SQL → ER 图生成器

-- 班级表
    CREATE TABLE `t_class_info` (
        `class_id`    int(11) NOT NULL AUTO_INCREMENT COMMENT '班级ID',
        `class_name`  varchar(50) NOT NULL DEFAULT '' COMMENT '班级名称',
        `create_time` timestamp NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
        `update_time` timestamp NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新时间',
        PRIMARY KEY (`class_id`) USING BTREE
    ) ENGINE = InnoDB AUTO_INCREMENT = 1 COMMENT = '班级';
    
    -- 学生表存在外键约束
    CREATE TABLE `t_student` (
        `student_id`   int(11) NOT NULL AUTO_INCREMENT COMMENT '学生ID',
        `student_name` varchar(50) NOT NULL COMMENT '学生姓名',
        `birthdate`    timestamp NULL DEFAULT NULL,
        `class_id`     int(11) NULL DEFAULT NULL COMMENT '班级ID',
        `create_time`  timestamp NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
        `update_time`  timestamp NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新时间',
        PRIMARY KEY (`student_id`) USING BTREE,
        -- 添加外键约束
        CONSTRAINT `fk_student_class` FOREIGN KEY (`class_id`) REFERENCES `t_class_info` (`class_id`) ON DELETE SET NULL ON UPDATE CASCADE
    ) ENGINE = InnoDB AUTO_INCREMENT = 1 COMMENT = '学生';

ER 图预览