Create a table, create a database, delete a table, delete a database

Create a table, create a database, delete a table, delete a database

1. Create a database

Create DATABASE Text2 Text2

2. Deleting a database

Drop database Text2 Delete the databases Text2

1. Create a table

The CREATE table class creates a form called class, which is a primary table.

(

Code varchar (primary key), creating the serial number

Name varchar () Not NULL creates a name that is not nullable

)

CREATE TABLE Ceshi creates a list called Ceshi this is from the table

(

IDS int Auto_increment Primary key, complete with commas for each sentence

UID varchar (20),

Name varchar (20),

Foreign key (Class) references class (code) to establish a foreign key relationship

)

*auto_increment Self-growth

*primary Key Primary Key

*foreign key (column name) references Main Table name (column name)

*not NULL non-null

Attention:

1. The type contains the length of the parentheses after the type, and the parentheses write the length
2. Add a comma when you finish writing the previous column
3. Don't write a comma in the last column
4. Be sure to add a semicolon after each SQL statement
5. Write the program code when you write in the English state
6. If you have a foreign key relationship, you must first create the main table * or it will go wrong!

1. Delete a table

DROP table class cannot delete a primary table with a foreign key relationship can be deleted from the table

Create a table, create a database, delete a table, delete a database