String hostUrl= "127.0.0.1";//Setup the connection with the DBClass.forName("com.mysql.jdbc.Driver"); Connection conn= DriverManager.getConnection("jdbc:mysql://" +hostUrl+ ":" +mySQLPort, userName, password);//--- LISTING DATABASE SCHEMA NAMES ---ResultSet resultSet =conn.getMetaData(...
方法3:查看information_schema.columns系统表 select table_schema,table_name,column_name,column_comment from information_schema.columns where table_schema='kerry' and table_name='employee' order by ordinal_position; 扫描上面二维码关注我 如果你真心觉得文章写得不错,而且对你有所帮助,那就不妨帮忙“推荐...
MySQL [(none)]> //因为没有配置权限所以查看的东西有限,看不到xudada的数据库 MySQL [(none)]> show databases; +---+ | Database | +---+ | information_schema | +---+ 1 row in set (0.01 sec) //删除数据库用户 //语法:DROP USER 'username'@'host'; mysql> drop user xuda@192.168....
复制 -- 使用合适的数据类型ALTERTABLEtable_nameMODIFYcolumn1INT;-- 分区表CREATETABLEtable_name(idINT,dataVARCHAR(100),createdDATE)PARTITIONBYRANGE(YEAR(created))(PARTITIONp0VALUESLESS THAN(1990),PARTITIONp1VALUESLESS THAN(2000),PARTITIONp2VALUESLESS THAN(2010),PARTITIONp3VALUESLESS THAN MAXVALUE); 5...
COLUMN_NAME AS '列名称', COLUMN_TYPE AS '数据类型', DATA_TYPE AS '字段类型', CHARACTER_MAXIMUM_LENGTH AS "长度", IS_NULLABLE AS '是否为空', COLUMN_DEFAULT AS '默认值', COLUMN_COMMENT AS '注释' FROM information_schema.COLUMNS
1. DDL 数据定义语言(Data Definition Language, DDL)是一组用于创建、修改和删除数据库对象的SQL语句。这些对象包括数据库本身(schema...
NULL for unique and primary-key constraints. For foreign-key constraints, this column is the ordinal position in key of the table that is being referenced. REFERENCED_TABLE_SCHEMA The name of the schema (database) referenced by the constraint. REFERENCED_TABLE_NAME The name of ...
Schema Name:pacific Table Name:employees Column Names: empNum – Holds integer values for the employee number. lastName – Holds varchar values for the last name of the employee. firstName – Holds varchar values for the first name of the employee. ...
INFORMATION_SCHEMA 修复了 “PROCESSLIST” 表中的一个性能问题。 安装 从MySQL 5.7 升级到更高版本的 MySQL 系列时,系统创建的 “mysql.sys” 和“mysql.session” 账户现在将修改为使用 “caching_sha2_password” 身份验证插件,而不是 “mysql_native_password” 插件。
TheCOLUMN_STATISTICStable has these columns: SCHEMA_NAME The names of the schema for which the statistics apply. TABLE_NAME The names of the column for which the statistics apply. COLUMN_NAME The names of the column for which the statistics apply. ...