set custom field value to other field of same object

Question

I am trying to set the value of one object in a custom object to be the same as the value of another object before deleting the first object. When I use the assignment operator, nothing happens although I'm certain that the Account__r of dbc is populated. Does anybody know why this doesn't work?

for ( Customer__c dbc : [SELECT Account__c, Account__r.Priority__c, Unique_Id__c FROM Customer__c WHERE Unique_Id__c IN :customers.keySet( )])
        {
            Customer__c c    = customers.get( dbc.Unique_Id__c );
            // replace the account of the last added customer if the priority is less
            // than that of the previous entry   
            // I could not find the solution to this problem. I cannot access
            // c.Account__r.Priority__c without using a DB call and could find no solution online.
            if ( accountMap.get( c.Account__c ).Priority__c.compareTo( dbc.Account__r.Priority__c ) 
                 < 0 )
            {
                c.Account__r = dbc.Account__r;
            }
            entriesToBeDeleted.add( dbc );
        }

thanks in advance

Answer 1

Instead of using the c.Account__r, I should have used c.Account__c and I also should have used the c.Account__r.Id rather than c.Account__r.

c.Account__r = dbc.Account__r;

should be

c.Account__c = dbc.Account__r.Id;

maybe someone else is also struggling with this.