External ID in Salesforce

The unique identifiers from external systems, such as an ERP, marketing automation platform, or another CRM, are stored in custom or standard fields in Salesforce called External IDs.

They link Salesforce records and the corresponding records in various other systems, allowing for effective synchronization and data interchange.

Let’s understand this feature in depth.

What is External ID in Salesforce?

External ID in Salesforce is any custom field with the “External ID” attribute checked, meaning it contains unique record identifiers from a system outside of Salesforce.

This operation is case-insensitive, but if the custom field has a separate “Unique” attribute, then the case-sensitive option for that field is selected, meaning Uppercase and Lowercase letters will not be considered identical. For example, “Abc” and “abc” will be treated differently. 

An object can have at most 25 external IDs and Unique fields. Custom fields marked as unique also count against an object’s 25 external ID fields limit.

The external ID field type can only be any auto number, email, number, or text. When we select this option, the import wizard will detect existing Salesforce records with the exact external identification.

Note: We should choose both “Unique” and “ExternalId” attributes, but it is not mandatory to choose the required attribute to make the field accessible on the data import wizard.

Key Features of External ID

• Purpose: Link Salesforce records to corresponding records in external systems.
• Field Type: Custom text, number, or email fields designated “External ID.”
• Uniqueness: This can be set as “Unique” to ensure no duplicate values within the field.

Benefits of External ID

• Efficient data import and synchronization from external systems.
• Improved data accuracy and consistency across platforms.
• Easier record identification and reference using external identifiers.
• Faster retrieval of related data from external systems.

Use Cases

• Importing customer data from an ERP system.
• Integrating Salesforce with marketing automation campaigns.
• Connecting with other CRMs for lead handoff or data exchange.
• Synchronizing product information with an e-commerce platform.

Field Types Supported as External ID in Salesforce

You can mark some field types in Salesforce as “External ID.” This makes it possible for these fields to store distinct IDs from outside systems and quickly link related data. The supported field types are as follows:

Text: If the values in a basic text field are distinct and match the identifiers of the external system, they can function as an External ID.

Number: To retain uniqueness, numerical fields that contain no fractions or decimals should not be used as External IDs.

Email: If every record in your Salesforce database and external system has a distinct email address, then the email address field can serve as an External ID.

Auto Number: This sequence number is generated by the system and can serve as a unique identification. It increases automatically with each new entry.

Text Encrypted: This text field encrypts values for additional security when handling sensitive external identifiers.

Difference Between “Unique ID” and External ID in Salesforce:

While both concepts seem similar, they serve distinct purposes:

Unique ID

• This isn’t a field type; this is a setting.
• It promotes data integrity in your Salesforce instance by ensuring no two records in the same field have the same value.
• Any supported field type can be marked as “Unique,” even if it isn’t marked as “External ID.”
• It only pertains to Salesforce’s internal data consistency; external system connection is not covered.

External ID

• As was previously said, this is a specified field type.
• Specifically, it uses unique identifiers from those systems to link Salesforce entries to their equivalents in external systems.
• Salesforce allows “External ID” fields to be set to “Unique,” although this setting mainly affects relationships with external data.

Feature	Unique ID	External ID
Purpose	Internal data consistency	Linking to external systems
Applies to	Any supported field type	Designated field types
Focus	Maintaining internal data integrity	Facilitating data exchange

Understanding these differences is crucial for choosing the appropriate field type and setting for your data management needs in Salesforce.

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