Managing SQLite Database with SwiftyDB


Selecting a manner for storing knowledge completely is one thing that’s at all times wanted when growing purposes. There are numerous choices we will decide from: To create single information, to make use of CoreData or create a SQLite database. The final choice contains some additional trouble because the database should be created first, and all tables and fields to be already outlined earlier than an app makes use of them. Moreover, and from the programming standpoint, it’s not that straightforward to handle a SQLite database when knowledge must be saved, up to date or retrieved.

These issues appear to vanish when utilizing a comparatively new library that was popped on the GitHub known as SwiftyDB. It’s a third-party library, which, because the creator says, is a plug-and-play element certainly. SwiftyDB reliefs builders from the effort of making a SQLite database manually, and from defining all required tables and fields. That occurs routinely by the library utilizing the properties of the category (or lessons) used as knowledge fashions. In addition to that, all database operations are carried out beneath the hood, so builders can concentrate on the implementation of the app logic solely. A easy but highly effective API makes it actually a bit of cake when coping with the database.

It’s essential to say although that you just shouldn’t anticipate SwiftyDB to make miracles. It’s a dependable library that may do fairly effectively what it’s presupposed to do, however there are nonetheless some lacking options which might be most likely meant to be added within the (close to or distant) future. Nonetheless, it’s nonetheless remaing a fantastic device that deserves some particular consideration, due to this fact on this tutorial we’ll undergo the fundamentals of SwiftyDB.

In your reference, you will discover its documentation right here, which you must undoubtedly see after having gone by means of this textual content. In case you have been at all times prepared to work with SQLite databases however hesitated to take action, I consider that SwiftyDB is an efficient begin to try this.

With the above mentioned, let’s get going with the exploration of a brand new, fairly promising device.

In regards to the Demo App

In our submit as we speak we’re going to create a very easy word taking app able to doing all the fundamental operations one would anticipate:

  • Checklist notes
  • Create new notes
  • Replace current notes
  • Delete notes

Apparently, SwiftyDB goes to take cost of managing the info into an SQLite database. All of the listed operations above are adequate to reveal every part you want so can get began working with SwiftyDB simply.

To make it attainable for us to remain into the purpose, I’ve created a starter mission which you must obtain and start with. Once you get it, open it in Xcode and navigate round so that you get acquainted with it. As you’ll see, all the fundamental performance is there, with the many of the data-related options to be lacking. It could be nice in case you would additionally run the mission at the least as soon as, so that you see what’s all about.

The app is navigation based mostly, and within the first view controller there’s a tableview the place all notes are supposed to be listed.

By tapping on an current word we’ll be capable of edit it and replace it, and when swiping to the left we’ll be capable of delete it:

t50_2_delete_note

Composing a brand new word is feasible by tapping on the plus (+) button on the navigation bar. In an effort to have a adequate working instance, right here’s a listing of actions that we will carry out when enhancing a word (new or current one):

  1. Set title and physique for the word.
  2. Change the font title.
  3. Change the font dimension.
  4. Change the textual content coloration.
  5. Import photos to the word.
  6. Transfer the photographs round and place them to a special place.

All values matching to the above operations will likely be saved to the database. To make it a bit extra clear for the final two elements particularly, the precise photos are going to be saved to the paperwork listing of the app, whereas we’re going to save simply the title and body for every picture to the database. However not simply that; moreover we’re going to create a brand new class for managing photos (with the small print are coming later).

t50_3_edit_note

A final however necessary element I’ve to say about is that regardless that you’re downloading a starter mission to work on, by the tip of the following half you’ll be having a workspace. That’s as a result of we’ll use CocoaPods to obtain the SwiftyDB library, and another dependencies that come alongside.

Please get going whenever you’re as much as it, however first, shut the starter mission in case you have already opened it in Xcode.

Putting in SwiftyDB

The very first thing we’ve to do is to obtain the SwiftyDB library and use it in our mission. Merely getting the library information and including them to the mission isn’t going to work, so we’ve to carry out the set up utilizing the CocoaPods dependency supervisor. The method is straightforward, and also you’ll be capable of do it very quickly in any respect, even in case you have by no means used CocoaPods earlier than. For you reference nonetheless, have a look to the earlier hyperlink.

