Table of Contents:

• What is a Multi-Module Lookup (MML) Field in Zoho CRM?
• Use Cases for MML
  
• How  the "Appointment For" (MML) field in the "Appointments" module works?
• Creating a Record in the Appointments Module Using the Insert Records API
• Retrieving a Record from the Appointments Module Using the Get Records API
• Multi-module Lookup Using the COQL API
• Multi-module Lookup Using the Bulk Read API
• Frequently Asked Questions
  

What is a Multi-Module Lookup (MML) Field in Zoho CRM?

A Multi-Module Lookup (MML) field in Zoho CRM allows you to create a one-to-one relationship between a record in one module and a record from one of multiple other modules. Unlike a normal lookup field, which references a single module, an MML field can dynamically reference records from multiple modules. 

Without the MML field, users must create multiple lookup fields for each module, which complicates the CRM layout and user experience.

Note:

• The multi-module lookup (multi_module_lookup) data type was introduced in Zoho CRM API version 3.
• Currently, the MML field is available as a system-defined field named Appointment For in the Appointments module. 
• The Appointment For field supports lookups to both Contacts and custom modules.
• You cannot create a custom MML field in Zoho CRM.

Data Model Representation

MML's Data Model Representation

Use Cases for MML

Zylker Healthcare is a multi-specialty hospital that uses Zoho CRM to maintain its appointment scheduling process. 

In this setup, Zylker maintains two key modules:

• Contacts module - Stores records of physicians and surgeons, including attending physicians, specialists, and surgeons who diagnose and refer patients.
• Patients module - A custom module used to maintain records of all patients.

To improve the appointment booking process, Zylker uses the "Appointment For" Multi-Module Lookup (MML) field in the Appointments module. This field lets Zylker manage an appointment with either a Physician/Surgeon or a Patient, eliminating the need for multiple lookup fields.

• When creating an appointment, the user selects the "Appointment For" field.
• The field displays records based on the selected module, either the Contacts or  Patients. 
• The user selects the appropriate record (Contact or Patients) for the appointment.
• A related list is automatically created in the selected module (Contact or Patients) as the Open Activities / Closed Activities to display all appointments associated with that record.
  

Creating a Record in the Appointments module using the Insert Records API

System-defined mandatory keys in the Appointments Module in UI view.

API calls you have to make before creating a record:

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

Request Method : GET

Sample Response :

 

In the API response, search for the module with "module_name": "Appointments" and check the value of the "api_name" key to get the API name of the module. This is the name you will use in all related API calls.

ii. Use the GET - Fields Metadata API and get fields metadata for the Appointments module. Here, you can find the API names of the mandatory fields along with other fields present in the Appointments module. 

Below is the API call & response for the multi-module lookup field along with other mandatory fields.

Request URL : {api-domain}/crm/v8/settings/fields?module=Appointments__s

Request Method : GET

Sample Response :

• The multi-module lookup field is identified by the key "data_type" with the value "multi_module_lookup".
• The associated modules supported by the MML field (e.g., Contacts, Patients) are listed under the "modules" key.
• Other mandatory fields like Service Name, Appointment Name, and Appointment Start Time can be identified by "system_mandatory": true.
  

Frequently Asked Questions

1. Which modules are currently supported in the MML field?

2. What error is thrown if I try to associate a record with a removed or unsupported module in the MML field?

3. Is the MML field available for all modules?

4. How do I get the list of modules associated with an MML field?

5. Can I add or remove modules from a Multi-Module Lookup (MML) field via API?

6. What happens if I remove a module from an MML field?

7. Is MML field supported in the Bulk Write API?

8. Is MML field supported in the Search API?