{"id": "performance:performance-inspect", "page": "performance", "ref": "performance-inspect", "title": "Using \"datasette inspect\"", "content": "Counting the rows in a table can be a very expensive operation on larger databases. In immutable mode Datasette performs this count only once and caches the results, but this can still cause server startup time to increase by several seconds or more. \n If you know that a database is never going to change you can precalculate the table row counts once and store then in a JSON file, then use that file when you later start the server. \n To create a JSON file containing the calculated row counts for a database, use the following: \n datasette inspect data.db --inspect-file=counts.json \n Then later you can start Datasette against the counts.json file and use it to skip the row counting step and speed up server startup: \n datasette -i data.db --inspect-file=counts.json \n You need to use the -i immutable mode against the database file here or the counts from the JSON file will be ignored. \n You will rarely need to use this optimization in every-day use, but several of the datasette publish commands described in Publishing data use this optimization for better performance when deploying a database file to a hosting provider.", "breadcrumbs": "[\"Performance and caching\"]", "references": "[]"} {"id": "performance:performance-immutable-mode", "page": "performance", "ref": "performance-immutable-mode", "title": "Immutable mode", "content": "If you can be certain that a SQLite database file will not be changed by another process you can tell Datasette to open that file in immutable mode . \n Doing so will disable all locking and change detection, which can result in improved query performance. \n This also enables further optimizations relating to HTTP caching, described below. \n To open a file in immutable mode pass it to the datasette command using the -i option: \n datasette -i data.db \n When you open a file in immutable mode like this Datasette will also calculate and cache the row counts for each table in that database when it first starts up, further improving performance.", "breadcrumbs": "[\"Performance and caching\"]", "references": "[]"} {"id": "performance:performance-hashed-urls", "page": "performance", "ref": "performance-hashed-urls", "title": "datasette-hashed-urls", "content": "If you open a database file in immutable mode using the -i option, you can be assured that the content of that database will not change for the lifetime of the Datasette server. \n The datasette-hashed-urls plugin implements an optimization where your database is served with part of the SHA-256 hash of the database contents baked into the URL. \n A database at /fixtures will instead be served at /fixtures-aa7318b , and a year-long cache expiry header will be returned with those pages. \n This will then be cached by both browsers and caching proxies such as Cloudflare or Fastly, providing a potentially significant performance boost. \n To install the plugin, run the following: \n datasette install datasette-hashed-urls \n \n Prior to Datasette 0.61 hashed URL mode was a core Datasette feature, enabled using the hash_urls setting. This implementation has now been removed in favor of the datasette-hashed-urls plugin. \n Prior to Datasette 0.28 hashed URL mode was the default behaviour for Datasette, since all database files were assumed to be immutable and unchanging. From 0.28 onwards the default has been to treat database files as mutable unless explicitly configured otherwise.", "breadcrumbs": "[\"Performance and caching\"]", "references": "[{\"href\": \"https://datasette.io/plugins/datasette-hashed-urls\", \"label\": \"datasette-hashed-urls plugin\"}]"} {"id": "performance:performance", "page": "performance", "ref": "performance", "title": "Performance and caching", "content": "Datasette runs on top of SQLite, and SQLite has excellent performance. For small databases almost any query should return in just a few milliseconds, and larger databases (100s of MBs or even GBs of data) should perform extremely well provided your