Widgets

SQL queries default to displaying as a table. Other forms of display - called widgets - are also available, and are selected based on the names of the columns returned by the query.

bar_label, bar_quantity

A query that returns columns called bar_label and bar_quantity will be rendered as a simple bar chart, using Vega-Lite.

For example:

select
  county.name as bar_label,
  count(*) as bar_quantity
from location
  join county on county.id = location.county_id
group by county.name
order by count(*) desc limit 10

Or using a static list of values:

SELECT * FROM (
    VALUES (1, 'one'), (2, 'two'), (3, 'three')
) AS t (bar_quantity, bar_label);

big_number, label

If you want to display the results as a big number accompanied by a label, you can do so by returning big_number and label columns from your query, for example.

select 'Number of states' as label, count(*) as big_number from states;

markdown

Return a single column called markdown to render the contents as Markdown, for example:

select '# Number of states: ' || count(*) as markdown from states;

html

Return a single column called html to render the contents directly as HTML. This HTML is filtered using Bleach so the only tags allowed are a[href], abbr, acronym, b, blockquote, code, em, i, li, ol, strong, ul, pre, p, h1, h2, h3, h4, h5, h6.

select '<h1>Number of states: ' || count(*) || '</h1> as markdown from states;

Custom widgets

You can define your own custom widgets by creating templates with special names.

Decide on the column names that you wish to customize for, then sort them alphabetically and join them with hyphens to create your template name.

For example, you could define a widget that handles results returned as placename, geojson by creating a template called geojson-label.html.

Save that in one of your template directories as django_sql_dashboard/widgets/geojson-label.html.

Any SQL query that returns exactly the columns placename and geojson will now be rendered by your custom template file.

Within your custom template you will have access to a template variable called result with the following keys:

  • result.sql - the SQL query that is being displayed

  • rows - a list of rows, where each row is a dictionary mapping columns to their values

  • row_lists - a list of rows, where each row is a list of the values in that row

  • description - the psycopg2 cursor description

  • columns - a list of string column names

  • truncated - boolean, specifying whether the results were truncated (at 100 items) or not

  • extra_qs - extra parameters for the page encoded as a query string fragment - so if the page was loaded with state_id=5 then extra_qs would be &state_id=5. You can use this to assemble links to further queries, like the “Count” column links in the default table view.

  • duration_ms - how long the query took, in floating point milliseconds

  • templates - a list of templates that were considered for rendering this widget

You can find examples of widget templates in the templates/django_sql_dashboard/widgets directory.