Guruh talabasi Abdig’opporov javoxir Mysql 1-2-amaliy ishlar

Example
mysql> CREATE TABLE employees (
emp_no INT UNSIGNED NOT NULL AUTO_INCREMENT,
name VARCHAR(50) NOT NULL,
gender ENUM ('M','F') NOT NULL,
birth_date DATE NOT NULL,
hire_date DATE NOT NULL,
PRIMARY KEY (emp_no) -- Index built automatically on primary-key column
);
mysql> DESCRIBE employees;
+------------+------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------+------------------+------+-----+---------+----------------+
| emp_no | int(10) unsigned | NO | PRI | NULL | auto_increment |
| name | varchar(50) | NO | | NULL | |
| gender | enum('M','F') | NO | | NULL | |
| birth_date | date | NO | | NULL | |
| hire_date | date | NO | | NULL | |
+------------+------------------+------+-----+---------+----------------+
mysql> SHOW INDEX FROM employees \G
*************************** 1. row ***************************
Table: employees
Non_unique: 0
Key_name: PRIMARY
Seq_in_index: 1
Column_name: emp_no
.......

mysql> CREATE TABLE departments (

dept_no CHAR(4) NOT NULL,
dept_name VARCHAR(40) NOT NULL,
PRIMARY KEY (dept_no), -- Index built automatically on primary-key column
UNIQUE INDEX (dept_name) -- Build INDEX on this unique-value column
);
mysql> DESCRIBE departments;
+-----------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------+-------------+------+-----+---------+-------+
| dept_no | char(4) | NO | PRI | NULL | |
| dept_name | varchar(40) | NO | UNI | NULL | |
+-----------+-------------+------+-----+---------+-------+

mysql> SHOW INDEX FROM departments \G

*************************** 1. row ***************************
Table: departments
Non_unique: 0
Key_name: PRIMARY
Seq_in_index: 1
Column_name: dept_no
.......
*************************** 2. row ***************************
Table: departments
Non_unique: 0
Key_name: dept_name
Seq_in_index: 1
Column_name: dept_name
.......
-- Many-to-many junction table between employees and departments
mysql> CREATE TABLE dept_emp (