queries make sensible use of database indexes. \n That said, there are a number of tricks you can use to improve Datasette's performance.", "breadcrumbs": "[]", "references": "[]"} {"id": "performance:http-caching", "page": "performance", "ref": "http-caching", "title": "HTTP caching", "content": "If your database is immutable and guaranteed not to change, you can gain major performance improvements from Datasette by enabling HTTP caching. \n This can work at two different levels. First, it can tell browsers to cache the results of queries and serve future requests from the browser cache. \n More significantly, it allows you to run Datasette behind a caching proxy such as Varnish or use a cache provided by a hosted service such as Fastly or Cloudflare . This can provide incredible speed-ups since a query only needs to be executed by Datasette the first time it is accessed - all subsequent hits can then be served by the cache. \n Using a caching proxy in this way could enable a Datasette-backed visualization to serve thousands of hits a second while running Datasette itself on extremely inexpensive hosting. \n Datasette's integration with HTTP caches can be enabled using a combination of configuration options and query string arguments. \n The default_cache_ttl setting sets the default HTTP cache TTL for all Datasette pages. This is 5 seconds unless you change it - you can set it to 0 if you wish to disable HTTP caching entirely. \n You can also change the cache timeout on a per-request basis using the ?_ttl=10 query string parameter. This can be useful when you are working with the Datasette JSON API - you may decide that a specific query can be cached for a longer time, or maybe you need to set ?_ttl=0 for some requests for example if you are running a SQL order by random() query.", "breadcrumbs": "[\"Performance and caching\"]", "references": "[{\"href\": \"https://varnish-cache.org/\", \"label\": \"Varnish\"}, {\"href\": \"https://www.fastly.com/\", \"label\": \"Fastly\"}, {\"href\": \"https://www.cloudflare.com/\", \"label\": \"Cloudflare\"}]"} {"id": "pages:tableview", "page": "pages", "ref": "tableview", "title": "Table", "content": "The table page is the heart of Datasette: it allows users to interactively explore the contents of a database table, including sorting, filtering, Full-text search and applying Facets . \n The HTML interface is worth spending some time exploring. As with other pages, you can return the JSON data by appending .json to the URL path, before any ? query string arguments. \n The query string arguments are described in more detail here: Table arguments \n You can also use the table page to interactively construct a SQL query - by applying different filters and a sort order for example - and then click the \"View and edit SQL\" link to see the SQL query that was used for the page and edit and re-submit it. \n Some examples: \n \n \n ../items lists all of the line-items registered by UK MPs as potential conflicts of interest. It demonstrates Datasette's support for Full-text search . \n \n \n ../antiquities-act%2Factions_under_antiquities_act is an interface for exploring the \"actions under the antiquities act\" data table published by FiveThirtyEight. \n \n \n ../global-power-plants?country_long=United+Kingdom&primary_fuel=Gas is a filtered table page showing every Gas power plant in the United Kingdom. It includes some default facets (configured using its metadata.json ) and uses the datasette-cluster-map plugin to show a map of the results.", "breadcrumbs": "[\"Pages and API endpoints\"]", "references": "[{\"href\": \"https://register-of-members-interests.datasettes.com/regmem/items\", \"label\": \"../items\"}, {\"href\": \"https://fivethirtyeight.datasettes.com/fivethirtyeight/antiquities-act%2Factions_under_antiquities_act\", \"label\": \"../antiquities-act%2Factions_under_antiquities_act\"}, {\"href\": \"https://global-power-plants.datasettes.com/global-power-plants/global-power-plants?