Kaizen #199: FAQs on Multi-Select Lookup (MxN) Field in Zoho CRM

Kaizen #199: FAQs on Multi-Select Lookup (MxN) Field in Zoho CRM

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Hey everybody!!!
Welcome back to another post in the Kaizen series!
In this post, we will address some of the most frequently asked questions about the Multi-Select Lookup(MxN) field from the Zoho CRM developer community forum.

1. What is a Multi-select lookup field?

A multi-select lookup field in Zoho CRM lets you create a many-to-many relationship between two modules. This means a record in one module can be linked to multiple records in another module and vice versa.
For example, using an multi-select lookup field, you can associate multiple skills with an employee.

2. How does the Mutli-Select Lookup relationship work?

When you create a Multi-Select Lookup between two modules, for example, Employees and Skills, Zoho CRM automatically creates a hidden linking module, which is also known as an MxN module. This module stores the associations between records in the two modules, enabling you to track and manage many-to-many relationships.

For instance, if you link Employees and Skills, a linking module named EmpXSkills will be created.

This linking module is accessible only via API.

Backend Flow of multi-select lookup Relationship



In the linking module, two lookup fields (lookup fields with api names - Employees and Skills) will be created. The lookup fields, one pointing to Employees and the other pointing to Skills from the linking module, establish a connection between the linking module and its associated module.

Why you cannot use a lookup field for this use case? 
In Zoho CRM, a lookup field creates a one-to-many relationship between two modules i.e. one record in the source module can be linked to only one record in the target module.

Example :
If you create a lookup field for Skills in the Employees module, each employee can be linked to only one skill. So, use a multi-select lookup field instead of a lookup field when you need to represent complex relationships like one employee - many skills and one skill - many employees.

3. How to create a multi-select Lookup field using Zoho CRM APIs?

To create a Multi-Select lookup field between two modules using Zoho CRM APIs, follow these steps:

Step 1: Identify the Module API Name
Before creating the field, you should know the API names of the Employees and Skills modules. For that, use the Get Module Metadata API.  

Request URL  : {{api-domain}}/crm/v8/settings/modules
Request method : GET



Now, search for the Employees module in the response and note its API name.

Step 2: Use the Create Custom Fields API

To establish a many-to-many relationship between two modules, in our case, Employees and Skills, you need to create a custom field of type multi-select lookup in the Employees module (parent module).  Here, we will associate multiple skills to an employee.

This custom field requires:
  • The related module you want to link to - Skills.
  • A display field from the related module
  • The linking module (EmpXSkills), which stores the actual associations.
Use the Create Custom Fields API to create custom fields.

Request URL : {{api_domain}}/crm/v8/settings/fields?module=Employees
Request method : POST

Sample input :



{
    "fields": [
        {
            "field_label": "Skills", //Name of the field in your module
            "data_type": "multiselectlookup", //Type of the field
            "multiselectlookup": { //This JSON object contains the multi-select lookup relationship details

                "connected_details": { //Details about the module and field you want to link
                    "module": {
                        "api_name": "Skills" //API name of the related module
                    },
                    "field": {
                        "field_label": "Skills" //The field in the related module to display
                    }
                },
                "linking_details": { //Details about the junction or linking module that manages the many-to-many relationship
                    "module": {
                        "plural_label": "EmpXSkills" //Plural label of the junction module
                    }
                }
            }
        }
    ]
}

4. How Do You Find the Linking Module and Field API Names?

To know the API name of the linking module:
Use the Get Modules API and search for "generated_type" : "linking" in the response to identify MxN modules. In our case, EmpXSkills.

Request URL : {{api_domain}}/crm/v8/settings/modules
Request method : GET



To know the field API names in the linking module:
Use the Get Fields Metadata API to retrieve the API names of lookup fields within the linking module.

Request URL : {{api_domain}}/crm/v8/settings/fields?module=EmpXSkills
Request method : GET

5. How do I associate records via a multi-select lookup field using the Insert Records API in Zoho CRM?

To associate records using a multi-select lookup field, you must provide the record IDs from the related module. The association is made through the linking module.

