Kaizen #64 - External Fields and Records APIs

Kaizen #64 - External Fields and Records APIs

Hello everyone!
Welcome back to another exciting post in the Kaizen series!
In this post, we will talk about external fields in Zoho CRM and how they are used in Records APIs.

What is an external field?

While you integrate a third-party application, you may want to associate your own primary key in your DB(or an external system) to Zoho CRM's records, and use them in create/update API rather than CRM's "record ID". To meet this requirement, we have introduced external fields.

An external field is a custom single-line field in a module in Zoho CRM that can hold a record's unique ID available in an external system.

This is useful when you want to upsert records to maintain data sync between Zoho CRM and the external system, and also search for records using their external IDs instead of Zoho CRM's record IDs.
External fields negate the need to maintain two unique IDs in your external system.

Types of External Fields

  1. User-based external fields
    User-based external fields allow values to be stored with respect to each user. So, each user can make use of their corresponding external values(say contact1 and contact2) to manipulate CRM records.
    When data sync happens between the external system and Zoho CRM, these users can update the corresponding record with their respective external values(contact1 and contact2). For example, consider that two users have saved the same contact with different IDs c1 and c2, respectively in their external systems. When data sync happens with Zoho CRM from these systems, there will be one contact in CRM. But, the users can use their external contact IDs c1 and c2 to update the record in CRM.
    Note that the external value for this type is unique to each user.
  2. Org-based external fields
    In contrast to user-based external field, for org-based external fields, there is no association between the external ID stored and the user who configured it. Instead, all users can manipulate the CRM records with that same external ID. Consider that you have a native ERP system to manage finances for your org. The employees(users) will deal with the same clients(leads or contacts). When you integrate this external system with Zoho CRM, the lead/contact ID in the external system becomes the external field value in CRM. Now this integration can use this external ID for any data sync and other actions with Zoho CRM.

How to create an external field in CRM?

  1. Go to Setup > Customization > Modules and Fields > Choose a module.
  2. Create a single line field and provide a name.
  3. Click the more options icon and select Edit Properties.
  4. In the Single Line Properties pop up, specify the field label, and check the Set External Field box.
  5. Choose the field's visibility and the type of the external field.


  6. Click Done. Click Save and Close in the module builder.

Note
  • The external ID feature is available only from the Enterprise edition and up.
  • You can create a single line field of the type "external" only through the UI.
  • A module can have a maximum of 10 external fields for the Enterprise edition and 15 for the Ultimate edition.

In this post, we will discuss using external ID fields in create, update, upsert, delete, and search records APIs.

Mandatory Header in the API Requests

X-EXTERNAL: {module_API_name}.{external_field_API_name}

Note that this header is required only when there are references like lookup fields, line items in the inventory modules, subforms, but not when inserting records directly. 

Here is an example of creating a contact while adding a value to the external field.

Module: Contacts
External field's API name: External_Contact_ID, Value: externalcontact1
Input body:

{
    "data": [
        {
            "Last_Name": "ext contact 1",
            "External_Contact_ID":"externalcontact1"
        }
    ]
}

Creating records using external values

Associating a lookup record through an external field

Base Module: Contacts
Lookup Module: Accounts
Lookup field's API name in base module: Account_Name
External field's API name in the lookup module: External_Account_ID; Value: externalaccount1 
Header: X-EXTERNAL: Contacts.Account_Name.External_Account_ID 
Input body:

{
    "data": [
        {
            "Last_Name": "ext contact 2",
            "Account_Name": {
                "External_Account_ID": "externalaccount1"
            }
        }
    ]
}


Inserting a subform lookup record through an external field in the associated module

Base Module: Contacts
API name of the subform in the base module: ExternalSubform
API name of the lookup field in the subform: Deal_Lookup
API name of the external field in the lookup module: External_Deal_ID
Header: X-EXTERNAL: Contacts.ExternalSubform.Deal_Lookup.External_Deal_ID
Input body:


{
    "data": [
        {
            "Last_Name": "Contact with a Subform and external Deal lookup",
            "ExternalSubform": [
                {
                    "Deal_Lookup": {
                        "External_Deal_ID": "extDeal1"
                    }
                }
            ]
        }
    ]
}


Creating an inventory module's record with external fields in the line items

You can create a record in the inventory module by using the external fields and their values in the line items. For example, creating a quote using the external values of the product and the price book in the Quoted_Items line item.