Putting in CocoaPods

We’re going to start by putting in CocoaPods to our system. You probably have put in CocoaPods already please skip this step. If not then go forward and open Terminal. Sort the next command to put in CocoaPods:

Press Return, present your password and sit again whereas the obtain course of is going down. Don’t shut Terminal as soon as it’s completed, we’re nonetheless needing it.

Putting in SwiftyDB and Different Dependencies

Navigate to the folder the place the starter mission exists by utilizing the cd command (nonetheless in Terminal):

It’s now time to create a Podfile that describes the library (or libraries) we need to obtain to CocoaPods. The simplest manner to try this is by typing the next command and let CocoaPods create one for us:

A brand new file named Podfile will likely be created to the mission folder. Open it utilizing a textual content editor (ideally not TextEdit), and modify it in keeping with the following snippet:

t50_4_podfile

The road that may truly do the entire job is the pod "SwiftyDB". CocoaPods will obtain SwiftyDB library and all of its dependencies by utilizing that line, and it’ll create some new subfolders together with an Xcode workspace.

When you end enhancing the file, save and shut it. Then, just remember to’ve closed the starter mission on Xcode and return to Terminal. Sort the following command:

t50_5_pod_install_2

Wait once more for a couple of moments, and then you definitely’re able to go. As an alternative of opening the starter mission, open the NotesDB.xcworkspace on Xcode this time.

t50_6_folder_after_installation

Starting With SwiftyDB – Our Mannequin

Contained in the NotesDB mission there’s a file known as Word.swift, however it’s presently empty. That is our entry level as we speak, as we’re going to create a few lessons that may symbolize a word entity programmatically. In a extra theoretical degree, our upcoming work right here consists of the Mannequin half within the iOS MVC sample.

What we’d like initially is to import the SwiftyDB library, in order you guess go to the highest of the file and add this line:

Now, let’s declare our most necessary class on this mission:

When working with SwiftyDB there are a couple of however particular guidelines to comply with, and within the above class header line you’ll be able to see two of them:

  1. A category with properties meant to be saved in a database utilizing SwiftyDB should be a subclass of the NSObject class.
  2. A category with properties meant to be saved in a database utilizing SwiftyDB should undertake the Storable protocol (it’s a SwiftyDB protocol).

Now we’ve to consider the properties we need to have on this class, and right here it comes once more a brand new rule from SwiftyDB: The datatypes of the properties should be any of these listed right here so as to have the ability to load whole Word objects, as an alternative of straightforward knowledge (array with dictionaries) when retrieving knowledge from the database. If there are properties with “incompatible” datatypes, then we’ll must take additional actions so we convert them into the instructed ones (we’ll see that in particulars in only a whereas). By default, properties with such datatypes are merely ignored by SwiftyDB when it’s about time to avoid wasting to database, and no respective fields are created to the desk. Additionally, we’ll give particular remedy to another properties within the class that we don’t actually need to be saved to the database.

The final rule for now says {that a} class that conforms to the Storable protocol should essentially implement the init methodology:

Now that we’ve all the data we’d like, let’s begin declaring the properties of our class. Not all for now, as a few of them require further dialogue. Nonetheless, listed below are the fundamentals:

Pointless to remark any of them, apart from the primary one. When that object will get initialised it’s going to create a brand new database (named notes.sqlite) if it doesn’t exist and it’ll create a desk routinely. The desk fields will match to the properties having a correct datatype. Then again, if the database already exists, it’s going to simply open.

As you would possibly discover, the above properties describe a word and all of the attributes we need to save (title, textual content, textual content coloration, font title and dimension, creation and modification dates), however there’s nothing there relating to the photographs {that a} word can presumably have. Deliberately, we’re going to create a brand new class for photos, the place we’ll retailer two properties solely: The body and the picture title.

So, nonetheless being within the Word.swift file, create the next class above or under the prevailing one:

Word that the body is represented as a NSData object on this class, and never as a CGRect. It’s essential to do it that manner, so we will simply retailer that worth to the database later. You’ll see shortly how we’re going to deal with it, and also you’ll additionally perceive why we undertake the NSCoding protocol.

