kopia lustrzana https://github.com/simonw/datasette
64 wiersze
2.6 KiB
ReStructuredText
64 wiersze
2.6 KiB
ReStructuredText
.. _csv_export:
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CSV Export
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==========
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Any Datasette table, view or custom SQL query can be exported as CSV.
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To obtain the CSV representation of the table you are looking, click the "this
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data as CSV" link.
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You can also use the advanced export form for more control over the resulting
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file, which looks like this and has the following options:
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.. image:: advanced_export.png
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* **download file** - instead of displaying CSV in your browser, this forces
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your browser to download the CSV to your downloads directory.
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* **expand labels** - if your table has any foreign key references this option
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will cause the CSV to gain additional ``COLUMN_NAME_label`` columns with a
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label for each foreign key derived from the linked table. `In this example
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<https://latest.datasette.io/fixtures/facetable.csv?_labels=on&_size=max>`_
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the ``city_id`` column is accompanied by a ``city_id_label`` column.
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* **stream all rows** - by default CSV files only contain the first
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:ref:`config_max_returned_rows` records. This option will cause Datasette to
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loop through every matching record and return them as a single CSV file.
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You can try that out on https://latest.datasette.io/fixtures/facetable?_size=4
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Streaming all records
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---------------------
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The *stream all rows* option is designed to be as efficient as possible -
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under the hood it takes advantage of Python 3 asyncio capabilities and
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Datasette's efficient :ref:`pagination <pagination>` to stream back the full
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CSV file.
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Since databases can get pretty large, by default this option is capped at 100MB -
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if a table returns more than 100MB of data the last line of the CSV will be a
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truncation error message.
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You can increase or remove this limit using the :ref:`config_max_csv_mb` config
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setting. You can also disable the CSV export feature entirely using
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:ref:`config_allow_csv_stream`.
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A note on URLs
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--------------
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The default URL for the CSV representation of a table is that table with
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``.csv`` appended to it:
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* https://latest.datasette.io/fixtures/facetable - HTML interface
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* https://latest.datasette.io/fixtures/facetable.csv - CSV export
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* https://latest.datasette.io/fixtures/facetable.json - JSON API
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This pattern doesn't work for tables with names that already end in ``.csv`` or
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``.json``. For those tables, you can instead use the ``_format=`` querystring
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parameter:
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* https://latest.datasette.io/fixtures/table%2Fwith%2Fslashes.csv - HTML interface
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* https://latest.datasette.io/fixtures/table%2Fwith%2Fslashes.csv?_format=csv - CSV export
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* https://latest.datasette.io/fixtures/table%2Fwith%2Fslashes.csv?_format=json - JSON API
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