问题
I have an existing MySQL database, I would like to import the schema into Xcode and create a Core Data data model.
Is there a way (tool, process) to import the CREATE statements so I don't have to build the models "by hand"?
As an intermediary step I could convert to SQLite, I'm not worried about the relationships, foreign keys etc just auto-generating the Entities (Tables) and Properties (Columns).
回答1:
Actually I needed the feature so badly too that I have decided to make an OSX utility to do so. BUT... then I found a utility in the Mac Appstore that (partially) solves this problem (it was free for some time, I do not know its current state). Its called JSONModeler and what it does is parsing a json tree and generates the coredata model and all derived NSManagedObject subclasses automatically. So a typical workflow would be:
- Export the tables from MySQL to xml
- Convert the xml to json
- Feed the utility with that json and get your coredata model
Now, for a more complicated scenario (relationships etc) I guess you would have to tweak your xml so it would reflect a valid object tree. Then JSONModeler will be able to recreate that tree and export it for coredata.
回答2:
The problem here is that entities are not tables and properties are not columns. Core Data is an object graph management system and not a database system. The difference is subtle but important. Core Data really doesn't have anything to do with SQL it just sometimes uses SQL as one its persistence options.
Core Data does use a proprietary sqlite schema and in principle you can duplicate that but I don't know of anyone who has succeeded in a robust manner except for very simple SQL databases. Even when they do, its a lot of work. Further, doing so is unsupported and the schema might break somewhere down the line.
The easiest and most robust solution is to write a utility app to read in the existing DB and create the object graph as it goes. You only have to run it once and you've got to create the data model anyway so it doesn't take much time.
来源：https://stackoverflow.com/questions/3924856/importing-a-mysql-schema-to-xcode-as-a-coredata-data-model