_facet=primary_fuel&_facet=owner&_facet=country_long&country_long__exact=United+Kingdom&primary_fuel=Gas\", \"label\": \"../global-power-plants?country_long=United+Kingdom&primary_fuel=Gas\"}, {\"href\": \"https://global-power-plants.datasettes.com/-/metadata\", \"label\": \"its metadata.json\"}, {\"href\": \"https://github.com/simonw/datasette-cluster-map\", \"label\": \"datasette-cluster-map\"}]"} {"id": "pages:rowview", "page": "pages", "ref": "rowview", "title": "Row", "content": "Every row in every Datasette table has its own URL. This means individual records can be linked to directly. \n Table cells with extremely long text contents are truncated on the table view according to the truncate_cells_html setting. If a cell has been truncated the full length version of that cell will be available on the row page. \n Rows which are the targets of foreign key references from other tables will show a link to a filtered search for all records that reference that row. Here's an example from the Registers of Members Interests database: \n ../people/uk.org.publicwhip%2Fperson%2F10001 \n Note that this URL includes the encoded primary key of the record. \n Here's that same page as JSON: \n ../people/uk.org.publicwhip%2Fperson%2F10001.json", "breadcrumbs": "[\"Pages and API endpoints\"]", "references": "[{\"href\": \"https://register-of-members-interests.datasettes.com/regmem/people/uk.org.publicwhip%2Fperson%2F10001\", \"label\": \"../people/uk.org.publicwhip%2Fperson%2F10001\"}, {\"href\": \"https://register-of-members-interests.datasettes.com/regmem/people/uk.org.publicwhip%2Fperson%2F10001.json\", \"label\": \"../people/uk.org.publicwhip%2Fperson%2F10001.json\"}]"} {"id": "pages:pages", "page": "pages", "ref": "pages", "title": "Pages and API endpoints", "content": "The Datasette web application offers a number of different pages that can be accessed to explore the data in question, each of which is accompanied by an equivalent JSON API.", "breadcrumbs": "[]", "references": "[]"} {"id": "pages:indexview", "page": "pages", "ref": "indexview", "title": "Top-level index", "content": "The root page of any Datasette installation is an index page that lists all of the currently attached databases. Some examples: \n \n \n fivethirtyeight.datasettes.com \n \n \n global-power-plants.datasettes.com \n \n \n register-of-members-interests.datasettes.com \n \n \n Add /.json to the end of the URL for the JSON version of the underlying data: \n \n \n fivethirtyeight.datasettes.com/.json \n \n \n global-power-plants.datasettes.com/.json \n \n \n register-of-members-interests.datasettes.com/.json", "breadcrumbs": "[\"Pages and API endpoints\"]", "references": "[{\"href\": \"https://fivethirtyeight.datasettes.com/\", \"label\": \"fivethirtyeight.datasettes.com\"}, {\"href\": \"https://global-power-plants.datasettes.com/\", \"label\": \"global-power-plants.datasettes.com\"}, {\"href\": \"https://register-of-members-interests.datasettes.com/\", \"label\": \"register-of-members-interests.datasettes.com\"}, {\"href\": \"https://fivethirtyeight.datasettes.com/.json\", \"label\": \"fivethirtyeight.datasettes.com/.json\"}, {\"href\": \"https://global-power-plants.datasettes.com/.json\", \"label\": \"global-power-plants.datasettes.com/.json\"}, {\"href\": \"https://register-of-members-interests.datasettes.com/.json\", \"label\": \"register-of-members-interests.datasettes.com/.json\"}]"} {"id": "pages:databaseview", "page": "pages", "ref": "databaseview", "title": "Database", "content": "Each database has a page listing the tables, views and canned queries available for that database. If the execute-sql permission is enabled (it's on by default) there will also be an interface for executing arbitrary SQL select queries against the data. \n Examples: \n \n \n fivethirtyeight.datasettes.com/fivethirtyeight \n \n \n global-power-plants.datasettes.com/global-power-plants \n \n \n The JSON version of this page provides programmatic access to the underlying data: \n \n \n fivethirtyeight.datasettes.com/fivethirtyeight.json \n \n \n global-power-plants.datasettes.com/global-power-plants.json", "breadcrumbs": "[\"Pages and API