CouchDB索引用于连接文档之间的点

时间:2018-12-12 21:58:09

标签: couchdb pouchdb cloudant couchdb-2.0 couchdb-mango

我有以下文件:

{ _id: "123", type: "project", worksite_id: "worksite_1" }
{ _id: "456", type: "document", project_id: "123" }
{ _id: "789", type: "signature", document_id: "456" }

我的目标是运行查询,并不可避免地对与worksite_id: worksite_1有联系的所有文档进行过滤复制。

示例:

  1. 因为这个项目有我要找的工作地点
  2. 文档中包含该项目
  3. 签名有那个文件

如果我希望从该工作站点获取所有内容,我应该能够检索所有这些文档。

通常,我只需要在worksite_idtype:document中添加一个type:signature。但是,由于各种原因,工作地点可以在项目中更改。

我想知道是否可以创建索引或做一些我不打算显示的相似之处。

This感觉像是在正确的道路上,但说明将文档放在其他文档中,我只希望它们分开。

任何帮助将不胜感激。

2 个答案:

答案 0 :(得分:2)

地图功能一次只考虑一个文档,因此除非该文档了解其他文档,否则无法将它们链接在一起。您的结构意味着用SQL术语进行三表联接。

根据您的结构,您所希望的最好是两个请求的解决方案。您可以创建仅显示签名文档的视图:

function (doc) {
  if (doc && doc.type && doc.type === "signature" && doc.document_id) {
    emit(doc.document_id, {_id: doc.document_id})
  }
}

并使用相同的技术将项目链接到文档-但是您无法将所有三个链接在一起。

答案 1 :(得分:0)

我想我有您要的东西。

以下是一些数据:

{
  "docs": [
    {
        "_id": "123",
        "type": "project",
        "code": "p001"
    },
    {
        "_id": "1234",
        "type": "worksitelog",
        "documents": [
          {
            "timestamp": "20180921091501",
            "project_id": "123",
            "document_id": "457",
            "signature_id": "789"
          },
          {
            "timestamp": "20180921091502",
            "project_id": "123",
            "document_id": "457",
            "signature_id": "791"
          },
          {
            "timestamp": "20180921091502",
            "project_id": "123",
            "document_id": "458",
            "signature_id": "791"
          },
          {
            "timestamp": "20180921091502",
            "project_id": "123",
            "document_id": "456",
            "signature_id": "790"
          }
        ],
        "worksite_id": "worksite_2"
    },
    {
        "_id": "1235",
        "type": "worksitelog",
        "documents": [
          {
            "timestamp": "20180913101502",
            "project_id": "125",
            "document_id": "459",
            "signature_id": "790"
          }
        ],
        "worksite_id": "worksite_1"
    },
    {
        "_id": "124",
        "type": "project",
        "code": "p002"
    },
    {
        "_id": "125",
        "type": "project",
        "code": "p003"
    },
    {
        "_id": "456",
        "type": "document",
        "code": "d001",
        "project_id": "123",
        "worksite_id": "worksite_2"
    },
    {
        "_id": "457",
        "type": "document",
        "code": "d002",
        "project_id": "123",
        "worksite_id": "worksite_2"
    },
    {
        "_id": "458",
        "type": "document",
        "code": "d003",
        "project_id": "123",
        "worksite_id": "worksite_2"
    },
    {
        "_id": "459",
        "type": "document",
        "code": "d001",
        "project_id": "125",
        "worksite_id": "worksite_1"
    },
    {
        "_id": "789",
        "type": "signature",
        "user": "alice",
        "pubkey": "65ab64c64ed64ef41a1bvc7d1b",
        "code": "s001"
    },
    {
        "_id": "790",
        "type": "signature",
        "user": "carol",
        "pubkey": "tlmg90834kmn90845kjndf98734",
        "code": "s002"
    },
    {
        "_id": "791",
        "type": "signature",
        "user": "bob",
        "pubkey": "asdf654asdf6854awer654awer654eqr654wra6354f",
        "code": "s003"
    },
    {
        "_id": "_design/projDocs",
        "views": {
          "docsPerWorkSite": {
            "map": "function (doc) {\n  if (doc.type && ['worksitelog', 'document', 'project', 'signature'].indexOf(doc.type) > -1) {\n    if (doc.type == 'worksitelog') {\n      emit([doc.worksite_id, 0], null);\n      for (var i in doc.documents) {\n        emit([doc.worksite_id, Number(i)+1, 'p'], {_id: doc.documents[i].project_id});\n        emit([doc.worksite_id, Number(i)+1, 'd'], {_id: doc.documents[i].document_id});\n        emit([doc.worksite_id, Number(i)+1, 's'], {_id: doc.documents[i].signature_id});\n      }\n    }\n  }\n}"
          }
        },
        "language": "javascript"
    }
  ]
}

