Support column descriptions in metadata.json

Could look something like this:

{
    "title": "Five Thirty Eight",
    "license": "CC Attribution 4.0 License",
    "license_url": "https://creativecommons.org/licenses/by/4.0/",
    "source": "fivethirtyeight/data on GitHub",
    "source_url": "https://github.com/fivethirtyeight/data",
    "databases": {
        "fivethirtyeight": {
            "tables": {
                "mueller-polls/mueller-approval-polls": {
                    "description_html": "<p>....</p>",
                    "columns": {
                        "name_of_column": "column_description goes here"
}

[simonw]

I’m going with "columns": {"name-of-column": "description-of-column"}.

If I decide to make "col" and "nocol" available in metadata I’ll use those as the keys in the metadata, for consistency with the existing query string parameters.

I’m OK with having both "columns": ... and "col": ... keys in the metadata, even though they could be a tiny bit confusing without the documentation.

[simonw]

My idea is that if you installed my proposed plugin you wouldn’t need metadata.json at all - your metadata would instead live in a table in the connected SQLite database files - either one table per database (so the metadata can live in the same place as the data) or maybe also in a dedicated separate database file, for if you want to add metadata to an otherwise read-only database.

The plugin would then provide a UI for editing that metadata - maybe by configuring some writable canned queries or maybe something more custom than that. Or you could edit the metadata by manually editing the SQLite database file (or loading data into it using a tool like yaml-to-sqlite).