What data type is the CreatedById

Question

I am trying to query records (of a custom object) that were created by the current logged in user.

I am trying to use the Created By field to check this. However I can't figure out what the field really is or how to compare it. If I get the record thusly:

SELECT id, Name, CreatedById '+'FROM Reservation__c 

And then display this in a VF page I get a first name last name format with a link. I know that is listed as a lookup field, but is there a way to get the id number?

But on the same page if I use this VF markup:

Hello ID {! $User.Id }

I get an 18 digit user ID.

How can I get a CreatedBy ID that I can compare to the current user ID in Apex code?

Answer 1

CreatedById is an Id field just as Id is, so you can compare the two very simply.

To query records created by the current logged in user:

[SELECT Id, Name, CreatedById FROM Reservation__c WHERE CreatedById = :UserInfo.getUserId()];

--or--

Database.query('SELECT Id, Name, CreatedById FROM Reservation__c WHERE CreatedById = \'' + UserInfo.getUserId() + '\'');

... with all lookup and master-detail fields, the field itself (when queried) is an Id. Salesforce's UI recognizes that it's a reference and instead displays the corresponding record's Name field.

Standard fields toggle the Id demarcation at the end:

Id = CreatedById

Name = CreatedBy.Name

Custom fields toggle the __c for __r at the end:

Id = ParentRecord__c

Name = ParentRecord__r.Name