如何检测 MySQL 数据库结构是否发生变化(不是内容)?
mysqlmysqli database
我们先看一个例子，创建一个表 −
mysql> create table DemoTable ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentName varchar(40), StudentAge int, StudentMarks int ); Query OK, 0 rows impacted (0.76 sec)
以下是了解数据库结构的查询 −
mysql> show create table DemoTable;
这将产生以下输出 −
+---------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Table | Create Table | +---------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | DemoTable | CREATE TABLE `DemoTable` (`StudentId` int(11) NOT NULL AUTO_INCREMENT, `StudentName` archar(40) COLLATE utf8_unicode_ci DEFAULT NULL, `StudentAge` int(11) DEFAULT NULL, `StudentMarks` int(11) DEFAULT NULL, PRIMARY KEY (`StudentId`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci | +---------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.06 sec)
现在，让我们更改数据库结构 −
mysql> alter table DemoTable add column StudentCountryName varchar(20); Query OK, 0 rows affected (0.65 sec) Records : 0 Duplicates : 0 Warnings : 0
现在我们将再次检查数据库结构 −
mysql> show create table DemoTable;
这将产生以下输出。我们现在可以匹配结构中的更改 −
+---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Table | Create Table | +---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | DemoTable | CREATE TABLE `DemoTable` ( `StudentId` int(11) NOT NULL AUTO_INCREMENT, `StudentName` varchar(40) COLLATE utf8_unicode_ci DEFAULT NULL, `StudentAge` int(11) DEFAULT NULL, `StudentMarks` int(11) DEFAULT NULL, `StudentCountryName` varchar(20) COLLATE utf8_unicode_ci DEFAULT NULL, PRIMARY KEY (`StudentId`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci | +---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec)
