PostgreSQL 9.2中将引入生成JSON数据功能
fmms 13年前
PostgreSQL开发者Andrew Dunstan <a href="/misc/goto?guid=4958326103248420108" target="_blank">写到</a>： <br /> <div class="quote_title"> 引用 </div> <div class="quote_div"> 上周三，也就是PostgreSQL 9.2最后一个 <a href="/misc/goto?guid=4958326104059031135" target="_blank">commitfest</a>到来的前四天，Robert Haas提交了一个名为 <a href="/misc/goto?guid=4958326104854642107" target="_blank">JSON for 9.2</a>的补丁，欲将JSON列为PostgreSQL的核心类型。基本上，该补丁功能是对文本进行解析，确保它是有效的JSON数据，并加以存储。这个功能我原本打算在9.2版本中放弃的，不过我考虑了下发现Robert的补丁太小了点，因此决定继续并又添加了一些功能，包括：query_to_json()、 array_to_json()以及record_to_json()，完成了从ProstgreSQL生成JSON数据。 </div> <br /> 以下是来自回归测试中的一些简单示例： <pre class="brush:sql; toolbar: true; auto-links: false;">SELECT query_to_json('select x as b, x * 2 as c from generate_series(1,3) x',false); query_to_json --------------------------------------------- [{"b":1,"c":2},{"b":2,"c":4},{"b":3,"c":6}] (1 row) SELECT array_to_json('{{1,5},{99,100}}'::int[]); array_to_json ------------------ [[1,5],[99,100]] (1 row) -- row_to_json SELECT row_to_json(row(1,'foo')); row_to_json --------------------- {"f1":1,"f2":"foo"} (1 row)</pre>更简单一点的： <pre class="brush:sql; toolbar: true; auto-links: false;">SELECT row_to_json(q) FROM (SELECT $$a$$ || x AS b, y AS c, ARRAY[ROW(x.*,ARRAY[1,2,3]), ROW(y.*,ARRAY[4,5,6])] AS z FROM generate_series(1,2) x, generate_series(4,5) y) q; row_to_json -------------------------------------------------------------------- {"b":"a1","c":4,"z":[{"f1":1,"f2":[1,2,3]},{"f1":4,"f2":[4,5,6]}]} {"b":"a1","c":5,"z":[{"f1":1,"f2":[1,2,3]},{"f1":5,"f2":[4,5,6]}]} {"b":"a2","c":4,"z":[{"f1":2,"f2":[1,2,3]},{"f1":4,"f2":[4,5,6]}]} {"b":"a2","c":5,"z":[{"f1":2,"f2":[1,2,3]},{"f1":5,"f2":[4,5,6]}]} (4 rows)</pre>Via <a href="/misc/goto?guid=4958326103248420108" target="_blank">planetpostgresql</a> <br /> 来自： <a href="/misc/goto?guid=4958326106375777161" target="_blank">http://www.iteye.com/news/24032</a>