Tables

A Database is a bunch of tables thats whre data is stored.

Create Table

--형식--
CREATE TABLE tablename
  (
    column_name data_type,
    column_name data_type
  );
-------

--EX--
create table cats(
	name varchar(100),
	age int
)

How to check it works? (Create Table)

1. SHOW TABLES

   mysql> show tables;
   +-------------------+
   | Tables_in_cat_app |
   +-------------------+
   | cats              |
   +-------------------+
   1 row in set (0.00 sec)

   It tells us that there is a cat table but that's pretty much it doesn't say anything about the contents of that table what are the different columns init.

2. SHOW COLUMS FROM <TABLE NAME>

   mysql> show columns from cats;
   +-------+--------------+------+-----+---------+-------+
   | Field | Type         | Null | Key | Default | Extra |
   +-------+--------------+------+-----+---------+-------+
   | name  | varchar(100) | YES  |     | NULL    |       |
   | age   | int          | YES  |     | NULL    |       |
   +-------+--------------+------+-----+---------+-------+
   2 rows in set (0.00 sec)

   or, use DESCRIBE <TABLE NAME>, DESC <TABLE NAME>

   mysql> describe cats;
   +-------+--------------+------+-----+---------+-------+
   | Field | Type         | Null | Key | Default | Extra |
   +-------+--------------+------+-----+---------+-------+
   | name  | varchar(100) | YES  |     | NULL    |       |
   | age   | int          | YES  |     | NULL    |       |
   +-------+--------------+------+-----+---------+-------+
   2 rows in set (0.00 sec)
   
   mysql> desc cats;
   +-------+--------------+------+-----+---------+-------+
   | Field | Type         | Null | Key | Default | Extra |
   +-------+--------------+------+-----+---------+-------+
   | name  | varchar(100) | YES  |     | NULL    |       |
   | age   | int          | YES  |     | NULL    |       |
   +-------+--------------+------+-----+---------+-------+
   2 rows in set (0.00 sec)

   차이점은 없다.