Unable to pass Dynamic parameter value to a map function in CouchDB

[PreethiVuchuru27916]

Description

I want to pass a dynamic parameter value to the Couchdb map function. But it is failing when additional parameters except doc are passed. Please specify If there is a way to pass a dynamic value to the map function parameter in CouchDB to do some processing inside the function.

Steps to Reproduce

[1] Create a design document and Create a view
[2] Add the following code to the map function.

function (doc, employees) {//where employees is a array inside a document
  if (doc[employees] && Array.isArray(doc[employees])) {
    result = [];
    doc[employees].forEach(function (employee) {
      result.push(employee.empId);
    });
    emit("empIds", result);
  }
}

curl "http://admin:adminpw@localhost:5984/ri-prototype/_design/OrganizationInfo/_view/GetEmployees?employees=\"employees"\""

Expected Behaviour

To pass the employees variable to the view as a parameter.
NOTE: # ( Tell us what you expected to happen. )
I wanted to have dynamic value to be passed to the map function of a view in CouchDB.

Your Environment

• CouchDB version used: CouchDB v. 3.2.2
• Browser name and version: Safari Version 15.3
• Operating system and version: Mac OS

Additional Context

[big-r81]

Hi Preethi,

this will not work! You cannot change the method signature.

Ich vermutet, du möchtest dir alle Angestellten auflisten lassen. Dazu könntest du zum Beispiel in deinen Datensätzen ein Attribute type mit dem Wert employee einfügen, z.Bsp.:

{
  "_id": ".....",
  "firstName": "Preethi",
  "lastName": "Vuchuru",
  "address": "...",
  "type": "employee"
}

If you now want to list all employees, you could use this map function (only an example:

function(doc) {
    if (doc.type == "employee") {
        emit(doc.LastName, {FirstName: doc.firstName, Address: doc.address});
    }
}

This will emit something like this, if you call your view:

$db/_design/OrganizationInfo/_view/GetEmployees

{"id":"doc2","key":"Vuchuru","value":{"FirstName":"Preethi","Address":"..."}}

This would show you all of your employees order by their last name in ascending order.

You can read more about views in our docs, e.g. https://docs.couchdb.org/en/stable/ddocs/views/index.html

[PreethiVuchuru27916]

Thanks Ronny! Is there any way I can pass a dynamic value to be validated against the if condition?
Is there any notation where I don't have to specify the employee as a hard coded value? For example,

function(doc) {
    if (doc.type == DYNAMIC_VALUE) { // rather than if (doc.type == "employee") {
        emit(doc.LastName, {FirstName: doc.firstName, Address: doc.address});
    }
}

So the above function can create a view based on the dynamic value set somewhere. If the dynamic value passed is employee, then it will construct a employee view with key and value pairs. If the dynamic value passed is company, then it will construct a company view with key and value pairs. Can you please confirm if this dynamic nature is possible in a view or if the views needs to be constructed with prior planning and hardcoding in a view is considered normal?

[big-r81]

Hi Preethi,

no this is not possible. You can create multiple design documents or you can create multiple views within one design document. So you can construct a view for a company and a view for employees. I don't think it's a good idea to mix those in one ddoc, because they have different data in it.

An other way to do a "dynamic" query is to use the GET parameter startkeyand endkey in combination with include_docs. You can look at our docs for more infos and examples.

But I'm only guessing at the moment, so can you explain to me what exactly you want to do?

[PreethiVuchuru27916]

I have the following document inside couchdb. Now I want to retrieve value for batters.batter.id == 1003 when the type specified by the user is batters. And I want to retrieve value for toppings.id == 5001 when the type specified by the user is topping. Can this be possible without using index in the query? Point to be noted is that : the json structure can be nested as much as possible and still the dynamic query needs to be constructed.

{
  "items":{
    "item":[
      {
        "id":"0001",
        "batters":{
          "batter":[
            {
              "id":"1003",
              "type":"Blueberry"
            },
            {
              "id":"1004",
              "type":"Devil's Food"
            }
          ]
        },
        "topping":[
          {
            "id":"5001",
            "type":"None"
          },
          {
            "id":"5002",
            "type":"Glazed"
          }
        ]
      }
    ]
  }
}

[big-r81]

So if you "search" for batters, you want to get Blueberry as result and if you search for topping you want to get None as result or do I understand this wrong? Can you give an example result or a more detailed example?