在CouchDB中使用Map-Reduce方法链接文档

Link documents using Map-Reduce approch in CouchDB

本文关键字：方法 链接 文档 Map-Reduce CouchDB      更新时间：2023-09-26
department {
               "_id": "1", 
               "department": "Computers",
               "type": "Department", 
               "room_no": "102", 
               "HOD": "Mr. G Rahul",
               "floor": "1st Floor" 
            }
student {
             "_id": "fdf370e2f43d4af1b505b8913502a5e4",
             "_rev": "1-16df9a4cd45ca69009ab6c9767425a8e",
             "student Name": "H Ravi",
             "date_of_birth": "March 1, 1993",
             "roll_no": "55",
             "inter_marks": "820",
             "secondary_marks": "420"
             "department_id": "1",
             "type": "student"
         }

Map Function

function(doc) {
              var id,department,student,hod,dob;
              if(doc.type == 'student') {
                      id = doc.department_id;
                      dob = new Date(doc.date_of_birth)
                  student = doc;    
              }
             }
       emit(dob, {'_id': id,"student_doc": student});
     }

写完map函数后，我们使用URL "//localhost:5984/db_name/_design/design_name/_view/view_name"调用view。在URL中，我们将添加?include_docs=true在"view_name"("//localhost:5984/db_name/_design/design_name/_view/view_name/?include_docs=true")之后通过在emit中使用_id获取文档，例如:emit(dob，{"_id": id})它将返回链接id的文档…我的问题是如何在reduce函数中访问文档

你不能，文档是在查询时获取的，而不是在索引时，所以reduce函数永远不会看到数据。对不起!

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