What is External ID in Salesforce - The Definitive Guide

In this blog, we will discuss the External ID in Salesforce. So, An External ID is a custom field that has the External ID attribute, which means that it contains unique record identifiers from a system outside of Salesforce. 

The maximum number of external IDs an object may have in Salesforce is around up to 25 External ID fields per object. 

The types of fields which can be used as an external IDs in Salesforce are only custom fields with data type text, numbers, or email as external IDs. 

Don't forget to check out: Classes and Objects in Salesforce | Tutorial Video

Now let’s understand some important points to consider before working with external IDs: 

• An External ID field contains record IDs from systems outside Salesforce. 
• We can only use the upsert call to match against the External ID fields during import or integration in the org. 
• The values in this external ID field must also be unique and we can also determine whether or not values are case-sensitive. 
• Custom fields marked as unique also count against an object limit of external id fields. 
• When a field is marked as external Id, the field will be automatically indexed, so selective filters on them should be run quickly. 

What is the Use of External ID in Salesforce:

• It becomes searchable in the sidebar search. 
• Salesforce record ID is not required to load data. 
• It can be used with UPSERT DML operation to integrate with other systems. 
• The data import wizard detects existing records in Salesforce with external IDs that match those values in the import file. 

Check out another amazing blog by Bhawana here: Subscribe to Dashboards and Reports (Salesforce Lightning Experience)

To Create a Field and Set it as an External ID field: 

Step 1: Go to setup and select Object Manager and then select any object. 

Step 2: Now go to the custom field and relationship section and click New. 

Step 3: In the Data type list, select a data type for the field. 

Step 4: Enter the details for the field and select the field label, length, Field Name, and Description. 

Step 5: Check the External ID box, and click Next. Set the field-level security and then click next and then save. 

The field marked as external ID is created. Now we can use that field as an external ID.