id,page,ref,title,content,breadcrumbs,references
json_api:json-api-pagination,json_api,json-api-pagination,Pagination,"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. 
             Other representations include pagination information in the  link  HTTP header. That header will look something like this: 
             link: <https://latest.datasette.io/fixtures/sortable.json?_next=d%2Cv>; rel=""next"" 
             Here is an example Python function built using  requests  that returns a list of all of the paginated items from one of these API endpoints: 
             def paginate(url):
    items = []
    while url:
        response = requests.get(url)
        try:
            url = response.links.get(""next"").get(""url"")
        except AttributeError:
            url = None
        items.extend(response.json())
    return items","[""JSON API""]","[{""href"": ""https://requests.readthedocs.io/"", ""label"": ""requests""}]"
sql_queries:id2,sql_queries,id2,Pagination,"Datasette's default table pagination is designed to be extremely efficient. SQL OFFSET/LIMIT pagination can have a significant performance penalty once you get into multiple thousands of rows, as each page still requires the database to scan through every preceding row to find the correct offset. 
             When paginating through tables, Datasette instead orders the rows in the table by their primary key and performs a WHERE clause against the last seen primary key for the previous page. For example: 
             select rowid, * from Tree_List where rowid > 200 order by rowid limit 101 
             This represents page three for this particular table, with a page size of 100. 
             Note that we request 101 items in the limit clause rather than 100. This allows us to detect if we are on the last page of the results: if the query returns less than 101 rows we know we have reached the end of the pagination set. Datasette will only return the first 100 rows - the 101st is used purely to detect if there should be another page. 
             Since the where clause acts against the index on the primary key, the query is extremely fast even for records that are a long way into the overall pagination set.","[""Running SQL queries""]",[]