MySQL Create tables and databases

1. Create a Database: Code created: CREATE DATABASE: Database table name: Whatever you want, just remember it. Test

Create DATABASE test;

2. Delete database: Deleted code: Drop DATABASE code: database to delete which database: DB name: Test

drop database test;

3. Create a table: After the database is built, the table is created; example: CREATE TABLE code: Table name: Pick Ceshi

CREATE TABLE Class (    code varchar PRIMARY KEY,    name varchar () not null); CREATE TABLE Ceshi (    IDs int auto_ Increment primary KEY, uid varchar (+), name varchar (+),    class varchar,    foreign key (class)  References Class (code));

Note: Self-growth Code rep: auto_increment

The main building code represents: Primary Key

The code for the foreign key represents the formula: foreign key (column name) references Main Table name (column name)

Fornign key+ (column name) represents the column to which the add foreign key references to reference the table

Blank: Not empty code: NOT NULL

4. Delete: Delete code representative: Drop Delete is table: table to delete the name: Ceshi

drop table Ceshi;

Code write CREATE DATABASE is note:

1. The type contains the length, after the type plus (parentheses), the parentheses write the length

2. Complete the previous column with a comma

3. The last column do not write a comma

4. Add a semicolon after each SQL statement is finished;

5. If there is a foreign key relationship, first create the primary table

Example:

Creating Tables: Create Table Class (    code varchar PRIMARY key, name varchar), CREATE TABLE    student (    code varchar ( Primary key,    name varchar,    sex bit, age    int,    class varchar,    foreign key (class) References Class (code)), CREATE table Kecheng (    code varchar () primary key,    name varchar); CREATE TABLE Teacher (    Code varchar () primary key,    name varchar); CREATE TABLE Chengji (        IDs int auto_increment Primary key,    scode varchar,    kcode varchar,    degree float,    foreign key (SCODE) references Student (code),    foreign Key (Kcode) references Kecheng (code)); CREATE table Tkecheng (    IDs int auto_increment Primary key,    tcode varchar,    kcode varchar,    foreign KEY (Kcode) references Kecheng (code),    Foreign KEY (Tcode) references teacher (code));

MySQL Create tables and databases