The importance of record IDs
Why do we have a separate section on record IDs? Once we master them, most of the data operations are a piece of cake. The record ID is a unique identifier of the record. The record ID is similar to the primary ID and foreign ID in a database table.
The Salesforce.com record IDs are not just a bunch of random numbers, but have valuable information that can help us.
18-character and 15-character IDs
Force.com uses two types of IDs, 18 character and 15 character. When we use the ID from the URL it is 15 characters, however, when we use the data loader we get 18 character IDs.
The 15-character ID is case sensitive while the 18 character ID is not case sensitive. The 18-character ID is used to migrate data from legacy systems ...