将该数据另存为stackoverflow_53752001.json到磁盘。

使用Fauxton创建一个名为stackoverflow_53752001的数据库。

这是一个bash脚本,用于从文件stackoverflow_53752001.json into the database stackoverflow_53752001`加载数据。显然,您需要编辑前三个参数。对其进行修复,然后将其粘贴到(Unix)终端窗口中:

USRID="you";
USRPWD="yourpwd";
HOST="yourdb.yourpublic.work";

COUCH_DATABASE="stackoverflow_53752001";
FILE="stackoverflow_53752001.json";
#
COUCH_URL="https://${USRID}:${USRPWD}@${HOST}";
FULL_URL="${COUCH_URL}/${COUCH_DATABASE}";
curl -H 'Content-type: application/json' -X POST "${FULL_URL}/_bulk_docs"  -d @${FILE};

在Fauxton中,选择数据库stackoverflow_53752001,然后在左侧菜单中选择“设计文档” >>“ projDocs” >>“视图” >>“ docsPerWorkSite”。

您将看到如下数据:

{"total_rows":17,"offset":0,"rows":[
  {"id":"1235","key":["worksite_1",0],"value":null},
  {"id":"1235","key":["worksite_1",1,"d"],"value":{"_id":"459"}},
          :                     :
          :                     :
  {"id":"1234","key":["worksite_2",4,"p"],"value":{"_id":"123"}},
  {"id":"1234","key":["worksite_2",4,"s"],"value":{"_id":"790"}}
]}

如果您随后单击右上角的“选项”按钮,则将获得用于修改原始查询的选项表。选择:

  • “包含文档”
  • “键之间”
    • “开始键”:[“ worksite_1”,0]
    • “结束键”:[“ worksite_1”,9999]

点击“运行查询”,您应该看到:

{"total_rows":17,"offset":0,"rows":[
  {"id":"1235","key":["worksite_1",0],"value":null,"doc":{"_id":"1235","_rev":"1-de2b919591c70f643ce1005c18da1c54","type":"worksitelog","documents":[{"timestamp":"20180913101502","project_id":"125","document_id":"459","signature_id":"790"}],"worksite_id":"worksite_1"}},
  {"id":"1235","key":["worksite_1",1,"d"],"value":{"_id":"459"},"doc":{"_id":"459","_rev":"1-5422628e475bab0c14e5722a1340f561","type":"document","code":"d001","project_id":"125","worksite_id":"worksite_1"}},
  {"id":"1235","key":["worksite_1",1,"p"],"value":{"_id":"125"},"doc":{"_id":"125","_rev":"1-312dd8a9dd432168d8608b7cd9eb92cd","type":"project","code":"p003"}},
  {"id":"1235","key":["worksite_1",1,"s"],"value":{"_id":"790"},"doc":{"_id":"790","_rev":"1-be018df4ecdf2e6add68a2758b9bd12a","type":"signature","user":"carol","pubkey":"tlmg90834kmn90845kjndf98734","code":"s002"}}
]}

如果随后将开始键和结束键更改为["worksite_2", 0]["worksite_2", 9999],则将看到第二个工作站点的数据。

为此,每次您向数据库中写入新文档和签名时,都需要:

  1. 准备对象{ "timestamp": "20180921091502", "project_id": "123", "document_id": "457", "signature_id": "791" }
  2. 获取相应的工作站点日志记录
  3. 将对象附加到documents数组
  4. 放回更改后的工作站点日志记录

我假设每个文档有多个签名,所以您必须为每个文档编写一个日志记录。我认为,如果该值变得太大,则可以将worksite_id更改为worksite_1_201812之类,这样每个工作站点每个月可以提供一个日志,而不会破坏查询逻辑。