Again to the Word class, let’s declare an ImageDescriptor array as proven subsequent:

There’s a limitation that now’s the perfect time to say about, and that’s the indisputable fact that SwiftyDB would not retailer collections to the database. In easy phrases, that signifies that our photos array won’t ever be saved to the database, so we’ve to determine methods to cope with this. What we’re allowed to do is to make use of one of many supported datatypes (see the hyperlink I offered slightly after the start of this half), and essentially the most appropriate datatype is NSData. So, as an alternative of saving the photos array to the database, we’ll be saving the next (new) property:

However how are we presupposed to go from the photos array with ImageDescriptor objects to the imagesData NSData object? Effectively, the reply is by archiving the photos array utilizing the NSKeyedArchiver class and producing that manner a NSData object. We’ll see later how that is actually being performed in code, however now that we all know what we’ve to do, we should return to the ImageDescriptor class and have some additions.

As , a category could be archived (in different languages often known as serialized) if solely all of its properties could be serialised too, and in our case that is attainable, because the datatypes (NSData and String) of the 2 properties within the ImageDescriptor class are serialisable. Nonetheless that’s not sufficient, as we additionally must encode and decode them with a purpose to efficiently archive and unarchive respectively, and that’s why we really want the NSCoding protocol. By utilizing it we’ll implement the strategies proven subsequent (one in all them is an init methodology), and we’ll correctly encode and decode our two properties:

For extra details about the NSCoding protocol and the NSKeyedArchiver class have a look right here and right here, it’s pointless to debate extra about them right here and now.

Along with all of the above, let’s outline a fairly helpful customized init methodology. It’s actually easy, so no must make any feedback:

At this level our first fast assembly with the SwiftyDB library involves its finish. Despite the fact that we didn’t do a lot SwiftyDB stuff, this half was essential for 3 causes:

  1. To create a category that will likely be used from the SwiftyDB.
  2. To find out about some guidelines utilized when utilizing SwiftyDB.
  3. To see some necessary limitations relating to the datatypes that may be saved within the database utilizing SwiftyDB.

Word: In case you’re seeing some errors proper now on Xcode, then construct the mission as soon as (Command-B) to eliminate them.

Major Keys and Ignored Properties

It’s at all times beneficial to make use of major keys when coping with databases, as such keys may help you uniquely determine data within the database tables and carry out numerous operations by utilizing them (for instance, replace a particular file). You’ll find right here a great definition about what a major secret is.

It’s straightforward to specify a number of properties of a category as the first key (or keys) for the respective desk within the database in SwiftyDB. The library supplies the PrimaryKeys protocol, which must be carried out by all lessons that the respective tables ought to have a major key so their objects to be uniquely recognized. The best way to try this is sort of easy and customary, so let’s get into the purpose immediately:

Within the NotesDB mission you’ll discover a file named Extensions.swift. Click on it on the Undertaking Navigator so that you open it. Add the next traces there:

In our demo, we wish the noteID property to be the one major key within the respective desk within the sqlite database. Nonetheless, if extra major keys are required, then you definitely simply have to put in writing them within the row separated by comma (for instance, return ["key1", "key2", "key3"]).

In addition to that, not all properties of a category ought to at all times be saved to the database, and you must explicitly order SwiftyDB to not embody them. For instance, within the Word class we’ve two properties that aren’t going to be saved to the database (both as a result of they can not or we don’t need so): The photos array and the database object. How can we explicitly exclude these two? By implementing one other protocol that the SwiftyDB library supplies known as IgnoredProperties:

If there have been extra properties we wouldn’t prefer to must the database they need to be added above too. For instance, let’s say that we’ve the next property:

… and that we don’t need it to be saved to the database. In that case, we must always add it to the IgnoredProperties protocol implementation too:

Word: Import the MARKDOWN_HASH6211c316cc840902a4df44c828a26fbeMARKDOWN_HASH library to the MARKDOWN_HASH1dbda56f2122b1744ebf59bb64bbffdfMARKDOWN_HASH file in case you see any errors.

Saving a New Word

Having performed the naked minimal implementation within the Word class, it’s time to show to the functionalities of the demo app. We nonetheless haven’t added any strategies to our new class; we’ll achieve this by following the implementation stream of all of the lacking functionalities.

