下载相关安装包 preinstall rpm 包 下载链接:https://yum.oracle.com/repo/OracleLinux/OL7/latest/x86_64/getPackage/oracle-database-preinstall-19c-1.0-1.e...
Continue reading数据库事务的隔离级别有4种,由低到高分别为Read uncommitted 、Read committed 、Repeatable read 、Serializable 。而且,在事务的并发操作中可能会出现脏读,不可重复读,幻读。下面通过事例一一阐述它们的概念与联系。 R...
Continue reading报错信息: Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was 20,8...
Continue readingSQL语言共分为四大类:数据查询语言DQL,数据操纵语言DML,数据定义语言DDL,数据控制语言DCL。 1. 数据查询语言DQL 数据查询语言DQL基本结构是由SELECT子句,FROM子句,WHERE子句组成的查询块: SELECT <字段名表> FROM ...
Continue readingAuthentication with old (insecure) passwords is not supported. For more information, lookup Password Hashing in the latest MySQL manual ...
Continue reading1.修改MySQL的登录设置: vi /etc/my.cnf 在[mysqld]的段中加上一句:skip-grant-tables 保存并且退出vi 2.重新启动mysqld /etc/init.d/mysqld restart 3.登录并修改MySQL的root密码 /...
Continue readingHSQLDB driverClassName=org.hsqldb.jdbcDriver url=jdbc:hsqldb:hsql://localhost:9001/bookstore MySQL 5 driverClassName=com.mysql.jdbc.Drive...
Continue readingORA-01861: 文字与格式字符串不匹配 可能是插入字符串没加引号,或插入时间直接按字符串插入,使用to_date函数转换一下就可以了,例如:to_date('2003-01-02','yyyy-mm-dd') ORA-00911: 无效字符 存在中文标点,或把字符串当...
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