数据库的基本创建

#创建数据库company
CREATE DATABASE company;
#创建表
USE company;
#创建表offices
CREATE TABLE offices
(
 officeCode INT(10) NOT NULL UNIQUE,
 city VARCHAR(50) NOT NULL,
 address VARCHAR(50) NOT NULL,
 country VARCHAR(50) NOT NULL,
 postalCode VARCHAR(15) NOT NULL,
 PRIMARY KEY(officeCode)
);
SHOW TABLES;
#创建表employees
CREATE TABLE employees
(
 employeeNumber INT(11) NOT NULL PRIMARY KEY AUTO_INCREMENT,
 lastName VARCHAR(50) NOT NULL,
 fristName VARCHAR(50) NOT NULL,
 mobile VARCHAR(25) NOT NULL,
 officeCode INT(10) NOT NULL,
 jobTitle VARCHAR(50) NOT NULL,
 birth DATETIME,
 note VARCHAR(255),
 sex VARCHAR(5),
 CONSTRAINT office_fk FOREIGN KEY(officeCode) REFERENCES offices(officeCode)
);
SHOW TABLES;
DESC offices;
ALTER TABLE  employees MODIFY mobile VARCHAR(25) AFTER of_ficeCode;
DESC employees;
ALTER TABLE  employees CHANGE birth employee_birth DATE-TIME;
DESC employees;
ALTER TABLE  employees MODIFY sex CHAR(1) NOT NULL;
DESC employees;
ALTER TABLE employees DROP note;
DESC employees;
ALTER TABLE employees ADD favoriate_activity VARCHAR(100);
DESC employees;
ALTER TABLE employees DROP FOREIGN KEY office_fk;
DESC employees;
DROP TABLE offices;
SHOW TABLES;
ALTER TABLE employees ENGINE=MYISAM;
DESC employees;
SHOW CREATE TABLE emplyees\G;
ALTER TABLE employees RENAME employees_info;
SHOW TABLES;