So, the very first thing we’d like is having notes, due to this fact the app should be informed methods to save them correctly utilizing the SwiftyDB and our two new lessons. That is going to happen principally within the EditNoteViewController class, so it’s about time to open the respective file utilizing the Undertaking Navigator. Earlier than we write the primary line of code right here, I contemplate fairly necessary to spotlight the many of the properties discovered there:

  • imageViews: This array holds all of the picture view objects that include photos added to a word. Please don’t overlook that this array exists; it’ll change into helpful shortly.
  • currentFontName: It holds the title of the presently utilized font to the textview.
  • currentFontSize: It’s the font dimension of the textual content within the textview.
  • editedNoteID: The noteID worth (major key) of a word that’s about to be up to date. We’ll use it later.

Because the common performance already exists within the starter mission, what we’ve to do is to implement the lacking logic within the saveNote() methodology. We’ll start by doing two issues: First we received’t permit saving if there is no such thing as a textual content within the title or the physique of the word. Second, we’ll dismiss the keyboard if it’s appeared by the point of saving:

We’ll proceed now by initializing a brand new Word object, and by assigning the proper values to the correct properties. The pictures want particular remedy, and we’ll do it proper after.

A couple of feedback now:

  • The noteID property expects any Int quantity that may work as the first key. You possibly can create or generate any worth you need so long as it’s distinctive. On this case we set the integer half of the present timestamp as our major key, however usually this isn’t a good suggestion in actual world purposes because the timestamp accommodates too many digits. Nonetheless for our demo software it’s simply tremendous, because it additionally consists of the simplest choice for having a novel int worth.
  • As we save a word for first time, we set the present timestamp (expressed as a NSDate object) to each creation and modification date properties.
  • The one particular motion we undoubtedly must take is to transform the textual content coloration of the textview right into a NSData object. That is achieved by archiving the colour object utilizing the NSKeyedArchiver class.

Let’s concentrate on methods to save the photographs now. We are going to create a brand new methodology which will likely be fed with the picture views array. We’ll carry out two issues in it: We’ll save the precise picture of every picture view to the paperwork listing of the app, and we’ll create an ImageDescriptor object for each. Every such object will likely be appended to the photos array.

In an effort to create this new methodology we’re going to make a small detour, and to return to the Word.swift file once more. Let’s see the implementation first, after which we’ll talk about about it.

<

pre lang=”swift”>
func storeNoteImagesFromImageViews(imageViews: [PanningImageView]) {
if imageViews.depend > 0 {
if photos == nil {
photos = ImageDescriptor
}
else {
photos.removeAll()
}

}

Right here’s what’s going down within the above methodology:

  1. For starters we verify if the photos array is initialised or not. If it’s nil we initialise it, if not, we simply take away any current knowledge from it. The second will change into helpful later, once we’ll be updating an current word.
  2. Then for every picture view we create a novel title for its picture. Every title will likely be much like this: “img_12345679_1”.
  3. We initialise a brand new ImageDescriptor object by utilizing our customized init methodology and by offering the picture view body and the picture title as parameters. The toNSData() methodology has been carried out as an extension of the CGRect and you will discover it within the Extensions.swift file. Its objective is to transform a body to a NSData object. As soon as the brand new ImageDescriptor object is prepared, it’s appended to the photos array.
  4. We save the precise picture to the paperwork listing. The saveImage(_: withName:) class methodology could be discovered within the Helper.swift file, together with couple extra helpful class strategies.
  5. Lastly, when all picture views have been processed, we convert the photos array to a NSData object by archiving it and we assign it to the imagesData property. The final line above is the precise purpose that the NSCoding protocol and the implementation of its strategies are required within the ImageDescriptor class.

The else case above might sound reduntant, however it’s required. By default, the imagesData property is nil and it’ll stay like that if no photos get added to the word. Nonetheless, “nil” is just not acknowledged by SQLite. What SQLite understands is the equal of NSNull, and that’s what we offer transformed to a NSData object.

Again to the EditNoteViewController.swift file once more to make use of what we simply created:

Let’s return now to the Word.swift file, and let’s implement the strategy that may carry out the precise saving to the database. There’s one thing necessary you must know at this level: SwiftyDB supplies the choice to carry out any database-related operation synchronously or asynchronously. Which methodology you must choose relies on the character of the app you construct. Nonetheless, I’d counsel to make use of the asynchronous methodology, as this received’t block the principle thread whereas a database operation is in progress, and it received’t have an effect on the person expertise by freezing (even immediately) the UI. However I’m saying once more, it’s completely as much as you.

