Couchdb使用密钥连接两个文档 [英] Couchdb join two documents using key
问题描述
我有两个文档,一个是树结构,另一个是第一个doc。我试图通过fk和pk加入这两个doc。我无法获得实际结果并显示所有空值。
I have two documents one with tree structure and the other one relation to the first doc. Im trying to join these two doc`s by fk and pk. I couldnt get the actual results and it displays all null values.
第一个文档
{
"name": "one",
"root": {
"level1" : {
"level2" : {
"level3" : {
"itemone": "Randomkey1",
"itemtwo": "Randomkey2
}
}
}
},
"type": "firstdoc"
}
第二个文档
{
"name" : "two",
"mapBy" : "Randomkey1",
"type" : "senconddoc
}
我写了一个地图函数,其中列出了给出的所有键等级1或2或3。现在我想要使用密钥加入第一个doc和第二个doc。我尝试了两种方式(第一种:我得到所有(Root,Randomkey),(docName,Randomkey1),但它没有做任何连接。我正在寻找像
(Root,docName)
I`ve written a map function, which lists all the keys given a level 1 or 2 or 3 . Now I want o join this first doc and second doc using the key. Ive tried two ways (first: Im getting all (Root, Randomkey), (docName, Randomkey1) but it doesnt do any join. Im looking for a result like (Root, docName)
有人可以协助解决这个问题
Could someone assist in fixing this
地图
function(doc) {
if (doc.type === 'firstdoc' || doc.type === 'seconddoc' ) {
var rootObj = doc.Root;
for (var level1 in rootObj) {
var level2Obj = doc.Root[level1];
for (var level2 in level2Obj) {
var keys = new Array();
var level3Obj = level2Obj[level2];
for (var i in level3Obj) {
var itemObj = level3Obj[i];
for (var i in itemObj) {
keys.push(itemObj[i]);
emit(doc.name, [itemObj[i], 0]);
var firstDocName = doc.name;
//This is gives null values
if (doc.Type === 'senconddoc' && doc.mapBy === itemObj[i]) {
emit(firstDocName , doc);
}
}
}
}
}
}
//This just lists keys to me
if (doc.type === 'senconddoc') {
emit([doc.mapBy, 1] , doc);
}
}
推荐答案
到模拟联接你必须输出一个带有 _id
的文档, _id
的值需要指向一个文件的实际 _id
。然后,您可以使用 include_docs = true
来提取相关文档。这里有多对多的示例: http://danielwertheim.se/couchdb-many -to-many-relations /
To simulate joins you have to output a doc with an _id
in it, the value of the _id
need to point to an actual _id
of a document. Then you can make use of include_docs=true
to pull in the related documents. Example with many-to-many here: http://danielwertheim.se/couchdb-many-to-many-relations/
如果这不适用,您可以通过先返回自定义键进行两步手动连接。然后针对所有文档视图进行第二次查询,并指定多个键。
If this is not applicable, you can make a two step manual join by first returning custom keys. Then make a second query against the all documents view, with multiple keys specified.
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