What are the field datatypes that can be used as external IDs in Salesforce?

Hi,

Auto-number fields can be external IDs. Salesforce.com might be the source of record without explicitly using salesforce.com ID values, which may be case insensitive depending on the other application, which can cause unwanted complications. Using an auto-number field avoids case-sensitive ID values that might otherwise confuse systems not designed to handle such ID values, like Excel (which is, by default, case sensitive).

Hope this helps.

hi,

External ID in salesforce is unique identifier for data used from outside world.Using an auto-number field avoids case-sensitive ID values that might otherwise confuse systems not designed to handle such ID values, like Excel (which is, by default, case sensitive).