仅将对主数据库所做的更改复制到设备上的数据库

I am attempting to work on an app where a version of the main database will be stored on the device. However this database would need to be updated with changes made in the main database. Because of the size that this database may be, I would like to look at other options apart from updating the entire database.I am attempting to work on an app where a versi