endpoints\"]", "references": "[{\"href\": \"https://fivethirtyeight.datasettes.com/fivethirtyeight\", \"label\": \"fivethirtyeight.datasettes.com/fivethirtyeight\"}, {\"href\": \"https://global-power-plants.datasettes.com/global-power-plants\", \"label\": \"global-power-plants.datasettes.com/global-power-plants\"}, {\"href\": \"https://fivethirtyeight.datasettes.com/fivethirtyeight.json\", \"label\": \"fivethirtyeight.datasettes.com/fivethirtyeight.json\"}, {\"href\": \"https://global-power-plants.datasettes.com/global-power-plants.json\", \"label\": \"global-power-plants.datasettes.com/global-power-plants.json\"}]"} {"id": "metadata:specifying-units-for-a-column", "page": "metadata", "ref": "specifying-units-for-a-column", "title": "Specifying units for a column", "content": "Datasette supports attaching units to a column, which will be used when displaying\n values from that column. SI prefixes will be used where appropriate. \n Column units are configured in the metadata like so: \n {\n \"databases\": {\n \"database1\": {\n \"tables\": {\n \"example_table\": {\n \"units\": {\n \"column1\": \"metres\",\n \"column2\": \"Hz\"\n }\n }\n }\n }\n }\n} \n Units are interpreted using Pint , and you can see the full list of available units in\n Pint's unit registry . You can also add custom units to the metadata, which will be\n registered with Pint: \n {\n \"custom_units\": [\n \"decibel = [] = dB\"\n ]\n}", "breadcrumbs": "[\"Metadata\"]", "references": "[{\"href\": \"https://pint.readthedocs.io/\", \"label\": \"Pint\"}, {\"href\": \"https://github.com/hgrecco/pint/blob/master/pint/default_en.txt\", \"label\": \"unit registry\"}, {\"href\": \"http://pint.readthedocs.io/en/latest/defining.html\", \"label\": \"custom units\"}]"} {"id": "metadata:per-database-and-per-table-metadata", "page": "metadata", "ref": "per-database-and-per-table-metadata", "title": "Per-database and per-table metadata", "content": "Metadata at the top level of the JSON will be shown on the index page and in the\n footer on every page of the site. The license and source is expected to apply to\n all of your data. \n You can also provide metadata at the per-database or per-table level, like this: \n {\n \"databases\": {\n \"database1\": {\n \"source\": \"Alternative source\",\n \"source_url\": \"http://example.com/\",\n \"tables\": {\n \"example_table\": {\n \"description_html\": \"Custom table description\",\n \"license\": \"CC BY 3.0 US\",\n \"license_url\": \"https://creativecommons.org/licenses/by/3.0/us/\"\n }\n }\n }\n }\n} \n Each of the top-level metadata fields can be used at the database and table level.", "breadcrumbs": "[\"Metadata\"]", "references": "[]"} {"id": "metadata:metadata-yaml", "page": "metadata", "ref": "metadata-yaml", "title": "Using YAML for metadata", "content": "Datasette accepts YAML as an alternative to JSON for your metadata configuration file. YAML is particularly useful for including multiline HTML and SQL strings. \n Here's an example of a metadata.yml file, re-using an example from Canned queries . \n title: Demonstrating Metadata from YAML\ndescription_html: |-\n
This description includes a long HTML string
\nThis demonstrates basic LIKE search \n The metadata.yml file is passed to Datasette using the same --metadata option: \n datasette fixtures.db --metadata metadata.yml", "breadcrumbs": "[\"Metadata\"]", "references": "[]"}
{"id": "metadata:metadata-source-license-about", "page": "metadata", "ref": "metadata-source-license-about", "title": "Source, license and about", "content": "The three visible metadata fields you can apply to everything, specific databases or specific tables are source, license and about. All three are optional. \n source and source_url should be used to indicate where the underlying data came from. \n license and license_url should be used to indicate the license under which the data can be used. \n about and about_url can be used to link to further information about the project - an accompanying blog entry for example. \n For each of these you can provide just the *_url field and Datasette will treat that as the default link label text and display the URL directly on the page.", "breadcrumbs": "[\"Metadata\"]", "references": "[]"}
