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
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:
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 <https://latest.datasette.io/fixtures?sql=select+data+from+binary_data>`__.
That page links to the binary value downloads. Those links look like this:
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 <https://github.com/simonw/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 <https://github.com/simonw/datasette-render-images>`__ detects common image formats and renders them as images directly in the Datasette interface.
-`datasette-media <https://github.com/simonw/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.