1. There are two types of MySQL instructions (Data Definition Language) DDL: Create database, create table, alter table,,,. (Data Manipulation Language) DML Replace, delete, insert, update, select,,,.

2. Review show databases; create database New_database; use new_database; show tables; create table (column_name data_type [not null] …,)); describe ; INSERT INTO table_name SET col_name3=value3, …; SELECT col_name1 FROM table_name; SELECT * FROM table_name;

3. What are the current databases at the server? mysql> show databases; +--------------+ | Database | +--------------+ | mysql | mysql is a database (stores users’ password …) used by system. | test | +--------------+ Create a database (make a directory) whose name is MyDB mysql> create database MyDB; Select database to use mysql> use MyDB; Database changed What tables are currently stored in the MyDB database? mysql> show tables; Empty set (0.00 sec) Create Database

4. CREATE TABLE Table_Name (column_specifications) Example mysql> CREATE TABLE student -> ( -> student_ID INT UNSIGNED NOT NULL, -> name VARCHAR(20) NOT NULL, -> major VARCHAR(50), -> grade VARCHAR(5) -> ); Query OK, 0 rows affected (0.00 sec) Student_IDNameMajorGrade Create Table

5. mysql> show tables; +--------------------+ | Tables_in_MyDB | +--------------------+ | student | +--------------------+ 1 row in set (0.00 sec) mysql> describe student; +---------------+----------------------+------+------+----------+--------+ | Field | Type | Null | Key | Default | Extra | +---------------+----------------------+-------+-----+-----------+-------+ | student_ID | int(10) unsigned | | | 0 | | | name | varchar(20) | | | | | | major | varchar(50) | YES | | NULL | | | grade | varchar(5) | YES | | NULL | | +---------------+----------------------+-------+------+----------+-------+ 4 rows in set (0.00 sec) Display Table Structure

6. use mysql; show tables; describe db;

7. ALTER TABLE table_name Operations mysql> alter table student add primary key (student_ID); Query OK, 0 rows affected (0.00 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> describe student; +---------------+--------------------- +-------+------+----------+-------+ | Field | Type | Null | Key | Default | Extra | +---------------+----------------------+-------+------+----------+-------+ | student_ID | int(10) unsigned | | PRI | 0 | | | name | varchar(20) | | | | | | major | varchar(10) | YES | | NULL | | | grade | varchar(5) | YES | | NULL | | +---------------+----------------------+-------+------+-----------+-------+ 4 rows in set (0.00 sec) Modify Table Structure

8. Alter Alter table table_name Add column_name VARCHAR(20) NOT NULL; Alter table table_name Change column_name VARCHAR(20) NOT NULL;

9. Lab Exercise create database school; use school; create table students( s_name varchar(15) not null, s_numbers varchar(4) not null, s_teachers char(15) ); create table teachers( t_names varchar(15) not null, t_numbers varchar(4) not null, t_students varchar(15) not null); alter table students add primary key (s_numbers); alter table teachers add primary key (t_numbers); alter table students modify s_teachers varchar(4) not null; alter table students add foreign key(s_teachers) references teachers(t_numbers); alter table students change s_name s_names varchar(15) not null;

11. describe students; describe teachers;

12. alter table teachers drop t_students; describe teachers;

13. Alter with (add) operation When we write : create table students( s_name varchar(15) not null, s_numbers varchar(4) not null ); alter table students add primary key (s_numbers); It’s the same as we write : create table students( s_name varchar(15) not null, s_numbers varchar(4) not null, primary key (s_numbers) );

14. To add into the tables

15. select * from students; select * from teachers;

16. I want a table of students and their teachers

17. select s_names, s_numbers, t_names, t_numbers from students, teachers where s_teachers = t_numbers;

18. OK, now I want a table of Kmal students

19. select s_names, s_numbers from students where s_teachers = '21';

20. select s_names, s_numbers from students where s_teachers ='21' order by s_names;

21. References Dr. Hsiang-Fu Yu, National Taipei University of Education