My application uses a combination of Flask, Flask-SQLAlchemy, Flask-WTF and Jinja2.
In its current incarnation, I have a settings table. The table will only have one record with one field. Initially the table contains zero records.
What I want to achieve is:
Here is my code:
models.py
class Provider(db.Model):
id = db.Column(db.Integer, primary_key = True)
rssfeed = db.Column(db.String(120), unique = True)
def __init__(self, rssfeed):
self.rssfeed = rssfeed
def __repr__(self):
return '<NZBMatrix feed url %r>' % self.rssfeed
forms.py
class SettingsForm(Form):
rssfeed = TextField('rssfed', validators= [Required()])
views.py
@app.route('/settings', methods=["GET","POST"])
def settings():
""" show settings """
provider = Provider.query.get(1)
form = SettingsForm(obj=provider)
print provider
if request.method == "POST" and form.validate():
if Provider.query.get(1) is None:
provider = Provider(rssfeed=form.rssfeed.data)
form.populate_obj(provider)
db.session.add(provider)
db.session.commit()
flash("Settings added")
return render_template("settings.html", form=form)
As it stands this code creates a record if it doesn't exists but the rssfeed
column is empty.
How can I change this code so that it will INSERT
if the record doesn't exist and UPDATE
if it does?
Once your form is validated etc,
To add a new record:
new_provider = Provider(form.rssfeed.data)
db.session.add(new_provider)
db.session.commit()
To update an existing record:
existing_provider = Provider.query.get(1) # or whatever
# update the rssfeed column
existing_provider.rssfeed = form.rssfeed.data
db.session.commit()
The trick in updating is that you just have to change the particular field and do a commit. rest is taken care by the db session. I think you are using the merge function which is now deprecated in SQLAlchemy.