id,page,ref,title,content,breadcrumbs,references
facets:facets-in-query-strings,facets,facets-in-query-strings,Facets in query strings,"To turn on faceting for specific columns on a Datasette table view, add one or more  _facet=COLUMN  parameters to the URL.
                For example, if you want to turn on facets for the  city_id  and  state  columns, construct a URL that looks like this: 
             /dbname/tablename?_facet=state&_facet=city_id 
             This works for both the HTML interface and the  .json  view.
                When enabled, facets will cause a  facet_results  block to be added to the JSON output, looking something like this: 
             {
  ""state"": {
    ""name"": ""state"",
    ""results"": [
      {
        ""value"": ""CA"",
        ""label"": ""CA"",
        ""count"": 10,
        ""toggle_url"": ""http://...?_facet=city_id&_facet=state&state=CA"",
        ""selected"": false
      },
      {
        ""value"": ""MI"",
        ""label"": ""MI"",
        ""count"": 4,
        ""toggle_url"": ""http://...?_facet=city_id&_facet=state&state=MI"",
        ""selected"": false
      },
      {
        ""value"": ""MC"",
        ""label"": ""MC"",
        ""count"": 1,
        ""toggle_url"": ""http://...?_facet=city_id&_facet=state&state=MC"",
        ""selected"": false
      }
    ],
    ""truncated"": false
  }
  ""city_id"": {
    ""name"": ""city_id"",
    ""results"": [
      {
        ""value"": 1,
        ""label"": ""San Francisco"",
        ""count"": 6,
        ""toggle_url"": ""http://...?_facet=city_id&_facet=state&city_id=1"",
        ""selected"": false
      },
      {
        ""value"": 2,
        ""label"": ""Los Angeles"",
        ""count"": 4,
        ""toggle_url"": ""http://...?_facet=city_id&_facet=state&city_id=2"",
        ""selected"": false
      },
      {
        ""value"": 3,
        ""label"": ""Detroit"",
        ""count"": 4,
        ""toggle_url"": ""http://...?_facet=city_id&_facet=state&city_id=3"",
        ""selected"": false
      },
      {
        ""value"": 4,
        ""label"": ""Memnonia"",
        ""count"": 1,
        ""toggle_url"": ""http://...?_facet=city_id&_facet=state&city_id=4"",
        ""selected"": false
      }
    ],
    ""truncated"": false
  }
} 
             If Datasette detects that a column is a foreign key, the  ""label""  property will be automatically derived from the detected label column on the referenced table. 
             The default number of facet results returned is 30, controlled by the  default_facet_size  setting.
                You can increase this on an individual page by adding  ?_facet_size=100  to the query string, up to a maximum of  max_returned_rows  (which defaults to 1000).","[""Facets""]",[]
facets:facets-metadata,facets,facets-metadata,Facets in metadata.json,"You can turn facets on by default for specific tables by adding them to a  ""facets""  key in a Datasette  Metadata  file. 
             Here's an example that turns on faceting by default for the  qLegalStatus  column in the  Street_Tree_List  table in the  sf-trees  database: 
             {
  ""databases"": {
    ""sf-trees"": {
      ""tables"": {
        ""Street_Tree_List"": {
          ""facets"": [""qLegalStatus""]
        }
      }
    }
  }
} 
             Facets defined in this way will always be shown in the interface and returned in the API, regardless of the  _facet  arguments passed to the view. 
             You can specify  array  or  date  facets in metadata using JSON objects with a single key of  array  or  date  and a value specifying the column, like this: 
             {
  ""facets"": [
    {""array"": ""tags""},
    {""date"": ""created""}
  ]
} 
             You can change the default facet size (the number of results shown for each facet) for a table using  facet_size : 
             {
  ""databases"": {
    ""sf-trees"": {
      ""tables"": {
        ""Street_Tree_List"": {
          ""facets"": [""qLegalStatus""],
          ""facet_size"": 10
        }
      }
    }
  }
}","[""Facets""]",[]
facets:suggested-facets,facets,suggested-facets,Suggested facets,"Datasette's table UI will suggest facets for the user to apply, based on the following criteria: 
             For the currently filtered data are there any columns which, if applied as a facet... 
             
                 
                     Will return 30 or less unique options 
                 
                 
                     Will return more than one unique option 
                 
                 
                     Will return less unique options than the total number of filtered rows 
                 
                 
                     And the query used to evaluate this criteria can be completed in under 50ms 
                 
             
             That last point is particularly important: Datasette runs a query for every column that is displayed on a page, which could get expensive - so to avoid slow load times it sets a time limit of just 50ms for each of those queries.
                This means suggested facets are unlikely to appear for tables with millions of records in them.","[""Facets""]",[]
facets:id1,facets,id1,Facets,"Datasette facets can be used to add a faceted browse interface to any database table.
            With facets, tables are displayed along with a summary showing the most common values in specified columns.
            These values can be selected to further filter the table. 
         Here's  an example : 
         
         Facets can be specified in two ways: using query string parameters, or in  metadata.json  configuration for the table.",[],"[{""href"": ""https://congress-legislators.datasettes.com/legislators/legislator_terms?_facet=type&_facet=party&_facet=state&_facet_size=10"", ""label"": ""an example""}]"
facets:id2,facets,id2,Facet by JSON array,"If your SQLite installation provides the  json1  extension (you can check using  /-/versions ) Datasette will automatically detect columns that contain JSON arrays of values and offer a faceting interface against those columns. 
             This is useful for modelling things like tags without needing to break them out into a new table. 
             Example here:  latest.datasette.io/fixtures/facetable?_facet_array=tags","[""Facets""]","[{""href"": ""https://latest.datasette.io/fixtures/facetable?_facet_array=tags"", ""label"": ""latest.datasette.io/fixtures/facetable?_facet_array=tags""}]"
facets:id3,facets,id3,Facet by date,"If Datasette finds any columns that contain dates in the first 100 values, it will offer a faceting interface against the dates of those values.
                This works especially well against timestamp values such as  2019-03-01 12:44:00 . 
             Example here:  latest.datasette.io/fixtures/facetable?_facet_date=created","[""Facets""]","[{""href"": ""https://latest.datasette.io/fixtures/facetable?_facet_date=created"", ""label"": ""latest.datasette.io/fixtures/facetable?_facet_date=created""}]"
facets:speeding-up-facets-with-indexes,facets,speeding-up-facets-with-indexes,Speeding up facets with indexes,"The performance of facets can be greatly improved by adding indexes on the columns you wish to facet by.
                Adding indexes can be performed using the  sqlite3  command-line utility. Here's how to add an index on the  state  column in a table called  Food_Trucks : 
             $ sqlite3 mydatabase.db
SQLite version 3.19.3 2017-06-27 16:48:08
Enter "".help"" for usage hints.
sqlite> CREATE INDEX Food_Trucks_state ON Food_Trucks(""state""); 
             Or using the  sqlite-utils  command-line utility: 
             $ sqlite-utils create-index mydatabase.db Food_Trucks state","[""Facets""]","[{""href"": ""https://sqlite-utils.datasette.io/en/stable/cli.html#creating-indexes"", ""label"": ""sqlite-utils""}]"