MySQL Command Collation 1

1. Database Login operation:
Database Login

- - - -P

Local login:

Mysql-u root-p

2. Database Management operations:
View all databases:

show databases;

Create a new database and set the database encoding to UTF8:

Create database db character set UTF8;

Modify the database encoding to UTF8:

Alter database db charset=UTF8;

To display the CREATE database information:

Create database db;

To delete a database:

Drop database db;

Drop Database if exists db;

3. Data Sheet Management operations
View Data Sheet:

Show tables;

To create a table:

Create Table int Char (int);

To display the CREATE table information:

Create  table name;

Add Field:

Alter Table Add Char (4);

To delete a field:

Alter Table drop field name;

To modify the data type of a field:

Alter Table varchar (a);

Modify the data type of the field and change the field name:

Alter Table  Number smallint;

To delete a data table:

Drop Table if exists Stu;

4. Data management operations:
Data query:

Select *  from Stu;

Insert data:
A. Inserting all fields

Insert  into Stu value (1'Tom');

B. Inserting a specified field

Insert  into Stu (ID, name) value (2'jack');

C. Inserting more than one piece of data

Insert  into Stu value (3'rose'), (4'John  ');

To modify the data:

A. All modifications

Update Set Age=;

B. Selective modification

Update Set name='Alice'where name='Jack  ';

Delete data:

A. Delete all data and cannot be recovered

truncate Stu;

B. Delete all data to restore

Delete  from Stu;

C. Deleting data that satisfies a condition

Delete  from where id=1;

5. Database constraints

PRIMARY KEY constraint

Create Table int Primary Key Char (ten));

Automatic growth

Create Table int Primary Key varchar (ten))

Uniqueness constraints:

Create Table int Unique Char (ten));

Non-null constraint:

Create Table int Char (notnull);

Default constraints:

Create Table int Char (default'NoName');

FOREIGN KEY constraints:

Create Table int Primary Key Char (ten)); Create Table int Primary Key Char (intforeignkeyreferences fclass (ID));

Delete the Foreign Key association table (first delete the table associated with the foreign key)

Drop Table fstudent; Drop table Fclass;  

CHECK constraints:

 create  table  tchk (id int , age int  check  ( Age >  0  and  age <  150 ), gender char  ( Span style= "color: #800000; Font-weight:bold ">10 ) check  (Gender=   " boy   '  

To increase the PRIMARY KEY constraint:

Alter Table Add constraint Primary Key (ID);

To delete a PRIMARY KEY constraint:

Alter Table Drop Primary key;

To add a FOREIGN KEY constraint:

Alter Table Add constraint Foreign Key references TPK (ID);

To delete a foreign KEY constraint:

Alter Table Drop Foreign Key fk_id

MySQL Command Collation 1