flask sqlalchemy未知数据库错误

Question

I'm trying to create a Web application using flask and flask-sqlalchemy, i have the following code

    from flask.ext.sqlalchemy import  SQLAlchemy
    from flask import Flask

    app= Flask(__name__)
    app.config['SQLALCHEMY_DATABASE_URI']=            'mysql+mysqldb://root:presario@127.0.0.1/testdb'
    db = SQLAlchemy(app)

When i run db.create_all() from command line, i get unknown database 'testdb' error I'm working on ubuntu but the code above works on my windows machine.

I've tried adding the port number, removing the python connector but nothing works. below is the stack trace

 File "/usr/lib/python2.7/dist-packages/MySQLdb/__init__.py", line 81, in Connect
     return Connection(*args, **kwargs)
 File "/usr/lib/python2.7/dist-packages/MySQLdb/connections.py", line 187, in __init__
     super(Connection, self).__init__(*args, **kwargs2)
 sqlalchemy.exc.OperationalError: (OperationalError) (1049, "Unknown database 'testdb'") None None

Answer 1

I would suggest that the database 'testdb' does not exist.

SQLAlchemy will not actually create the database for you. You have to connect to an existing database. It will then create all the tables.

Joe

Answer 2

You can create DB like this:

url = 'mysql://%s:%s@%s' % (USER, PASSWORD, HOST)
engine = sqlalchemy.create_engine(url)  # connect to server

create_str = "CREATE DATABASE IF NOT EXISTS %s ;" % (DATABASE)
engine.execute(create_str)
engine.execute("USE location;")
db.create_all()
db.session.commit()