Example :
Associating multiple skills with an employee using the multi-select lookup field.

Request URL : {{api-domain}}/crm/v8/Employees
Request method : POST

Sample input :


{
  "data": [
    {
      "Name": "Patricia",
      "Email": "patricia@mail.com",
      "Position": "Marketing Specialist",
      "Year_of_Experience": 5,
      "Skills": [   // API name of the multi-select lookup field in the Employees module
        {
          "Skills": { // API name of the lookup field in the linking module pointing to the Skills module
            "name": "Marketing",
            "id": "5725767000002149427"  //ID from the Skills module are mandatory to establish the link
          }
        },
        {
          "Skills": {
            "name": "Social Media Marketing",
            "id": "5725767000002149476"
          }
        }
      ]
    }
  ]
}


6. How do I associate an Employee's skills using the linking module in Zoho CRM?

To establish a relationship between the Employees and Skills modules through the linking module, use the Insert Records API to create a record in the linking module, EmpXSkills.

To do this,
  • Use the appropriate lookup field API names to reference the parent module.
  • You must need the record IDs from both the Employees and Skills modules to create the associations.
Request URL : {{api-domain}}/crm/v8/EmpXSkills
Request method : POST

Sample input :


{
  "data": [
    {
      "Name": "Patricia",
      "Employees": {
        "id": "5725767000002161001"  // Record ID from the Employees module
      },
      "Skills": {
        "id": "5725767000002149476"  // Record ID from the Skills module
      }
    }
  ]
}


7. When should I use create/update operations in the Employees module vs the EmpXSkills module?

                Employees Module

               EmpXSkills (linking) Module

Use when you want to create or update an Employee and associate Skills using the Multi-select Lookup field.

Use when you want to create or remove associations between existing Employee and Skill records without modifying the actual Employee or Skill data.

Creating a new employee and assigning their skills at once.

Managing relationships between existing records i.e., linking and unlinking skills to employees.


8. How to update a record in the linking module?

To update a record in the linking module, use the Update Records API.
Request URL : {{api-domain}}/crm/v8/EmpXSkills/5725767000006269044
Request method : PUT

Sample input :


{
    "data": [
        {
            "Skills": {
                "name": "Marketing",
                "id": "5725767000002170035" //Associating another skill with the employee 
            }
        }
    ]
}
In the above sample, we have replaced an existing skill associated with an employee with another Skill in the linking module.This is done by updating the Skills lookup field in the EmpXSkills record.

Please note that in the linking module, Skills is a lookup field, so you can associate only one skill per linking record. But in the Employees module, Skills is a multi-select lookup field, so an employee can be associated with multiple skills.

9. How to unlink records from the parent module as well as the linking module?

Unlink the associated records from the parent module:

Using the Update records API, you can remove an associated skill from an employee, use the "_delete": null key within the multi-select lookup field in the Employee record update.

Request URL : {{api-domain}}/crm/v8/Employees/5725767000006269044
Request method : PUT

Sample input :

{
"data": [
        {
            "Skills": [
               {
                    "Skills": {
                        "name": "Marketing", 
                        "id": "5725767000002170035" // The Skill record you want to unlink
                    },
                    "id": "5725767000007228047", //record ID - The record created in the linking module for the employee with the Marketing skill
                    "_delete" : null 
                }
            ]
        }
    ]
}

Replace an associated record from the linking module:

Use the Update Records API to replace an existing association in the linking module.

Request URL : {{api-domain}}/crm/v8/EmpXSkills/5725767000007228035
Request method : PUT

Sample input :


{
    "data": [
        {
            "Skills": {
                "name": "Java",
                "id": "5725767000005259075" //replacing a new skill 
            }
        }
    ]
}
In the above sample, we have replaced the existing skill with Java.

10. Why am I seeing the error "DUPLICATE_LINKING_DATA"  in the Update Records API? 

This error occurs when you try to associate records with the parent record that are already linked with the Multi-select lookup field. To resolve this, check the records you are trying to link and make sure your association is only with records that are not already linked.

