Standard Fields and Custom Fields in Salesforce

Question

Can someone please let me know what is the difference between Standard Fields and Custom Fields in Salesforce? Can I consider combination of Standard Fields as the unique identifier for a record?

Answer 1

Custom fields are just that. Fields that have been added to the standard Salesforce schema to tailor the data for each object. The user who creates the field can specify the field type and any applicable limitations, such as the maximum number of characters in a text field. These fields might be added to an Org via a managed package or through direct customization.

Standard fields in contrast are those that are already present in the Salesforce schema when a new Organization is created. They are present in all Orgs where the same features are enabled. You can't customize these fields to the same degree. E.g. you could change the display label, but not the underlying API name or data type.

You can see the list of the standard fields in the Salesforce Field Reference Guide

From an API perspective, custom fields are usually identified by a __c suffix (there are a few exceptions, such as GeoLocation fields).

Can I consider a combination of Standard Fields as the unique identifier for a record?

You would usually rely on the Id field to be unique. If you wanted to augment this with another unique value, you would create a custom field and mark it as an External ID.

A composite key isn't directly supported. Instead, you need to create a Unique Text field and then use a workflow field update or before trigger to populate the unique field with the components of the composite key.

I hope it answers your query.