{"id": "metadata:metadata-sortable-columns", "page": "metadata", "ref": "metadata-sortable-columns", "title": "Setting which columns can be used for sorting", "content": "Datasette allows any column to be used for sorting by default. If you need to\n control which columns are available for sorting you can do so using the optional\n sortable_columns key: \n {\n \"databases\": {\n \"database1\": {\n \"tables\": {\n \"example_table\": {\n \"sortable_columns\": [\n \"height\",\n \"weight\"\n ]\n }\n }\n }\n }\n} \n This will restrict sorting of example_table to just the height and\n weight columns. \n You can also disable sorting entirely by setting \"sortable_columns\": [] \n You can use sortable_columns to enable specific sort orders for a view called name_of_view in the database my_database like so: \n {\n \"databases\": {\n \"my_database\": {\n \"tables\": {\n \"name_of_view\": {\n \"sortable_columns\": [\n \"clicks\",\n \"impressions\"\n ]\n }\n }\n }\n }\n}", "breadcrumbs": "[\"Metadata\"]", "references": "[]"}
{"id": "metadata:metadata-page-size", "page": "metadata", "ref": "metadata-page-size", "title": "Setting a custom page size", "content": "Datasette defaults to displaying 100 rows per page, for both tables and views. You can change this default page size on a per-table or per-view basis using the \"size\" key in metadata.json : \n {\n \"databases\": {\n \"mydatabase\": {\n \"tables\": {\n \"example_table\": {\n \"size\": 10\n }\n }\n }\n }\n} \n This size can still be over-ridden by passing e.g. ?_size=50 in the query string.", "breadcrumbs": "[\"Metadata\"]", "references": "[]"}
{"id": "metadata:metadata-hiding-tables", "page": "metadata", "ref": "metadata-hiding-tables", "title": "Hiding tables", "content": "You can hide tables from the database listing view (in the same way that FTS and\n SpatiaLite tables are automatically hidden) using \"hidden\": true : \n {\n \"databases\": {\n \"database1\": {\n \"tables\": {\n \"example_table\": {\n \"hidden\": true\n }\n }\n }\n }\n}", "breadcrumbs": "[\"Metadata\"]", "references": "[]"}
{"id": "metadata:metadata-default-sort", "page": "metadata", "ref": "metadata-default-sort", "title": "Setting a default sort order", "content": "By default Datasette tables are sorted by primary key. You can over-ride this default for a specific table using the \"sort\" or \"sort_desc\" metadata properties: \n {\n \"databases\": {\n \"mydatabase\": {\n \"tables\": {\n \"example_table\": {\n \"sort\": \"created\"\n }\n }\n }\n }\n} \n Or use \"sort_desc\" to sort in descending order: \n {\n \"databases\": {\n \"mydatabase\": {\n \"tables\": {\n \"example_table\": {\n \"sort_desc\": \"created\"\n }\n }\n }\n }\n}", "breadcrumbs": "[\"Metadata\"]", "references": "[]"}
{"id": "metadata:metadata-column-descriptions", "page": "metadata", "ref": "metadata-column-descriptions", "title": "Column descriptions", "content": "You can include descriptions for your columns by adding a \"columns\": {\"name-of-column\": \"description-of-column\"} block to your table metadata: \n {\n \"databases\": {\n \"database1\": {\n \"tables\": {\n \"example_table\": {\n \"columns\": {\n \"column1\": \"Description of column 1\",\n \"column2\": \"Description of column 2\"\n }\n }\n }\n }\n }\n} \n These will be displayed at the top of the table page, and will also show in the cog menu for each column. \n You can see an example of how these look at latest.datasette.io/fixtures/roadside_attractions .", "breadcrumbs": "[\"Metadata\"]", "references": "[{\"href\": \"https://latest.datasette.io/fixtures/roadside_attractions\", \"label\": \"latest.datasette.io/fixtures/roadside_attractions\"}]"}
{"id": "metadata:label-columns", "page": "metadata", "ref": "label-columns", "title": "Specifying the label column for a table", "content": "Datasette's HTML interface attempts to display foreign key references as\n labelled hyperlinks. By default, it looks for referenced tables that only have\n two columns: a primary key column and one other. It assumes that the second\n column should be used as the link label. \n If your table has more than two columns you can specify which column should be\n used for the link label with the label_column property: \n {\n \"databases\": {\n \"database1\": {\n \"tables\": {\n \"example_table\": {\n \"label_column\": \"title\"\n }\n }\n }\n }\n}", "breadcrumbs": "[\"Metadata\"]", "references": "[]"}
