Salesforce Connect feature support and limitations
Key Takeaway
Salesforce Connect shows outside data in real time through external objects without copying it into the org. Users can edit external object records only after you enable writable external objects on the external data source, because the records are read only by default.
Salesforce Connect lets users view, search, and modify data that stays in an outside system, such as an on-premises ERP. External objects act much like custom objects, but many platform features don't work with them. Knowing which features work, and what the limits are, tells you when Salesforce Connect fits and what to expect after setup.
How external objects work
Salesforce Connect reads external object data on demand, in real time, through web service callouts. The data stays in the outside system, so nothing is copied into the org and nothing goes stale. Performance depends on the outside system.