I want to fetch data from Parse and save/load data from local databases without using Parse pin/unpin features due to some needs. I have a timestamp db (has a column called dbname, and a column called timestamp) and a actual db for data on both local and Parse. And my app will first compare the timestamp on local with Parse. If the timestamps are different, then my app will update the local DB. My questions are that: Is this a correct way to improve app's performance (i.e. reduce loading time, any demos on github?)? Where should I implement this? Should I do it in app delegate or in the first view controller? What will the most efficient way to do this? Is there any other ways to do this?
You must have to read this Apple iOS developer library
from the Set up Set Up
Try to understand the architecture of the iOS app.
Related
I am currently developing an app with a big database. Think of the app as similar to TripAdvisor in the following way: multiple cities with different databases, each between 5, 10, 20, 30 MBs. My whole app is based on this data: every view needs some part of it.
I'm having big trouble finding the correct way to handle this huge chunk of data. I am currently using CoreData: I think it is a great tool, and for offline mode, it definitely works great.
The problem is, I can't really combine it with "online" mode. If the user doesn't want to store the data for X/Y reason, I'm not sure how I should handle the data.
Simply allocate it in variables that will be released anyway, or is there a better way to handle the data?
Right now I am stocking it into CoreData without saving it: I know this is absolutely not a good way to manage it. How could I achieve this?
What is the best way to handle online data and then simply stock it if the user wants it offline too?
Option 1:
Data is always static/ not change data frequently:
You should have data on online. You can fetch data by webservice and store it to local database(i.e core -data). For example: Bible, Quran app.
Option 2:
Data change frequently and user need to update frequently:same as above. Additionally, from server you send notification(i,e push-notification) to app that server has a new data.After getting notification in app, download and save data to you database.
I am developing an app in which I am using SQLite database.what I am trying to implement is
Load data from server and add these data to local database.
Show data to user from local database not directly from server, so that if there is no internet connection user can see some old data.
This will be static data always but it will be huge amount of data.
Now I want to update this data for a particular time duration say in every 24 hours but this I want to do in background. This is about loading data but some data will be for uploading this will be small amount of data.
I have seen apple IOS-7 release features(Background fetch and Background Transfer Service),but what I understood is we can only download files from server by using this,I read this from this answer Here
but I have to deal with JSON. I have searched a lot how should I perform this but not getting any right solution.
I have this tutorial for background tasks
Background Transfer Service
there are many more tutorials but I am not getting how I can implement it in my case.
if I am not clear with my question please let me know I will provide more details.
Thanks for all help.
one more point I want to tell, database structure is almost same as server database.
In my opinion a better solution would be if you save the time of the latest update of the database. Whenever the user opens your app (this is the only time he wants to see new information) and your saved timestamp is at least 24hours ago, you should update the data in your database.
Given the recent addition of local datastore for iOS to Parse, it should be possible to rely exclusively on Parse to manage app's database, thus totally avoiding Core Data. Does this sound like a good idea? What would be the pros and cons of such an approach?
In particular, I am wondering whether it will be possible to pre-populate Parse local datastore with some data, and include this database as a part of the app when submitting to appstore.
UPDATE
From the comments that were posted, it seems that people misunderstood my intended use case. Sorry guys, I should have made my question more clear from the beginning. Let me clarify it now, anyway.
So, there is some amount of data in Parse database on the web, same for every user, e.g. a catalogue of books. It will be updated every now and then. What I want is to publish an app on App Store which is pre-populated with Parse data store, as it stands at the moment when the app is published. For that to happen, I'd like to pin all available data when building my app and ship that data store along with the app. The problem is that the pinned data will be stored on device's (or emulator's) file system, it won't be part of the project. That's why if I build the app and submit it to app store, the data won'd be included.
Any suggestions how to attach the local data store to the app?
The local data store is stored in the sandboxed part of the filesystem in iOS. When you package the store with the app, it'll live in the signed application folder, not in the location Parse expects it to be.
So, if you were looking to do this, you'd need to include your default local data store in the application on building/submission, and copy it into the location Parse expects it to be in (which is Library/Private Documents/Parse and the file is called ParseOfflineStore) when your application starts up. This must happen before you call enableLocalDatastore, or an empty one will be initialized.
It should be possible!
Read this in the docs. Parse has a highly resourceful and fully documented guide for their backend.
https://parse.com/docs/ios_guide#localdatastore
Per my comment above concerning didFinishLaunchingWithOptions; it has been a place for your to create objects on launch, I have been doing that for a long time. Especially with channels. However, by enabling the local data store you can access those objects you pinned or created with a simple query with no reachability per your concern. Either way they both are created on disk. Core Data has a lot more cons. Especially with NSFetchedResultsController and the flexibility it offers. It's all up to you what you want to do with your app. PFQueryTableViewController isn't bad but if your direction and vision for your app is to be exclusively Parse then why not. It's a great feature. However I didn't see anything in the docs about the local queries effecting your limit so I would suggest looking into that if you have a large audience performing numerous queries per second.
Take advantage of their docs. They do a great job at keeping us informed.
I have to ship a simple app with a very tight deadline so I have no time to learn anything othen than what I know (meaning learning Core Data for example). Would it fine to use NSUserDefaults to store data for my app? It's almost like a check list app where users have list of items with some data accompanying each item.
