mysqldiff对数据库间进行差异比较
mysqldiff该工具是官方mysql-utilities工具集的一个脚本,可以用来对比不同数据库之间的表结构,或者同个数据库间的表结构
如果在windows下,直接下载mysql-utilities安装就可以了,然后运行后,会跑到命令行下:
1) 基本用法
mysqldiff --server1=admin:123456@192.168.79.10 --server2=admin:123456@192.168.79.11
--difftype=differ test:test
这样就比较两个不同库中的数据库test,假设两个库中库名都是test
也可以比较不同的表
mysqldiff --server1=user@host1 --server2=user@host2 testdb.table1:anotherdb.anothertable
就是使用库名.表名的方式就可以了
下面是出来的一个效果
# mysqldiff --force --server1=root:msandbox@127.0.0.1:21489 --server2=root:msandbox@127.0.0.1:21490 employees:employees
# WARNING: Using a password on the command line interface can be insecure.
# server1 on 127.0.0.1: ... connected.
# server2 on 127.0.0.1: ... connected.
# Comparing `employees` to `employees` [PASS]
# Comparing `employees`.`departments` to `employees`.`departments` [FAIL]
# Object definitions differ. (--changes-for=server1)
#
--- `employees`.`departments`
+++ `employees`.`departments`
@@ -1,6 +1,6 @@
CREATE TABLE `departments` (
`dept_no` char(4) NOT NULL,
- `dept_name` varchar(40) NOT NULL,
+ `dept_name` varchar(256) DEFAULT NULL,
PRIMARY KEY (`dept_no`),
UNIQUE KEY `dept_name` (`dept_name`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
可以看到,默认-号代表左边要比较的server1的变化,+号代表右边server2的不同,
如果要交换,可以使用参数:
–changes-for=server2
如果要在比较不同的时候,强行继续比较下去,要增加--force选项
2) 可以生成差异化的SQL,因为方法1)中,只产生了不同的地方,但如为了生产考虑,
要生成达到server2的脚本,则可以使用参数
--difftype=sql,
则:
mysqldiff --server1=admin:123456@192.168.79.10 --server2=admin:123456@192.168.79.11
--difftype=sql test:test
mysqldiff的核心是使用INFORMATION_SCHEMA
Java代码
- SHOW CREATE TABLE `departments`;
- SELECT TABLE_SCHEMA, TABLE_NAME, ENGINE, AUTO_INCREMENT, AVG_ROW_LENGTH, CHECKSUM, TABLE_COLLATION, TABLE_COMMENT, ROW_FORMAT, CREATE_OPTIONS
- FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'employees' AND TABLE_NAME = 'departments';
- SELECT ORDINAL_POSITION, COLUMN_NAME, COLUMN_TYPE, IS_NULLABLE,
- COLUMN_DEFAULT, EXTRA, COLUMN_COMMENT, COLUMN_KEY
- FROM INFORMATION_SCHEMA.COLUMNS
- WHERE TABLE_SCHEMA = 'employees' AND TABLE_NAME = 'departments';
- SELECT PARTITION_NAME, SUBPARTITION_NAME, PARTITION_ORDINAL_POSITION,
- SUBPARTITION_ORDINAL_POSITION, PARTITION_METHOD, SUBPARTITION_METHOD,
- PARTITION_EXPRESSION, SUBPARTITION_EXPRESSION, PARTITION_DESCRIPTION
- FROM INFORMATION_SCHEMA.PARTITIONS
- WHERE TABLE_SCHEMA = 'employees' AND TABLE_NAME = 'departments';
- SELECT CONSTRAINT_NAME, COLUMN_NAME, REFERENCED_TABLE_SCHEMA,
- REFERENCED_TABLE_NAME, REFERENCED_COLUMN_NAME
- FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE
- WHERE TABLE_SCHEMA = 'employees' AND TABLE_NAME = 'departments' AND
- REFERENCED_TABLE_SCHEMA IS NOT NULL;
- SELECT TABLE_SCHEMA, TABLE_NAME, ENGINE, AUTO_INCREMENT, AVG_ROW_LENGTH, CHECKSUM, TABLE_COLLATION, TABLE_COMMENT, ROW_FORMAT, CREATE_OPTIONS
- FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'employees' AND TABLE_NAME = 'departments';
- SELECT ORDINAL_POSITION, COLUMN_NAME, COLUMN_TYPE, IS_NULLABLE,
- COLUMN_DEFAULT, EXTRA, COLUMN_COMMENT, COLUMN_KEY
- FROM INFORMATION_SCHEMA.COLUMNS
- WHERE TABLE_SCHEMA = 'employees' AND TABLE_NAME = 'departments';
- SELECT PARTITION_NAME, SUBPARTITION_NAME, PARTITION_ORDINAL_POSITION,
- SUBPARTITION_ORDINAL_POSITION, PARTITION_METHOD, SUBPARTITION_METHOD,
- PARTITION_EXPRESSION, SUBPARTITION_EXPRESSION, PARTITION_DESCRIPTION
- FROM INFORMATION_SCHEMA.PARTITIONS
- WHERE TABLE_SCHEMA = 'employees' AND TABLE_NAME = 'departments';