The use of SQLAlchemy in Python web development-flask

SQLAlchemy is a Python ORM framework.

There is a flask-sqlalchemy extension in flask, which is convenient to use.

1. Create a sqlalchemy model module

To create a models.py module

When creating the model, first introduce the extension of Flask-sqlalchemy

from Flask Import flask
from Flask_sqlalchemy import SQLAlchemy

Then initialize the app and SQLAlchemy

App = Flask (__name__)
app.config['sqlalchemy_database_uri'sqlite:////www/db/mydb '
db = SQLAlchemy (APP)

2. Build the database

Upload the code to the Linux server, and refer to the previous write-up procedure for deploying Flask to Linux Server articles. After uploading, CD to www/directory, then execute Python, import db

From models Import db

Executive Db.create_all ()

And then we'll take a look under SQLite.

Sqlite>. Open/www/db/mydb

Sqlite>. Tables

Posts user

Sqlite>. Schema posts

CREATE TABLE Posts (

ID INTEGER not NULL,

Title VARCHAR (80),

Content VARCHAR (500),

PRIMARY KEY (ID),

UNIQUE (title),

UNIQUE (content)

);

You can see that the data table has been created.

3. Writing data

Import Posts, from models import Posts, and then execute the add command

>>> Db.session.add (Posts (' title1 ', ' content '))

>>> Db.session.add (Posts (' title2 ', ' Content2 '))

>>> Db.session.commit ()

4. Querying Data

Go to sqlite3 and check the newly added data.

Sqlite>. Open/www/db/mydb

Sqlite> SELECT * from posts;

1|title1|content

2|title2|content2

Sqlite>

At this point, the basic operation of Sqlite3 through SQLAlchemy is completed.

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The use of SQLAlchemy in Python web development-flask