How salesforce compares on sObject with another

Question

We know that "Set" is a collection of unique records. If I am creating a set of SObjects, on what basis Salesforce identifies Uniqueness of the entries in the Set?

Answer 1

It depends on the fields and their values being added for that SObject.

Refer to Sets of Objects for details:

Uniqueness of sObjects is determined by comparing the objects’ fields. For example, if you try to add two accounts with the same name to a set, with no other fields set, only one sObject is added to the set.

Sample code from the link:

// Create two accounts, a1 and a2
Account a1 = new account(name='MyAccount');
Account a2 = new account(name='MyAccount');

// Add both accounts to the new set 
Set<Account> accountSet = new Set<Account>{a1, a2};

// Verify that the set only contains one item
System.assertEquals(accountSet.size(), 1);