I am using Flask Application with flask-migrate. I have initialized the app with single database but now the requirement is to add multiple databases.
Here are the steps that I followed with the below code :-
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
import os
from flask_migrate import Migrate
basedir = os.path.abspath(os.path.dirname(__file__))
app = Flask(__name__)
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///' + os.path.join(basedir, 'database1.db')
"""
app.config['SQLALCHEMY_BINDS'] = {
'database2' : 'sqlite:///' + os.path.join(basedir, 'database2.db')
}
"""
db = SQLAlchemy(app)
migrate = Migrate(app, db)
class Table1(db.Model):
id = db.Column(db.Integer, primary_key=True)
"""
class Table2(db.Model):
__bind_key__ = 'database2'
id = db.Column(db.Integer, primary_key=True)
"""
@app.route('/add1')
def index():
item = Table1(id=2)
db.session.add(item)
db.session.commit()
return 'Added value'
"""
@app.route('/add2')
def index2():
item = Table2(id=2)
db.session.add(item)
db.session.commit()
return 'Added table2 value'
"""
if __name__ == '__main__':
app.run(debug=True)
Initialized the code as below
flask db init
flask db migrate
flask db upgrade
Visit http://127.0.0.1:5000/add1 to add to database1
Now uncomment the code so that the database2 can be added. On running flask db init again with --multidb switch, an error is reported.
(venv) bash-4.1$ flask db init --multidb
Error: Directory migrations already exists and is not empty
How can I convert an existing flask project with migrations to support multiple databases? Also, these multiple databases will evolve over the time i.e. I might have to add more databases. So, what is the best way to keep on adding more databases?
EDIT
One solution, I find is to remove the alembic_version table from existing database, remove the migrations folder and then do db init --multidb. I am okay resetting the migrations but want to know if this is the only solution?