We’ll use the asynchronous solution to save our knowledge in right here. As you’ll see, the respective SwiftyDB methodology accommodates a closure that returns the results of the operation. You possibly can learn particulars about that outcome object right here, and really I’m recommending to take action now.

Let’s implement now our new methodology so we will talk about extra about it:

It’s straightforward to grasp from the above implementation that we’re going to make use of the identical methodology for updating notes too. We be sure that to set the shouldUpdate Bool worth as a parameter to the strategy prematurely, after which relying on its worth the asyncDataObject(...) will both create a brand new file or it’ll replace an current one.

Moreover, you see that the second parameter in our methodology is a completion handler. We name it with the correct parameter worth, relying on whether or not the saving is profitable or not. I’d counsel you to at all times use completion handlers when you may have duties operating asynchronously on the background. That manner, you’ll be capable of notify the caller strategies when the background activity has completed, and switch any attainable outcomes or knowledge again.

What you see occurring above is what you’ll see occurring in different database-related strategies too. We’ll at all times be checking for an error within the outcome, and we’ll proceed accordingly relying on whether or not there’s any or not. Within the above case if there’s an error, we name our completion handler passing the false worth, that means that the saving was failed. If the alternative case, we go true to point a profitable operation.

Again to the EditNoteViewController class as soon as once more, let’s get completed with the saveNote() methodology. We’ll name the one created proper above, and if the word saving has been profitable we’ll simply pop the view controller. If there’s an error, then we’ll show a message.

Discover the shouldUpdate variable within the above implementation. It will get the correct worth relying on whether or not the editedNoteID property is nil or not, that means whether or not the word is being up to date or not.

At this level you’ll be able to run the app and attempt to save new notes. In case you went step-by-step all alongside the way in which up so far, then you definitely’ll be capable of save your notes with none issues.

Loading and Itemizing Notes

With the creation and saving of recent notes being functioning, we will transfer on and make our app able to loading saved notes from the database. The loaded notes are supposed to be listed within the NoteListViewController class. Nonetheless, earlier than we begin working on this class, let’s create first a brand new methodology within the Word.swift file for loading our knowledge.

The SwiftyDB methodology that performs the precise loading is the asyncObjectsForType(...), and it really works asynchronously. The outcome will include both an error, or a set with word objects (an array) loaded from the database. Within the first case, we name the completion handler passing the nil worth in order to point to the caller that there was an issue whereas loading the info. Within the second case, we go the Word objects to the completion handler so we will use them out of this methodology.

Let’s head to the NoteListViewController.swift file now. Initially, we should declare an array that may include Word objects (these loaded from the database). It’s going to be the datasource of our tableview (clearly). So, on the prime of the category add the next line:

In addition to that, initialize a brand new Word object as effectively, so we will use the loadAllNotes(...) methodology we created earlier:

Time to put in writing a very easy new methodology that may name the one above and cargo all saved objects from the database to the notes array:

Discover that in any case notes get loaded we use the principle thread to reload the tableview. Previous to that in fact we maintain them to the notes array.

The above two strategies are all we’d like for getting the saved notes from the database. That easy! Don’t overlook although that the loadNotes() should be known as someplace, and it will occur within the viewDidLoad() methodology:

Loading the notes is just not sufficient, as we should use them as soon as they’re fetched. So, let’s begin updating the tableview strategies, beginning by the full variety of rows:

Subsequent, let’s show some word knowledge to the tableview. To be particular, we’ll show the title, and the creation and modification dates for every word:

In case you run the app now, all notes that you’ve created up to now will likely be listed to the tableview.

An Various Means To Fetch Information

Only a bit earlier we used the asyncObjectsForType(...) methodology of the SwiftyDB library to load our notes from the database. This methodology returns an array of objects (in our case Word objects) as you’ve seen, and I contemplate this to be fairly helpful. Nonetheless, it’s not at all times that helpful to retrieve objects from the database; there are circumstances the place fetching an array with the precise knowledge values can be extra handy.

SwiftyDB may help you on that, because it supplies another manner for retrieving knowledge. There’s a way known as asyncDataForType(...) (or dataForType(...) if you wish to make synchronous operations), and it returns a colletion of dictionaries on this kind: [[String: SQLiteValue]] (the place SQLiteValue is any of the allowed datatypes).