Other than that I would be using a service like Parse which I can handle thanks to having built my last app with it.
Would Apple reject an app if you use NSUserDefaults for something other than settings/preferences?
Thanks!
From Apple's documentation:
The NSUserDefaults class provides a programmatic interface for interacting with the defaults system. The defaults system allows an application to customize its behavior to match a user’s preferences. For example, you can allow users to determine what units of measurement your application displays or how often documents are automatically saved. Applications record such preferences by assigning values to a set of parameters in a user’s defaults database. The parameters are referred to as defaults since they’re commonly used to determine an application’s default state at startup or the way it acts by default.
[...]
Values returned from NSUserDefaults are immutable, even if you set a mutable object as the value. For example, if you set a mutable string as the value for "MyStringDefault", the string you later retrieve using stringForKey: will be immutable.
In other words, this is not the place to store mutable application data.
If the checklist data is going to be modified by end users (i.e. adding new items, or editing the text of the items on the checklist) it really would be worthwhile to learn how to use Core Data. Over the years it really has become very easy to learn and use.
You can find a great series of Core Data tutorials at http://code.tutsplus.com/series/core-data-from-scratch--cms-653
If you're looking for something that's been updated for iOS 8 and Swift (although they're mainly syntax changes for the new language), you can check out http://www.raywenderlich.com/85578/first-core-data-app-using-swift.
Apple wouldn't reject even if you unnecessarily burden NSUserDefault. But users of your App will definitely uninstall it or OS will kill it if app crashes or hangs their iPhone.
NSUserDefault : is a fast way to access the data. it stores in (key,value) pair and lives as long as your app is installed in phone. Usually session based small amount of data is supposed to be stored in it. Not ur entire database.
Database (CoreData or Sqlite) : Behind the seen Coredata is also a sqlite with objects talking to each other(Think in terms of model instead of tables if using Coredata).
I simple suggest you use Coredata if your data by any chance is big or expected to get big. CoreData wont take much time.
Yes, you can store data in NSUserDefaults, which will be the quick and dirty method to store data locally.
You could use Core Data, though I prefer to just use FMDB and write my own SQLite statements. You could also use NSFileManager and just read and write everything to a JSON file. Parse will probably be overkill if all you are doing is storing a list of check list objects.
Go for NSUserDefault fro now !
When the App is submitted fro approval, look at SQlLite. this will be useful for the next projects.
Parse... sure but make sure it's not overkilling especially if you have limited amount of data
Good Luck !
I am currently creating an iOS app, which connects to a database and asynchronously downloads a JSON object of data to display in a table view.
As it currently stands, this is an ok way to do it. However, when the database starts getting much larger, this will cause a massive inconvenience. I'm reasonably proficient in Objective-C but not so much in the database side of things. What would be the best way to get this data from the server, and keep it in the app? At the moment, I have a custom class object storing the data for each of the 'objects' in the JSON object. There will however be many other aspects of the app that the database will handle, such as invites, logins and user details.
Would core data be the way to go? I.e duplicating the database (to a certain extent) and storing it locally, then accessing from there. As I said, i'm not really sure which route to take here, so any advice would be real appreciated.
Core location is for handling location (satellite (and wifi) positionning).
I guess you mean Core Data. Core Data is a graph object model which allows you to manipulate data as objects. You don't dig directly into the database, you ask for objects instanciation through predicates (kind of where clause in SQL) and the manipulate the objects.
This stated, it all depends on what is a "big" database. If it's really big you could consider copying locally a part of it and ask for what's remaining from the server through your webservice.
Another question that you could ask yourself is the quantity of data that never change and if your website database and your app database needs to get synchronized (if your website database is always changing then it would be dumb to copy it in your app totally and always synced your app..).
Links :
Introduction to Core Data
Difference between Core Data and a Database (Cocoa With Love)
edit :
A question you can ask yourself is where your data needs to be saved ?
if your app is just for printing 20 cells out of a total of 200 cells then i would go for a total download of your 200 cells. The load of the other cells will be with no delay after first download, especially appreciated if you're using table view cells with reusable cells
is a delay of some seconds acceptable between the 20 first cells and the 20 following ? I think there is no real "good" answer to your question, it depends on many factors (purpose of your app, acceptable time between loads, does the info needs to be modified and saved back to server or locally, what kind of customers, what your app will do with the cells, if you have a database locally will it be totally independant from "mother" database (if no, what kind of synchronization), etc.)
Trying to sum up things according to what I've understood of your needs, I would say that webservices is good if you just need to retrieve info and exploiting it after without saving it back (even if you can do it actually having services allowing you to do it), having a database locally is good if you need your app to be independant from your server in some ways.
Only you has the key to answer all this and take a decision according to your needs and your knowledge of your application and your customers.
Something like JSON or SOAP is the way to go with getting structured data from a web service into objects in your iPhone app.
Storing relational data on the iPhone itself is easy with SQLite. Here's a decent looking tutorial.
Make things easy for yourself by writing a data layer, abstracting away calls to the database, to avoid dotting SQL queries all over your code in places it shouldn't be, like the UI.