I'm diving in to iPhone development and I'm building an iPhone app that uses the Core Data framework and my first task will be to get the model setup with a view that will display it. Thus far, I have the model defined and my Managed Object Files created, but I don't have a database with any sample data.
What's a quick way to create a DB that conforms to my schema?
Are there any tools that can generate a sample DB using my schemas? Or do I have to create this sample data by hand?
Once the DB is created, are there any good tools I can use to directly manipulate the data in DB for testing purposes?
Thanks in advance for your help! I'm going to continue researching this question right now.
This is very close to the question "Provide Base Data for Core Data Application?" Additionally, my answer to this question describes how you can quickly build a Mac application that lets you create or edit a Core Data database that is compatible with your iPhone application's data model.
Beyond that, you can use the application Core Data Editor to do what its name describes.
I assume you've already created a working app that uses sqlite as persistent storage for your data model.
Have a look into the AppDelegate.m file to search for the sqlite database name and location, then run your app in the iPhone Simulator.
Use Spotlight to search for the SQLite database created by the app in the simulator, usually this is /Users/<Username>/Library/Application Support/iPhone Simulator/User/Application/<Application GUID>/Documents/<database name.sqlite>
Now you only have to copy that file to a working folder, open it using sqlite3 (www.sqlite.org), then type .schema to retrieve the database schema.
Now populate it, either by hand or using a python/ruby/whatever script!
Unfortunately, i'm not aware of any tool that will populate a db by simply feeding them the schema.
For directly manipulating the data, sqlite3 provides you with a command line utility that's really handy for that purpose.
When you're finished, add the file with sample data to your App project.
Related
I have used extensively core data in my applications. Generally I need to submit the applications using a pre-populated database.
I generally create zillions of lines of code to populate the database, then I extract it from the applications directory and include it on the bundle. Is there a easy way to do that? Is there any way to populate a core data database created on Xcode using, for example, a CSV file and an external app?
thanks.
The usual way is to create the entries at the first launch.
If you want to import data from a CSV file, then you need a parser.
I can recommend this one: https://github.com/davedelong/CHCSVParser
You don't have any easy way to do that with Xcode.
Basically what I do in this kind of case: I build a second target dedicate to pool the database and create object with a fixed persistent store url relative to the workspace in the filesystem.
Two questions about Core Data:
1. Is it possible to see the actual data(the db tables) that is stored when using core data?
2. When using the iPhone simulator i can delete the core data db by resetting the simulator. But how can i delete the core data db when using a real device?
Your Mac comes with a command line tool sqlite3. You can use it to do queries against the core data database. Not sure if that violates any rules against reverse engineering that might exist in any license agreements.
You can delete the db for convenience during development by deleting your app from the device and reinstalling it. If you don't want to do it by deleting the app, you will have to write some code in your app to delete it I think.
You can directly view an sqlite store using any sqlite tool including the command line sqlite3 tool. However, (1) Core Data uses a custom undocumented schema so looking at the store doesn't tell you much and (2) the structure of the sqlite store file itself has little relationship to how the managed objects behave in memory. Core Data isn't an sql wrapper. It just takes the managed objects apart to store them in SQL. SQL is just an option and Core Data works fine without it.
To "delete the core data db" you simply delete the persistent store file. Look where you initialize the persistentStoreCoordinator (in the Xcode templates, it's in the app delegate.) The URL for the persistent store/s will be there. Just close down the Core Data stack and then delete the store file with NSFileManager. Then restart the Core Data stack.
I've seen tutorials in books and on websites that offer .sqlite files for download. The sqlite files are used for Core Data.
How do I get a .sqlite file FROM an app or core data store on TO my desktop?
If you are going to create a pre-populated sqlite file to be used with Core Data then you must create it with Core Data. It is trivial to create a basic desktop application for data entry and use that to create the file and then embed it in your iOS device.
Do not attempt to duplicate the data structure or linkage within the file by hand. You might get it to work but you will spend way more time trying to get it to work and it is going to eventually fail. The internal structure of a Core Data sqlite file should be considered like a private API. The structure is not public and can change without notice.
If you are specifically trying to create a Core Data store, you use this method:
NSPersistentStoreCoordinator
addPersistentStoreWithType:(NSString*)storeType
configuration:(NSString*)configuration
URL:(NSString*)storeURL
options:(NSDictionary*)options
error:(NSError**)error
You must have already associated a NSManagedObjectModel with your persistent store coordinator object. If the store at storeURL does not exist, it will be created; otherwise it will be opened.
These might help: http://www.sqlite.org/cvstrac/wiki?p=ManagementTools
I like to use this Firefox plugin:
https://addons.mozilla.org/en-US/firefox/addon/5817/
You can create a new .sqlite file, change existing databases, and browse through your data.
There's a command line program download-able from sqlite.org (in the standard download) that can be used to create a blank database with a schema. Usually the database file is compatible across operating systems and devices.
So I have a question about the ideal setup for an app I am getting ready to build. The app is basically going to be a memorization tool and I already have an sqlite database full of content that I will be using for the app.
The user will navigate through the contents of the database(using the uipickerview), and select something for memorization. If that row or cell of data is selected, it is put into a pool or a uitableview that is dedicated to showing which items you have in your "need to memorize" pool. When you go to that tableview, you can select the row, and the actual data would be populated. All information in the tableview would be deletable, in the event that they don't want it there anymore...
Thats it.
I know that with database interfacing, there are a few different options out there, in this particular setup, is core data the easiest approach? Is there any other way that would be better? I am just kind of looking for a point in the right direction, any help is greatly appreciated!!
Core Data is going to be the easiest. You will want to migrate your data from your raw SQLite file to a Core Data generated SQLite file as Core Data is designed to manage its own file 100%. Fortunately you can do this with a quick command line app on the desktop and then copy the resulting Core Data Sqlite file into your application bundle for later use on iOS.
Doing raw SQLite on iOS is possible but a real headache to get right compared to the ease of use that Core Data offers.
Update
Core Data on iOS produces identical files to Core Data on the Desktop. Therefore you can develop a quick and easy app for the desktop that say for example takes the following inputs:
Table/Entity Name
CSV of a row of data
Then it would create a Core Data entity based on the entity name and insert the data into that row.
With that in place it would be trivial to do a bash script to loop through the all of the tables and the rows in those tables to create your new SQLite file.
Hmmm, might have to do a blog post some time on CIMGF about this :)
I have a Core Data based application that stores hierarchal data displayed using a series of UITableViews. To illustrate my app functionality to the user I would like to pre-populate my database/app with some dummy values. This data would be available upon installation on the user's iPhone/iPod Touch.
What is the best way to achieve this?
Create the data and include it in the app bundle. On first launch, copy that sqlite file to the documents directory and then stand up the core data stack afterwards.
Personally i would create a desktop app using the same model to do the initial data entry to make it easier on you. From there take the sqlite file that is generated and include it in your appilcation.