Know your existing linked records:

Before the Update Records API, use the Get Related Records Data API and search for the multi-select lookup field. In our case, Skills is the multi-select lookup field created in the Employees module. This will return all records already associated.

Example :


The response returns all Skills already linked with that Employee.

Using this way, compare the IDs from the API response with the new records you are about to link, and only proceed with non-duplicate IDs. This avoids duplicate entries and prevents the "DUPLICATE_LINKING_DATA" error.

11. What happens if I delete a record in the linking module?

When you delete a record in the linking module, it only removes the association between the related records in the Employees and Skills modules.

Note :
  • Deleting a linking module record removes only the relationship between two records from the Employees and Skills modules.
  • Deleting an Employee or Skill record deletes all corresponding entries in the linking module as well.

12. How do I query linked records?

Use the COQL API to query multi-select lookup data by specifying the corresponding linking module's API name directly in your query. The linking module is treated as a separate module in Zoho CRM, so you can retrieve associated records by querying it like any other module.

Sample query :


{
  "select_query": "select Skills.Name as skill, Employees.Name as employee from EmpXSkills where Skills.Name like '%Marketing%'"
}

Use the Get Module Metadata API to know the linking module's API name.

13. How do I export multi-select lookup records using the Bulk Read API?

To export multi-select lookup data, linking module records efficiently, use the Bulk Read API with the linking module’s API name.

Request method : POST

Sample Request :


{
    "callback": {
        "method": "post"
    },
    "query": {
        "module": {
            "api_name": "EmpXSkills" //API name of the linking module
        },
        "fields": [
            "Employees.Name",
            "Employees.Year_of_Experience",
            "Skills.Name"
        ],
        "criteria": {
            "group": [
                {
                    "field": {
                        "api_name": "Employees.Year_of_Experience" 
                    },
                    "comparator": "greater_than",
                    "value": "4"
                },
                {
                    "field": {
                        "api_name": "Skills.Name"
                    },
                    "comparator": "contains",
                    "value": "Social"
                }
            ],
            "group_operator": "AND"
        }
    }
}

14. Can I import my linking module's data using the Bulk Write API?

Yes. Like the Leads and Contacts modules, you can also import linking module's data into Zoho CRM using the Bulk Write API by directly specifying the linking module’s API name.

If you are importing data that involves both a parent module, Employees and its associated MxN linking module, follow these steps:

1. Create separate CSV files:
  • One for the parent module - Employees
  • One for the linking module - EmpXSkills
2. Zip the files into a single ZIP file.
3. Upload the ZIP in a single Bulk Write API request.
4. Ensure accurate field mappings are provided in the API request body.

Refer to Kaizen #131 - Bulk Write for parent-child records using Scala SDK for more details on handling parent-child records.


15. Can I receive notifications if a multi-select lookup field in a module is modified or updated?

Yes, you can receive notifications when a MxN field is updated using the Notification API. To enable instant notifications for actions performed in a module, use the respective API names of the linking module in the input body.

Request method : POST

Sample input :


{
    "watch": [
        {
            "channel_id": "10000",
            "events": [
                "EmpXSkills.all"  //EmpXSkills represents the API name of the linking module
            ],
            "return_affected_field_values": true  
        }
    ]
}

16. Can I use criteria-based filtering when accessing multi-select lookup data using the Search API?

Yes, you can filter multi-select lookup data using the criteria parameter in the Search API's URL.

Here is an example that fetches records from the EmpXSkills linking module.

Request URL : {{api-name}}/crm/v8/EmpXSkills/search?criteria=((Secondary_Email:equals:patricia@mail.com)and(Skills:equals:Content_Marketing))
Request method : GET

Sample response :



                                                                                                                               x-----------------------------x


We trust that this post meets your needs and is helpful. Let us know your thoughts in the comment section or reach out to us at support@zohocrm.com 

Stay tuned for more insights in our upcoming Kaizen posts!


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