Inventory Module: Quotes
External field's API name in Products: External_Product_ID; Value: extprod1
External field's API name in Price_Books: External_Price_Book_ID; Value: extpricebook1
Header: X-EXTERNAL: Quotes.Quoted_Items.Product_Name.External_Product_ID,Quotes.Quoted_Items.Price_Book_Name.External_Price_Book_ID

Input body:


{
    "data": [
        {
            "Subject": "Quote 1",
            "Quoted_Items": [
                {
                    "Product_Name": {
                        "External_Product_ID": "extprod1"
                    },
                    "Price_Book": {
                        "External_Price_book_ID": "extpricebook1"
                    },
                    "quantity": 100
                }
            ]
        }
    ]
}


Inserting an Event and associating the What_Id through an external field

When you insert an event related to an account, the What_Id takes the name of the account(Account_Name). We can use the external field's value in the Accounts module, instead of the account name while inserting an event.

Base Module: Events
External field's API name in Accounts: External_Account_ID; Value: extAccount1
Header: X-EXTERNAL: Events.What_Id->Accounts.External_Account_ID
Input body:

{
    "data": [
        {
            "se_module": "Accounts",
            "What_Id": {
                "External_Account_ID": "externalaccount1"
            },
            "Event_Title": "Event Kaizen",
            "Start_DateTime": "2023-01-01T10:10:10+05:30",
            "End_DateTime": "2023-01-01T11:10:10+05:30"
        }
    ]
}

You can also add participants(Leads or Contacts) to an event through their external IDs. Here is an example.
Header: X-EXTERNAL : Events.What_Id->Accounts.External_Account_ID,Events.Participants.participant->Contacts.External_Contact_ID


{
    "data": [
        {
            "Participants": [
                {
                    "type": "contact",
                    "participant": {
                        "External_Contact_ID": "extenalcontact3"
                    }
                }
            ],
            "What_Id": {
                "External_Account_ID": "externalaccount1"
            },
            "$se_module": "Accounts",
            "Event_Title": "Kaizen 1",
            "Start_DateTime": "2023-05-10T10:10:10+05:30",
            "End_DateTime": "2023-05-10T11:10:10+05:30"
        }
    ]
}


Note
You can use the same logic for updating records in Zoho CRM through external fields.

Upserting records using external values

Normally, in an upsert API call, the system checks for duplicates based on the system-defined duplicate check fields and user-defined duplicate check fields.

While upserting through external fields, the system considers the external field as a system-defined unique field, checks for the following:
  • If the external value is unique and the other duplicate checks are done, the system inserts the record if no matching record is found.
  • If the external value already exists in a record, the system updates the other fields given in the input to the matching record.
  • If the external value does not exist, the system checks for the system-defined and user-defined duplicate check fields. If a match is found, the system updates the record with the new external value along with other fields in the input.

How upsert works for org-based and user-based external fields?
  • Org-based external fields
    Consider that a user inserts a record using the external value. Now, when another user tries to create a record with the same external value as the previous user's, the system throws the DUPLICATE_DATA error.
  • User-based external fields
    Consider that a user creates a record with an external value. When the same user upserts using the same external value, the system updates the record.

Note that you need not pass the X-EXTERNAL header for upsert operation as the system considers external field to be unique, anyway, and performs duplicate check.

Deleting records using external fields

You can use the external field's value in the request URL and in the "ids" parameter, instead of CRM's record ID.

Here are the sample requests:

Header: X-EXTERNAL: Contacts.External_Contact_ID

Header: X-EXTERNAL: Contacts.External_Contact_ID
  1. https://www.zohoapis.com/crm/v3/Contacts?ids=extcontact3,extcontact4

Searching for records in a module using external values

You can use the external field's API name and its value in the "criteria" parameter of the search Records API.
The supported operators are "equals" and "in".
Here are the sample requests:

Header: X-EXTERNAL: Contacts.External_Contact_ID
  1. https://www.zohoapis.com/crm/v3/Contacts/search?criteria=(External_Contact_ID:in:usercontact2,usercontact123)&fields=External_Contact_ID,Email

Header: X-EXTERNAL: Contacts.External_Contact_ID
  1. https://www.zohoapis.com/crm/v3/Contacts/search?criteria=(External_Contact_ID:equals:usercontact2)&fields=External_Contact_ID,Email


We hope you found this post useful. Let us know your questions in the comment section or write to us at support@zohocrm.com.

Cheers!
Shylaja


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