windows or linux. to build for speciﬁc devices, you have to have the device SDK installed. in other words, you must have xcode, and therefore mac os x, installed for an iphone build targeted towards enterprise apps. what’s that mean? its not good for games or graphic intensive apps or platform-speciﬁc native UI controls. if you were planning to build the next angry birds, you can leave now.
• “An Application may not itself install or launch other executable code by any means, including without limitation through the use of a plug-in architecture, calling other frameworks, other APIs or otherwise. No interpreted code may be downloaded and used in an Application except for code that is interpreted and run by Apple’s Published APIs and built-in interpreter(s).” (www.rhomobile.com/blog/2009/05/29/iphone-app-store- rules-and-guidelines-on-use-of-frameworks/) Tuesday, February 5, 13
it doesn’t require specifying attributes. • Data migrations are not necessary. • Attributes can be added or removed without modifying the database schema. Cons: • db size: For some applications, the database size may be significantly larger than fixed schema. This is because each attribute is indexed for fast lookup. • slower Sync: process may be slightly slower because inserts are performed at attribute level.
Advantages • Smaller database size, indexes can be specified only on specific attributes. • Sync process may perform faster because whole objects are inserted at a time. Fixed Schema Disadvantages • Schema changes must be handled with data migrations. • Database performance may be slow unless you specify proper indexes. When the application starts the first time after an update, the database will be (re)created if theapp_db_version in rhoconfig.txt is different from what existed before. If the database is recreated, the existing database is removed along with all data. on_migrate_source(old_version, new_src)
• paginate • ﬁnd(*args) (:all, :ﬁrst, :count, :conditions, :order, :orderdir, :select, :per_page, :offset) • ﬁnd_by_sql <-- only for ﬁxed schema Tuesday, February 5, 13 ﬁnd_by_sql is SLOW! only works for ﬁxed schema