将iOS核心数据导入android sqlite

Question

I want to share data between my android and iOS apps. I've exported core data sqlite from this directory, ~/Library/Application Support/iPhone Simulator/User/Applications//Documents/.sqlite

Which is fine I think. The problem arises when I've try to open the sqlite file with sqlite browser. As it gives an error, "Not a sqlite 3 file". I was thinking that I will import that coredata sqlite file into android.

However my question is, What is the proper way to import iOS coredata into android sqlite?

Answer 1

There's no really good way to take a SQLite file created by Core Data and use it anywhere else. Core Data is more than just a SQLite wrapper, it provides a rather different API with different rules and assumptions (for example, Core Data has true many-to-many relationships, so you don't need to create join tables). SQLite is an implementation detail. As a result, the schema in one of these SQLite files has only a passing resemblance to the Core Data object model. You could open the SQLite file anywhere, but making sense of it might be a problem.

If you want to use the same data and you're already using Core Data, you'll need to have your app export the data to something more portable-- CSV maybe, or a more generic SQLite file, or anything else that looks good to you.

If you're not already using Core Data and you need this portability, you might be better off using SQLite directly with whatever schema you need. You don't have to go through Core Data to use SQLite on iOS if it's not what you need. You can either use SQLite's API directly or else go via wrappers like PLDatabase or FMDB .

Answer 2

Core Data's SQLite store is a vanilla SQLite file, so something else is going wrong with your import. However the mapping that Core Data makes from its entities to the SQLite store is explicitly implementation dependent and, as a result, is not part of the specification and is therefore not documented. As it is allowed to change between versions of Core Data it's also not necessarily safe to reverse engineer it*.

As of iOS 5, if you really want to use Core Data and SQLite then what you can do is write your own NSIncrementalStore . That'll allow you to impose any mapping from Core Data to SQLite that you desire. The downside is that it's barely documented.

(*) although it is sometimes helpful to poke around in there; you can supply the command-line argument -com.apple.CoreData.SQLDebug 1 to have Core Data dump all the SQL commands it performs to the console, then it can be a helpful performance diagnostic to open your persistent store in SQLite and check out the query plans, to make sure you're indexing the correct things.

Answer 3

Have not export any iOS SQLite file so I dont know how do you export yours. Maybe you need analysis your file bytes code? Look this http://www.sqlite.org/fileformat.html