相关疑难解决方法(0)

我正在尝试测试jsonPostgreSQL 9.3中的类型.
我在一个json名为data的表中调用了一列reports.JSON看起来像这样:

{
  "objects": [
    {"src":"foo.png"},
    {"src":"bar.png"}
  ],
  "background":"background.png"
}

我想查询表中所有与'objects'数组中'src'值匹配的报告.例如,是否可以在数据库中查询匹配的所有报告'src' = 'foo.png'？我成功写了一个可以匹配的查询"background":

SELECT data AS data FROM reports where data->>'background' = 'background.png'

但由于"objects"有一系列的价值观,我似乎无法写出有用的东西.是否可以在数据库中查询匹配的所有报告'src' = 'foo.png'？我查看了这些来源,但仍然无法得到它:

• http://www.postgresql.org/docs/9.3/static/functions-json.html
• 如何使用新的PostgreSQL JSON数据类型中的字段进行查询？
• http://michael.otacoo.com/postgresql-2/postgres-9-3-feature-highlight-json-operators/

我也尝试过这样的事情,但无济于事:

SELECT json_array_elements(data->'objects') AS data from reports
WHERE  data->>'src' = 'foo.png';

我不是SQL专家,所以我不知道我做错了什么.

我有一个看起来像这样的表:

CREATE TABLE tracks (id SERIAL, artists JSON);

INSERT INTO tracks (id, artists) 
  VALUES (1, '[{"name": "blink-182"}]');

INSERT INTO tracks (id, artists) 
  VALUES (2, '[{"name": "The Dirty Heads"}, {"name": "Louis Richards"}]');

还有其他几个与此问题无关的列.将它们存储为JSON是有原因的.

我要做的是查找具有特定艺术家姓名(完全匹配)的曲目.

我正在使用此查询:

SELECT * FROM tracks 
  WHERE 'ARTIST NAME' IN
    (SELECT value->>'name' FROM json_array_elements(artists))

例如

SELECT * FROM tracks
  WHERE 'The Dirty Heads' IN 
    (SELECT value->>'name' FROM json_array_elements(artists))

但是,这会进行全表扫描,并且速度不是很快.我尝试使用函数创建GIN索引names_as_array(artists)并使用'ARTIST NAME' = ANY names_as_array(artists),但是不使用索引并且查询实际上明显更慢.

我的功能是:

 CREATE OR REPLACE FUNCTION FnUpdateSalegtab09
(
 iacyrid Integer,iRepId Integer,iDrId Integer,ivrid Integer,imode smallint,itrno 
varchar,itrdate timestamp,iacid Integer,ivrno varchar,iSuppId Integer,icustname 
varchar,inetamt money,idisrate real,idisamt money,iRoundOff real,ijrmid integer,iuserid 
integer,iuserdtm timestamp,iVSNo integer,iRecdAmt money,icstrate real,icstsaleamt 
money,icstamt money,itdrate real,itdamt money,icdrate real,icdamt money,iCessRate 
real,iCessAmt money,iodesc1 varchar,ioamt1 money,iCashCredit boolean,iOrderNo 
varchar,iOrderDate timestamp,iCustAdd2 varchar,iRemarks varchar,iWhoRetSl boolean,iPatName 
varchar,iDrName varchar,iFormId integer,iSalesMan varchar,iCFMode smallint,iPatId 
integer,iStkPtId integer,iDisType smallint,iBranchID integer
)
RETURNS void AS
'BEGIN 
INSERT INTO gtab09 
(
acyrid, RepId, DrId, vrid, mode, trno, trdate, acid, vrno, SuppId, custname, netamt,
disrate, disamt, RoundOff, jrmid, userid, …

这个psql会话片段应该是不言自明的:

psql (9.1.7)
Type "help" for help.
=> CREATE TABLE languages(language VARCHAR NOT NULL);
CREATE TABLE
=> INSERT INTO languages VALUES ('english'),('french'),('turkish');
INSERT 0 3
=> SELECT language, to_tsvector('english', 'hello world') FROM languages;
 language|     to_tsvector     
---------+---------------------
 english | 'hello':1 'world':2
 french  | 'hello':1 'world':2
 turkish | 'hello':1 'world':2
(3 rows)

=> SELECT language, to_tsvector(language, 'hello world') FROM languages;
ERROR:  function to_tsvector(character varying, unknown) does not exist
LINE 1: select language, to_tsvector(language, 'hello world')...
                         ^
HINT:  No function matches the given …