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建表 或 修改表 给某字段默认值

时间:2020-03-19 11:30:45      阅读:54      评论:0      收藏:0      [点我收藏+]

解决问题:根据厂家编号分类 没有填写的厂家编号默认为一组 称之为‘其他‘

建表给某字段 默认字符串

CREATE TABLE `t_device_list`  (
  `device_id` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT 终端ID,
  `device_manufacturer_id` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL DEFAULT ‘cs999999‘ COMMENT 终端厂商编号,
  `business_terminal` varchar(10) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT bt999999 COMMENT 业务终端(A:集中器,B:配变终端,C:二遥,D:三遥,E:其他),
  `network_port` varchar(255) CHARACTER SET utf16le COLLATE utf16le_general_ci NULL DEFAULT NULL COMMENT 网管端口,
  PRIMARY KEY (`device_id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci COMMENT = 终端设备基本信息  不会变化的信息存储于此表 ROW_FORMAT = Compact;

修改表 给某字段 默认字符串

alter table t_device_list alter column business_terminal set default bt999999;
alter table t_device_list alter column device_manufacturer_id set default cs999999;

建表给某字段 默认当前时间

CREATE TABLE `t_device_manufacturer`  (
  `id` int(20) NOT NULL AUTO_INCREMENT COMMENT 主键,
  `device_manufacturer_id` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT 厂家id,
  `device_manufacturer_name` varchar(30) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT 厂家名称,
  `create_time` datetime(0) NULL DEFAULT NULL COMMENT 创建时间,
  `update_time` datetime(0) NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP(0) COMMENT 更新时间,
  PRIMARY KEY (`id`) USING BTREE,
  INDEX `index_id_name`(`device_manufacturer_id`, `device_manufacturer_name`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 7 CHARACTER SET = utf8 COLLATE = utf8_general_ci COMMENT = 厂家表 ROW_FORMAT = Compact;

 

建表 或 修改表 给某字段默认值

原文:https://www.cnblogs.com/s6-b/p/12522656.html

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