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# Binary data

SQLite tables can contain binary data in `BLOB` columns.

Datasette includes special handling for these binary values. The Datasette interface detects binary values and provides a link to download their content, for example on https://latest.datasette.io/fixtures/binary_data

Screenshot showing download links next to binary data in the table view

Binary data is represented in `.json` exports using Base64 encoding.

https://latest.datasette.io/fixtures/binary_data.json?_shape=array

    [
        {
            "rowid": 1,
            "data": {
                "$base64": true,
                "encoded": "FRwCx60F/g=="
            }
        },
        {
            "rowid": 2,
            "data": {
                "$base64": true,
                "encoded": "FRwDx60F/g=="
            }
        },
        {
            "rowid": 3,
            "data": null
        }
    ]

## Linking to binary downloads

The `.blob` output format is used to return binary data. It requires a `_blob_column=` query string argument specifying which BLOB column should be downloaded, for example:

https://latest.datasette.io/fixtures/binary_data/1.blob?_blob_column=data

This output format can also be used to return binary data from an arbitrary SQL query. Since such queries do not specify an exact row, an additional `?_blob_hash=` parameter can be used to specify the SHA-256 hash of the value that is being linked to.

Consider the query `select data from binary_data` - demonstrated here.

That page links to the binary value downloads. Those links look like this:

https://latest.datasette.io/fixtures.blob?sql=select+data+from+binary_data&_blob_column=data&_blob_hash=f3088978da8f9aea479ffc7f631370b968d2e855eeb172bea7f6c7a04262bb6d

These `.blob` links are also returned in the `.csv` exports Datasette provides for binary tables and queries, since the CSV format does not have a mechanism for representing binary data.

## Binary plugins

Several Datasette plugins are available that change the way Datasette treats binary data.

- datasette-render-binary modifies Datasette's default interface to show an automatic guess at what type of binary data is being stored, along with a visual representation of the binary value that displays ASCII strings directly in the interface.

- datasette-render-images detects common image formats and renders them as images directly in the Datasette interface.

- datasette-media allows Datasette interfaces to be configured to serve binary files from configured SQL queries, and includes the ability to resize images directly before serving them.