Read

Reading SQLAlchemy models in views is simple.

Model List View

See also

• flask_velox.mixins.sqla.read.ListModelMixin

The ModelListView allows you to render templates with paginated (or not) lists of model objects.

from flask.ext.velox.views.sqla import read
from yourapp.models import Model

class MyView(read.ModelListView):
    model = Model
    template = 'list.html'

The context returned to the template is as follows:

• model: The SQLAlchemy model class
• objects: List of objects returned from query
• pagination: Pagination object or None

Pagination

Flask-SQLAlchemy gives us pagination if we want it, by default paginate is True and the number of records is limited to 30, but this can all be changed and configured.

No Pagination

class MyView(read.ModelListView):
    model = Model
    template = 'list.html'
    paginate = False

Set records per page

class MyView(read.ModelListView):
    model = Model
    template = 'list.html'
    per_page = 10

Example Template

Here are some example templates.

Without Pagination

<ul>
    {% for object in objects %}
    <li>{{ object.name }}</li>
    {% endfor %}
</ul>

With Pagination

<ul>
    {% for object in objects %}
    <li>{{ object.name }}</li>
    {% endfor %}
</ul>

{% if objects.has_prev %}<a href="{{ url_for('rule', page=objects.prev_num) }}"><< Newer Objects{% else %}<< Newer Objects{% endif %} |
{% if objects.has_next %}<a href="{{ url_for('rule', page=objects.next_num) }}">Older Objects >></a>{% else %}Older Objects >>{% endif %}

Changing context name

If you do not wish objects to be used as the context name for your object list you can change this be defining a objects_context_name attribute on the class, for example:

from flask.ext.velox.views.sqla import read
from yourapp.models import Model

class MyView(read.ModelListView):
    model = Model
    objects_context_name = 'foos'
    template = 'list.html'

In this case foos will be used instead of objects in the template.

Model Table View

The table model view is almost exactly the same as ModelListView so we won’t tread the same ground.

This view allows us to specify the columns we want to render in our table which relate to field names in the model:

from flask.ext.velox.views.sqla import read
from yourapp.models import Model

class MyView(read.ModelTableView):
    model = Model
    template = 'list.html'
    columns = ['field1', 'field2', 'field3']
    paginate = False

The context returned to the template is as follows:

• model: The SQLAlchemy model class
• objects: List of objects returned from query
• pagination: Pagination object or None
• columns: List of columns to render
• column_name: Function to make the column name humanized
• format_value: Function to format a fields value

Template Example

<table>
    <thead>
        <tr>
            {% for column in columns %}
            <th>{{ column_name(column) }}</th>
            {% endfor %}
        </tr>
    </thead>
    <tbody>
        {% for object in objects %}
        <tr>
            {% for column in columns %}
            <tr>{{ format_value(column, object) }}
            {% endfor %}
        </tr>
        {% endfor %}
    </tbody>
</table>

We won’t go into detail about how column_name and format_value work here but you can check the API Reference for more details:

• flask_velox.mixins.sqla.read.TableModelMixin.column_name()
• flask_velox.mixins.sqla.read.TableModelMixin.format_value()

Pagination operates exactly the same as ListModelMixin.

Object View

The ObjectView functions like the list views above however simply returns a single object to the template. Please read the SingleObjectMixin documentation which explains how an object is retreived.

See also

• flask_velox.mixins.sqla.read.ObjectMixin
• flask_velox.mixins.sqla.object.SingleObjectMixin

from flask.ext.velox.views.sqla import read
from yourapp.models import Model

class MyView(read.ObjectView):
    model = Model
    template = 'detail.html'

The context returned to the template is as follows:

• model: The SQLAlchemy model class
• object: The object

Example Template

<html>
    <head>
        <meta charset="utf-8" />
        <title>{{ object.name }}</title>
    </head>
    <body>
        {{ object.description }}
    </body>
</html>

Changing context name

As with the list views you can change the context name used for accessing the object in the template by setting an object_context_name attribute on the view class:

from flask.ext.velox.views.sqla import read
from yourapp.models import Model

class MyView(read.ObjectView):
    model = Model
    template = 'detail.html'
    object_context_name = 'foo'

In the above view foo will be returned to the template for accessing the object rather than object.