长,解决问题.…

MySQL完整性约束破坏异常:com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException 在单向多对一关联关系中,如果A 持有 B 的引用(即A是多端,B是一端),也就是A 的外键列指向了B 的主键.那么此时如果先删除B, 再删除A(即先删除一端,再删除A端).那么就会抛出上述异常. Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConst…

使用mybatis进行批量更新操作: 报错如下: 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 'update goods g SET update_date…

### Error querying database. Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Column 'org_mer_id' in where clause is ambiguous ### The error may exist in class path resource [mapper/StatisticsPeriodTaskMapper.xml] ##…

### Error updating database. Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry 'qingmu' for key 'PRIMARY' ### The error may involve com.qingmu2.core.dao.seller.SellerDao.insertSelective-Inline ### The…

java项目连接jdbc报错:com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server 原因:相关jar包版本太低 解决方法:下载最新版的mysql-connector-java即可…

严重: Servlet.service() for servlet jsp threw exceptioncom.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '88888888' for key 'PRIMARY'    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) …

严重: Servlet.service() for servlet [spring-mvc] in context with path [/learn] threw exception [Request processing failed; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement] with root causecom.mysql.j…

先瞧下日志: ### Error querying database. Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Expression #2 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'test.wlf_appinfo.appname' which is not functionally depend…

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection, message from server: "Too many connections" 原因:因为你的MySQL安装目录下的my.ini中设定的并发连接数太少或者系统繁忙导致连接数被占满 解决方式: 打开MYSQL安装目录打开MY.INI找到max_…