{"id": "metadata:id1", "page": "metadata", "ref": "id1", "title": "Metadata", "content": "Data loves metadata. Any time you run Datasette you can optionally include a\n JSON file with metadata about your databases and tables. Datasette will then\n display that information in the web UI. \n Run Datasette like this: \n datasette database1.db database2.db --metadata metadata.json \n Your metadata.json file can look something like this: \n {\n \"title\": \"Custom title for your index page\",\n \"description\": \"Some description text can go here\",\n \"license\": \"ODbL\",\n \"license_url\": \"https://opendatacommons.org/licenses/odbl/\",\n \"source\": \"Original Data Source\",\n \"source_url\": \"http://example.com/\"\n} \n You can optionally use YAML instead of JSON, see Using YAML for metadata . \n The above metadata will be displayed on the index page of your Datasette-powered\n site. The source and license information will also be included in the footer of\n every page served by Datasette. \n Any special HTML characters in description will be escaped. If you want to\n include HTML in your description, you can use a description_html property\n instead.", "breadcrumbs": "[]", "references": "[]"}
{"id": "json_api:json-api-table-arguments", "page": "json_api", "ref": "json-api-table-arguments", "title": "Special table arguments", "content": "?_col=COLUMN1&_col=COLUMN2 \n \n List specific columns to display. These will be shown along with any primary keys. \n \n \n \n ?_nocol=COLUMN1&_nocol=COLUMN2 \n \n List specific columns to hide - any column not listed will be displayed. Primary keys cannot be hidden. \n \n \n \n ?_labels=on/off \n \n Expand foreign key references for every possible column. See below. \n \n \n \n ?_label=COLUMN1&_label=COLUMN2 \n \n Expand foreign key references for one or more specified columns. \n \n \n \n ?_size=1000 or ?_size=max \n \n Sets a custom page size. This cannot exceed the max_returned_rows limit\n passed to datasette serve . Use max to get max_returned_rows . \n \n \n \n ?_sort=COLUMN \n \n Sorts the results by the specified column. \n \n \n \n ?_sort_desc=COLUMN \n \n Sorts the results by the specified column in descending order. \n \n \n \n ?_search=keywords \n \n For SQLite tables that have been configured for\n full-text search executes a search\n with the provided keywords. \n \n \n \n ?_search_COLUMN=keywords \n \n Like _search= but allows you to specify the column to be searched, as\n opposed to searching all columns that have been indexed by FTS. \n \n \n \n ?_searchmode=raw \n \n With this option, queries passed to ?_search= or ?_search_COLUMN= will\n not have special characters escaped. This means you can make use of the full\n set of advanced SQLite FTS syntax ,\n though this could potentially result in errors if the wrong syntax is used. \n \n \n \n ?_where=SQL-fragment \n \n If the execute-sql permission is enabled, this parameter\n can be used to pass one or more additional SQL fragments to be used in the\n WHERE clause of the SQL used to query the table. \n This is particularly useful if you are building a JavaScript application\n that needs to do something creative but still wants the other conveniences\n provided by the table view (such as faceting) and hence would like not to\n have to construct a completely custom SQL query. \n Some examples: \n \n \n facetable?_where=_neighborhood like \"%c%\"&_where=_city_id=3 \n \n \n facetable?_where=_city_id in (select id from facet_cities where name != \"Detroit\") \n \n \n \n \n \n ?