Create a flask ORM

Install SQLAlchemy　　

pip3 install sqlalchemy

Flask need to use the flask-sqlalchemy support package　　　　

pip3 install flask-sqlalchemy

Create a database

create database flask default charset utf8 collate utf8_general_ci;

Configure connect to the database

app.config [ 'SQLALCHEMY_DATABASE_URI'] = "mysql: // username: password @ database server address: port number / name of the database."

app.config['SQLALCHEMY_DATABASE_URI']="mysql://root:123456@localhost:3306/flask"

Create an instance of SQLAlchemy

from flask_sqlalchemy import SQLAlchemy
db = SQLAlchemy(app)

By operating in the program database db

Definition Model:

class MODELNAME(db.Model):
      __tablename__ = " the TABLENAME " # can not write, the default lowercase class name table name 
      COLUMN_NAME = db.Column (db.TYPE, the OPTIONS) # attribute name, column name correspondence table

TYPE type:　

类型名       python类型    
Integer      int            
SmallInteger int             
BigInteger   int             
Float        float          
String       str               
Text         str              
Boolean      bool              
Date         datetime.date   
Time         datetime.time   
DateTime     datetime.datetime 

OPTIONS:　　　

Option Name Description 
autoincrement if set to True indicates that the column you want to customize the growth 
primary_key if set to True indicates that the column primary key 
unique If True represents a unique value for the column 
index if set to True indicates that the value added to the index of the column is 
nullable If True to indicate that the column allows null 
default specify a default value for the column

Migration: generally do not have these two
 will create the entity classes to database: db.create_all ()

All data tables Delete all: db.drop_all ()

migrate

Start with a project manager:

from flask_script import Manager

manager = Manager(app)

manager.run()

 

After the model has been defined migration model is mapped back to the database:

from flask_migrate import Migrate,MigrateCommand

migrate = Migrate(app,db)

manager.add_command('db',MigrateCommand)

Command line:

Initialize the database, perform only once

python3 xxx.py db init

Generating an intermediate file

python3 xxx.py db migrate

Map back to database

python3 xxx.py db upgrade