Select data from table throws error in SQLAlchemy

Question

I am a beginner trying to execute a simple web application using Pyramid and SQLAlchemy. As of now my app just returns all data stored in my table.

My views.py:

@view_config(route_name='home', renderer='templates/trial.pt')
def my_view(request):
    try:
        #str=Mystring(name="second",data="Hellostring")
        #DBSession.add(str)
        myvar=Mystring.query.order_by(Mystrings.data)

    except DBAPIError:
        return Response(conn_err_msg, content_type='text/plain', status_int=500)
    #return {'project': 'Alpy'}
    return {'myvar':myvar}

My template:-

<body>
    <div id="middle">
      <div class="middle align-right">
        <div id="left" class="app-welcome align-left">
          You can return to the
          <a href="${request.application_url}">FrontPage</a>.<br/>
<div tal:condition="myvar">
Your selection returns:<br><tal:block tal:content="myvar"></tal:block>
        </div>
    </div>
  </div>
</body>

my model.py:-

class Mystring(Base):
    __tablename__ = 'mystrings'
    id = Column(Integer, primary_key=True)
    name = Column(Text)
    data = Column(Text)

My error is: AttributeError: type object 'Mystring' has no attribute 'query'

I tried this. "myvar=DBSession.query(Mystring).all()" the error went away but I get

Your selection returns:
[alpy.models.Mystring object at xxxx, alpy.models.Mystring object at xxxxx]

which is not what i intended to get. I wanted a name value pair.

Please help.

Answer 1

You are getting a list of objects from sqlalchemy. If you just need the data, and you want to return a list of (name, data) pairs, you can do it with a list comprehension like this: return [(x.name, x.data) for x in myvar]

Note: x is just a local variable for the list comprehension, so it can be any name you like.

There is some great documentation for sqlalchemy basics at the official site, here: http://docs.sqlalchemy.org/en/rel_0_9/orm/tutorial.html

Select data from table throws error in SQLAlchemy

Question

1 answers

solution1
2 ACCPTED 2015-02-06 12:42:29

Select data from table throws error in SQLAlchemy

Question

1 answers

solution1 2 ACCPTED 2015-02-06 12:42:29

solution1
2 ACCPTED 2015-02-06 12:42:29