_through={json} \n \n This can be used to filter rows via a join against another table. \n The JSON parameter must include three keys: table , column and value . \n table must be a table that the current table is related to via a foreign key relationship. \n column must be a column in that other table. \n value is the value that you want to match against. \n For example, to filter roadside_attractions to just show the attractions that have a characteristic of \"museum\", you would construct this JSON: \n {\n \"table\": \"roadside_attraction_characteristics\",\n \"column\": \"characteristic_id\",\n \"value\": \"1\"\n} \n As a URL, that looks like this: \n ?_through={%22table%22:%22roadside_attraction_characteristics%22,%22column%22:%22characteristic_id%22,%22value%22:%221%22} \n Here's an example . \n \n \n \n ?_next=TOKEN \n \n Pagination by continuation token - pass the token that was returned in the\n \"next\" property by the previous page. \n \n \n \n ?_facet=column \n \n Facet by column. Can be applied multiple times, see Facets . Only works on the default JSON output, not on any of the custom shapes. \n \n \n \n ?_facet_size=100 \n \n Increase the number of facet results returned for each facet. Use ?_facet_size=max for the maximum available size, determined by max_returned_rows . \n \n \n \n ?_nofacet=1 \n \n Disable all facets and facet suggestions for this page, including any defined by Facets in metadata.json . \n \n \n \n ?_nosuggest=1 \n \n Disable facet suggestions for this page. \n \n \n \n ?_nocount=1 \n \n Disable the select count(*) query used on this page - a count of None will be returned instead.", "breadcrumbs": "[\"JSON API\", \"Table arguments\"]", "references": "[{\"href\": \"https://www.sqlite.org/fts3.html\", \"label\": \"full-text search\"}, {\"href\": \"https://www.sqlite.org/fts5.html#full_text_query_syntax\", \"label\": \"advanced SQLite FTS syntax\"}, {\"href\": \"https://latest.datasette.io/fixtures/facetable?_where=_neighborhood%20like%20%22%c%%22&_where=_city_id=3\", \"label\": \"facetable?_where=_neighborhood like \\\"%c%\\\"&_where=_city_id=3\"}, {\"href\": \"https://latest.datasette.io/fixtures/facetable?_where=_city_id%20in%20(select%20id%20from%20facet_cities%20where%20name%20!=%20%22Detroit%22)\", \"label\": \"facetable?_where=_city_id in (select id from facet_cities where name != \\\"Detroit\\\")\"}, {\"href\": \"https://latest.datasette.io/fixtures/roadside_attractions?_through={%22table%22:%22roadside_attraction_characteristics%22,%22column%22:%22characteristic_id%22,%22value%22:%221%22}\", \"label\": \"an example\"}]"}
{"id": "json_api:json-api-special", "page": "json_api", "ref": "json-api-special", "title": "Special JSON arguments", "content": "Every Datasette endpoint that can return JSON also accepts the following\n query string arguments: \n \n \n ?_shape=SHAPE \n \n The shape of the JSON to return, documented above. \n \n \n \n ?_nl=on \n \n When used with ?_shape=array produces newline-delimited JSON objects. \n \n \n \n ?_json=COLUMN1&_json=COLUMN2 \n \n If any of your SQLite columns contain JSON values, you can use one or more\n _json= parameters to request that those columns be returned as regular\n JSON. Without this argument those columns will be returned as JSON objects\n that have been double-encoded into a JSON string value. \n Compare this query without the argument to this query using the argument \n \n \n \n ?_json_infinity=on \n \n If your data contains infinity or -infinity values, Datasette will replace\n them with None when returning them as JSON. If you pass _json_infinity=1 \n Datasette will instead return them as Infinity or -Infinity which is\n invalid JSON but can be processed by some custom JSON parsers. \n \n \n \n ?_timelimit=MS \n \n Sets a custom time limit for the query in ms. You can use this for optimistic\n queries where you would like Datasette to give up if the query takes too\n long, for example if you want to implement autocomplete search but only if\n it can be executed in less than 10ms. \n \n \n \n ?_ttl=SECONDS \n \n For how many seconds should this response be cached by HTTP proxies? Use\n ?_ttl=0 to disable HTTP caching entirely for this request. \n \n \n \n ?