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.
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.
I've looked around for this but haven't found what I'm looking for. I need some data to basically come pre-loaded in the app. I know that I could just put it all in on the first launch but would like to stay away from a long load time on the first launch and have it already loaded.
Is it possible to insert entities into core-data so that they are hard-coded in?
Yeah, you include a a pre-filled data store in your app bundle and copy it from the bundle to the documents directory as part of the app launch process - check if the data store exists and, if not, do the copy. You do this prior to accessing the Core Data stack for the first time.
There are a few ways you could do this. The lazy programmer way is to enter your default data into the app, either on the phone or in the simulator, grab the data store file, and include it in your Xcode project. The downside is it doesn't work well if you need to go back and edit the data model later.
The other option is to create an editor app on the Mac that uses the same Core Data model as your iPhone app (they're compatible) and edit the data in your Mac app. Jeff Lamarche talks a bit about this in one of his blog postings. I've done something similar, except I wrote a command line tool to download the latest data from a web site (in my case, XML data) and parse the XML into NSManagedObjects.
This StackOverflow post talks about a bit more complex option of having two data stores - one for your system data and one for your user data - and letting Core Data use both stores at runtime.
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'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.
I'm doing an iPhone application. In this app, I just want to have a database to be used as a looked up table for values in my app. The only thing the database will do was to supply me the values I needed depending on the query of the program. It won't do any addition or deletion in the database. My question was how do I initialize a default data on the application using CoreData. So that when the program starts It already had all the values needed.
If you have other suggestions of what is better do or what are other alternatives, please tell me.
Thanks.
I would create a simple Mac application, starting from the template for a Core Data document-based application. Copy your existing .xcdatamodel over the default one in the project (or add the new data model and be sure to rename anywhere that refers to the default model). Open up the XIB file for the document window in Interface Builder and drag the Core Data Entity item into it from the Interface Builder library inspector. From the resulting dialog, choose an entity to display and select an interface to display it in.
What this will do is create a fully functional interface for adding, removing, or editing the properties of that entity type. Everything should be hooked up via Cocoa Bindings so that you don't need to write a line of code for this to work. You can add interfaces for each entity type in your model this way.
This will let you quickly enter and edit data within a Core Data document, which you can then save out to disk and add as a resource to your iPhone application. The SQLite database structures are fully compatible between the desktop and iPhone Core Data implementations, so I've found that this is a quick and easy way of testing your iPhone Core Data code.
Please refer to the Core Data Programming Guide, or see below (copy from the PG):
"
How do I initialize a store with default data?
There are two issues here: creating the data, and ensuring the data is imported only once.
There are several ways to create the data.
You can create a separate persistent store that contains the default
data and include the store as an application resource. When you want
to use it, you must either copy the whole store to a suitable
location, or copy the objects from the defaults store to an existing
store. For small datasets, you can create the managed objects
directly in code.
You can create a property list—or some other file-based
representation—of the data, and store it as an application resource.
When you want to use it, you must open the file and parse the
representation to create managed objects.
You should not use this technique on iOS, and only if absolutely necessary on Mac OS X. Parsing a file to create a store incurs unnecessary overhead. It is much better to create a Core Data store yourself offline and use it directly in your application.
There are also several ways to ensure that the defaults are imported only once:
If you are using iOS or creating a non-document-based application for
Mac OS X, you can add a check on application launch to determine
whether a file exists at the location you specify for the
application’s store. If it doesn't, you need to import the data. For
an iOS-based example, see CoreDataBooks .
If you are creating a document-based application using NSPersistentDocument, you initialize
the defaults in initWithType:error:.
If there is a possibility that the store (hence file) might be
created but the data not imported, then you can add a metadata flag
to the store. You can check the metadata (using
metadataForPersistentStoreWithURL:error:) more efficiently than
executing a fetch (and it does not require you to hard code any
default data values).
"
As mentioned above, generally we need to create a pre-populated default store with code, then use it as a
resource file, and copy it from resource bundle to document directory if the coredata file is missing. Please search the CoreDataBooks code example in your Xcode Organizer (or Apple Developer Center), and look at the - (NSPersistentStoreCoordinator *)persistentStoreCoordinator method.
I racked my brain for hours attempting to solve this. What I came up with was simply not to save the database. That way, it will be initialized each time the app is opened. If you save it, it will continue to duplicate.
I would write a tool that populates a database with the data you want in it, generate the db at build time and stuff it in your resources folder. If you are not going to write to it you can just leave it there and access it directly, if you ever did want to write to it you would need to copy it somewhere you are allowed to write (like the documents folder).