Use Name for Key in a Map

Question

The below is a valid way to create a Map.

Map<Id, Opportunity> mapOpps = new Map <Id, Opportunity>();

I know that I can use String in place of ID. BUT could someone please explain to me why can't I use Name, as shown?

Map<Name, Opportunity> mapOpps = new Map <Name, Opportunity>();

Answer 1

The Type for this field is String. There is no Type called Name. Note also that the Id Map is the only built in constructor. For any other map, you will need to construct it empty then loop to populate. One more note, this field is not unique. If you have multiple records with the same name, it is arbitrary which one ends up in the map.

Map<String, MyObject> nameToRecord = new Map<String, MyObject>();
for (MyObject record : someCollection)
    nameToRecord.put(record.Name, record);

Answer 2

why can't I use Name, as shown? Map<Name, Opportunity>

Because it’s not a valid data type for the key. Name is a field either text or auto number for any SObject and that only the following are valid data types for a Map’s keys and values:

Map keys and values can be of any data type—primitive types, collections, sObjects, user-defined types, and built-in Apex types.