_trace=1 \n \n Turns on tracing for this page: SQL queries executed during the request will\n be gathered and included in the response, either in a new \"_traces\" key\n for JSON responses or at the bottom of the page if the response is in HTML. \n The structure of the data returned here should be considered highly unstable\n and very likely to change. \n Only available if the trace_debug setting is enabled.", "breadcrumbs": "[\"JSON API\"]", "references": "[{\"href\": \"https://fivethirtyeight.datasettes.com/fivethirtyeight.json?sql=select+%27{%22this+is%22%3A+%22a+json+object%22}%27+as+d&_shape=array\", \"label\": \"this query without the argument\"}, {\"href\": \"https://fivethirtyeight.datasettes.com/fivethirtyeight.json?sql=select+%27{%22this+is%22%3A+%22a+json+object%22}%27+as+d&_shape=array&_json=d\", \"label\": \"this query using the argument\"}]"}
{"id": "json_api:json-api-shapes", "page": "json_api", "ref": "json-api-shapes", "title": "Different shapes", "content": "The default JSON representation of data from a SQLite table or custom query\n looks like this: \n {\n \"database\": \"sf-trees\",\n \"table\": \"qSpecies\",\n \"columns\": [\n \"id\",\n \"value\"\n ],\n \"rows\": [\n [\n 1,\n \"Myoporum laetum :: Myoporum\"\n ],\n [\n 2,\n \"Metrosideros excelsa :: New Zealand Xmas Tree\"\n ],\n [\n 3,\n \"Pinus radiata :: Monterey Pine\"\n ]\n ],\n \"truncated\": false,\n \"next\": \"100\",\n \"next_url\": \"http://127.0.0.1:8001/sf-trees-02c8ef1/qSpecies.json?_next=100\",\n \"query_ms\": 1.9571781158447266\n} \n The columns key lists the columns that are being returned, and the rows \n key then returns a list of lists, each one representing a row. The order of the\n values in each row corresponds to the columns. \n The _shape parameter can be used to access alternative formats for the\n rows key which may be more convenient for your application. There are three\n options: \n \n \n ?_shape=arrays - \"rows\" is the default option, shown above \n \n \n ?_shape=objects - \"rows\" is a list of JSON key/value objects \n \n \n ?_shape=array - an JSON array of objects \n \n \n ?_shape=array&_nl=on - a newline-separated list of JSON objects \n \n \n ?_shape=arrayfirst - a flat JSON array containing just the first value from each row \n \n \n ?_shape=object - a JSON object keyed using the primary keys of the rows \n \n \n _shape=objects looks like this: \n {\n \"database\": \"sf-trees\",\n ...\n \"rows\": [\n {\n \"id\": 1,\n \"value\": \"Myoporum laetum :: Myoporum\"\n },\n {\n \"id\": 2,\n \"value\": \"Metrosideros excelsa :: New Zealand Xmas Tree\"\n },\n {\n \"id\": 3,\n \"value\": \"Pinus radiata :: Monterey Pine\"\n }\n ]\n} \n _shape=array looks like this: \n [\n {\n \"id\": 1,\n \"value\": \"Myoporum laetum :: Myoporum\"\n },\n {\n \"id\": 2,\n \"value\": \"Metrosideros excelsa :: New Zealand Xmas Tree\"\n },\n {\n \"id\": 3,\n \"value\": \"Pinus radiata :: Monterey Pine\"\n }\n] \n _shape=array&_nl=on looks like this: \n {\"id\": 1, \"value\": \"Myoporum laetum :: Myoporum\"}\n{\"id\": 2, \"value\": \"Metrosideros excelsa :: New Zealand Xmas Tree\"}\n{\"id\": 3, \"value\": \"Pinus radiata :: Monterey Pine\"} \n _shape=arrayfirst looks like this: \n [1, 2, 3] \n _shape=object looks like this: \n {\n \"1\": {\n \"id\": 1,\n \"value\": \"Myoporum laetum :: Myoporum\"\n },\n \"2\": {\n \"id\": 2,\n \"value\": \"Metrosideros excelsa :: New Zealand Xmas Tree\"\n },\n \"3\": {\n \"id\": 3,\n \"value\": \"Pinus radiata :: Monterey Pine\"\n }\n] \n The object shape is only available for queries against tables - custom SQL\n queries and views do not have an obvious primary key so cannot be returned using\n this format. \n The object keys are always strings. If your table has a compound primary\n key, the object keys will be a comma-separated string.", "breadcrumbs": "[\"JSON API\"]", "references": "[]"}
{"id": "json_api:json-api-pagination", "page": "json_api", "ref": "json-api-pagination", "title": "Pagination", "content": "The default JSON representation includes a \"next_url\" key which can be used to access the next page of results. If that key is null or missing then it means you have reached the final page of results. \n Other representations include pagination information in the link HTTP header. That header will look something like this: \n link: