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POHow to prevent double data submission in flask-sqlalchemy
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copied!<p>I'm studying now main concepts of flask and flask-sqlalchemy. Keeping in my mind info from the tutorial (<a href="http://pythonhosted.org/Flask-SQLAlchemy/quickstart.html" rel="nofollow">intro</a> and <a href="http://pythonhosted.org/Flask-SQLAlchemy/contexts.html" rel="nofollow">contexts</a>) I'm trying to create a simple database. My Flask app is strucured as follows:</p> <pre><code>./db/ ./db/models.py ./main.py </code></pre> <p>The contents of the files is as follows:</p> <p><code>./main.py</code>:</p> <pre><code>from flask import Flask from flask.ext.sqlalchemy import SQLAlchemy app = Flask(__name__) app.config.from_object(__name__) from db.models import create_app dbapp = create_app() with dbapp.test_request_context(): from db.models import db, mumsUsers db.create_all() db.session.rollback() admin = mumsUsers("admin", "admin@example.com") db.session.add(admin) db.session.commit() </code></pre> <p><code>./db/models.py</code>:</p> <pre><code>from flask.ext.sqlalchemy import SQLAlchemy from flask import Flask, current_app db = SQLAlchemy() def create_app(): app = Flask(__name__) app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////tmp/test.db' db.init_app(app) return(app) class mumsUsers(db.Model): __tablename__ = 'mumsUsers' id = db.Column(db.Integer, primary_key=True) username = db.Column(db.String(80), unique=True) email = db.Column(db.String(80), unique=True) def __init__(self, username, email): self.username = username self.email = email def __repr__(self): return '<User %r>' % self.username </code></pre> <p>When I check the sqlite database, I see that sqlalchemy is trying to send commit() twice. So I have to remove the <em>unique=True</em> parameter in order to stop application crash. Meantime when I run the following commans from the python shell:</p> <blockquote> <blockquote> <p>admin = mumsUsers('admin', 'admin@example.com')</p> <p>db.session.add(admin)</p> <p>db.session.commit()</p> </blockquote> </blockquote> <p>only one record appears (as it is expected). </p> <p>Therefore my question is how to prevent double call for commit()?</p> <p><strong>Update</strong> The appeared problem has been caused by my fault, while making looped imports. Indeed I didn't notice I called import for the application package. Therefore please ignore this post.</p>

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