Always make a copy of it to the documents directory. Having said all the above, go at the top of the file and create the private class section, by declaring at the same time the two properties as described. So far, so good. Right next you are given the method again, containing this time all the proper code:.
At first, we specify the path to the documents directory and we store it to the documentsDirectory property. Next, we assign the database filename to the databaseFilename property, and finally we copy the database file from the app bundle to the documents directory.
We are based on the NSFileManager class to check for the file existence and to copy it if needed. The above method will be called every time that an object of the DBManager class is initialized. Normally, that code should be executed just once per app install, as the database file should always remain in the documents directory after having been copied in there.
Tutorial on Creating an iOS SQLite Database Application for iOS, iPhone, or iPad | Owlcation
Now, we are ready to go deeper in the details of the SQLite 3 database. Our next step is to implement the heart of our class, the method that will take care of all the work with the database. However, I believe it would be much better to take a quick look at the SQLite 3 functions that we are going to need first, and then proceed to implementation.
In this one, we are going to run both executable and non-executable queries. Based on that, we will make sure to implement it that way so it accepts two parameters: The query itself, and a boolean value indicating whether the query is executable or not. Let me now denote a couple of things. Moreover, the text string results can be converted to other data types and be handled in any desired way by an app.
- High Performance Computing: 4th International Symposium, ISHPC 2002 Kansai Science City, Japan, May 15–17, 2002 Proceedings.
- iOS App Extensions: Data Sharing?
- iOS SQLite Database.
- Principles of Clinical Gastroenterology.
- Create the database.
At second, the fetched results will be stored to a two-dimensional array. Into each index of the results array, there will be another array containing the data of a single row. Personally, I consider this to be the best option for having the result set from the database file to memory.
If you wish so, you could try to modify the implementation and use NSDictionary objects instead. Besides that, there are plenty of comments in the code that will help you understand it much better. First off, go to the private class section, and declare a mutable array property for storing our results, and of course, the private method itself:.
Both of those methods will call this, providing each one the proper arguments. Next, go to the DBManager. Back to the DBManager. Note that if any previous data exist in any of the arrays, we get rid of them before we initialize the arrays again to make sure that nothing remains on memory. Here we go:.
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- Computer Aided Systems Theory - EUROCAST’99: A Selection of Papers from the 7th International Workshop on Computer Aided Systems Theory, Vienna, Austria, September 29 - October 2, 1999 Proceedings;
At first we declare a local array, named arrDataRow. Inside the while loop, we initialize the arrDataRow array and we get the total number of columns existing in the result set. Finally, when the for loop is over, we add the fetched data row to the arrResults array. Things are much simple here. Finally, we need to free up the memory by releasing all used resources, and by closing the connection to database:. That was the last step needed to be performed in the method.
Now that the core method of our class has been implemented, we have only left to make use of it. Open the DBManager. This method accepts as a parameter value the query we want to be executed as a NSString object. The fetched result set is returned as an array, and according to what I said in the previous section, this is going to be a two-dimensional array. The first array represents the rows, while each sub-array represents the columns of each row.
In the first line, we call the runQuery:isQueryExecutable: method and we convert the query to a C string object. At the same time, we specify that the query is not executable. In the second line we return the arrResults array that contains the query results, casting it first to a NSArray object. It would be a bad idea to make the arrResults array public and allow apps to have direct access to it, as then the returned data could be potentially altered before it used. In this one, there is not a return value.
However, the affectedRows property can be used to verify whether there were any changes or not after having executed a query. The database class is ready to be used, but how can we do that without having an actual database to test it?
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On the contrary, we will create just one table, named peopleInfo , with the following fields:. Such a table is just fine to try out all the functionalities we want. Click on the Spotlight icon, and type the Terminal word in the textfield:. Once it gets spotted, hit the Return key on the keyboard, or click on its name with your mouse and the terminal window will appear. We are going to create a new database file named sampledb.
For the record, let me say that you can use any extension you would like for the file, or no extension at all. The most common extensions are:. Personally, I like to give the. Here it is:. Even though this tutorial has nothing to do with offering instructions on how to use the SQLite command line environment, I believe that it would be useful to mention just a couple of commands.
These are the. Notice that both commands are preceded by the dot point. For clear SQL commands, you use no dot mark, but you add the semicolon. The next screenshot of my terminal synopsizes all the above:. Our next task is to add the database file to the Xcode project. You have two options for doing that:.
In most of my tutorials, this part is usually one of the first things you read. However, due to the fact that at the previous sections we created the database class and the sample file, the setup of the interface for our demo app had to be waiting up to this point. On the Project Navigator, click on the Main. Instantly, a navigation controller will be added at the left side of the scene, and a new arrow will point from the navigation controller to the View Controller scene. Right next you are given all the subviews you need to drag from the Objects library to the scene, along with the attributes needed to be specified:.
Besides all the above, select the Navigation Item and set the next two attributes: 1. Title : SQLite 3 Demo 2. Back Button : Go Back. Following the same way you did when you added the database class file to the project, add a new class of UIViewController kind. Head back to the Interface Builder, and select the second, new scene. Immediately, the second view controller scene will turn into the Edit Info View Controller scene. In the black popup window that appears titled Manual Segue , select and click the Push option:. Click on the circle of the connection line, and in the Attributes inspector set the idSegueEditInfo as the identifier value for the segue.
Open the ViewController. Similarly to the previous steps, open the EditInfoViewController. Finally, go to the Interface Builder once again and do the appropriate connections, as shown in the next figure:. As no data still exist in our database, the best point to start from would be to develop the feature of adding a new record.
That requires work in both of our view controllers: In the View Controller class we should make the Add plus button functioning, so we can navigate to the next view controller. Go to the ViewController. Navigating to a new view controller using segues is easy, so the only thing we have to do here is to write just one line of code:. Focusing now our attention on the EditInfoViewController class, the first thing we should take care about is to dismiss the keyboard every time the Done button on it is tapped. He brings a wealth of practical experience to this book with extensive code samples and working apps.
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Build iOS Database Apps with Swift and SQLite
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It really is that easy. All rights reserved. Core Data is a framework for managing an object graph. SQLite is a relational database. Continue reading if you are interested in the long answer. SQLite is a library that implements a lightweight database engine that is incredibly performant and, therefore, a great fit for embedded systems, such as mobile devices. Even though SQLite is advertised as a relational database, it is important to realize that the developer is in charge of maintaining the relationships between records stored in the database. Like many other databases, SQLite stores data and that is what it is good at.
iOS SQLite Database
The SQLite website claims its the most used database in the world. That is the most important difference because there is very little to compare. Core Data and SQLite are solutions to different problems. An object graph is nothing more than a collection of interconnected objects. The framework excels at managing complex object graphs.
The framework is responsible for managing the life cycle of the objects in the object graph.