| ArrayCollection | Class for iterating over a list of Propel objects stored as arrays |
| Collection | Class for iterating over a list of Propel elements The collection keys must be integers - no associative array accepted |
| ObjectCollection | Class for iterating over a list of Propel objects |
| OnDemandCollection | Class for iterating over a statement and returning one Propel object at a time |
| OnDemandIterator | Class for iterating over a statement and returning one Propel object at a time |