You’ll find extra right here and right here. I depart it for you as an train to counterpoint the Word class and cargo easy knowledge as effectively, as an alternative of objects solely.

Updating A Word

One of many options we wish our demo app to have is the potential to edit and replace an current word. In different phrases, we have to current the EditNoteViewController with the small print of a word that’s being chosen just by tapping to the respective cell, and retailer to the database its modified knowledge as soon as it will get saved once more.

Beginning within the NoteListViewController.swift file, we’d like a brand new property for storing the ID of the chosen word, so go to the highest of the category and add the next line:

Now, let’s implement the following UITableViewDelegate methodology, the place we discover the noteID worth based mostly on the chosen row, after which we carry out the segue to point out the EditNoteViewController:

Within the prepareForSegue(...) methodology let’s go the worth of the idOfNoteToEdit to the following view controller:

The half job has been performed now. Earlier than we swap to the EditNoteViewController class and proceed there, let’s make one other fast detour by paying a go to to the Word class with a purpose to implement a easy new methodology that may retrieve only a single word utilizing the ID worth that’s being given with. Right here’s the implementation:

The brand new factor right here is that for first time we use a filter with a purpose to apply limitations to the outcomes that will likely be returned. Utilizing the equal(...) class methodology of the Filter class is only a solution to set the filter we wish. Don’t miss to go to this hyperlink to see extra methods for making use of filters when fetching knowledge or objects from the database.

By utilizing the filter within the style proven above, we truly ask from SwiftyDB to load solely these data the place the noteID equals to the worth given as a parameter to the strategy. In fact, only one file will likely be returned as a result of we all know that this subject is the first key and there’s no solution to have a couple of data with the identical key.

The discovered outcomes will likely be returned as an array of Word objects, so it’s essential to get the primary (and solely) merchandise from that assortment. After that, we undoubtedly must convert the picture knowledge (if exists) to an array of ImageDescriptor objects, and assign it to the photos property. That’s necessary, as a result of if we skip it any photos initially added to the loaded word received’t be proven.

On the finish we name the completion handler in keeping with whether or not the word fetching was profitable or not. Within the first case we go the fetched object to the completion handler so it may be utilized by the caller, whereas within the second case we simply go nil as there’s no object.

Now we will head to the EditNoteViewController.swift file, and declare and initialize on the similar time a brand new Word property to the category:

This object will likely be used firstly for calling the brand new methodology we carried out above, after which to include the loaded knowledge from the database.

We’re nearly to load the word specified by the editedNoteID property utilizing the loadSingleNote(...) methodology. For our objective, we’re going to outline the viewWillAppear(_:) methodology, and in there we’ll develop our logic.

As you will notice within the following code snippet, all values will likely be populated correctly as soon as the loadSingleNoteWithID(...) methodology returns the fetched word by means of the completion handler. That signifies that we begin setting the word title, physique, textual content coloration, font, and so forth, however not solely. If there are photos included to the word, we’ll be creating photos views for each, utilizing in fact the frames specified within the ImageDescriptor objects.

Don’t miss that after having populated all values, we assign the word to the editedNote object, so we will use it afterward.

There may be one final step required: To replace the saveNote() methodology, so when a word is being up to date to keep away from creating a brand new Word object, and to not set a brand new major key and creation date.

So, discover these three traces (contained in the saveNote() methodology):

… and change them with the next snippet:

The remaining a part of the strategy stays as is (at the least for now).

Updating the Notes Checklist

In case you examined the app up so far, then you definitely would have undoubtedly realized that the notes record is just not up to date whenever you create a brand new word or whenever you replace an current one. That’s affordable to occur as a result of the app isn’t able to that but, nonetheless on this half we’re about to repair this undesirable behaviour.

As you could guess, we’re going to use the Delegation sample to inform the NoteListViewController class about modifications made to notes within the EditNoteViewController. Our place to begin is to create a brand new protocol within the EditNoteViewController with two required strategies, these proven under:

In each circumstances we offer to the delegate strategies the ID worth of the brand new or edited word. Now, go to EditNoteViewController class and add the next property:

Lastly, let’s revisit one final time the saveNote() methodology. At first find the following line contained in the completion handler block:

Substitute that single line with the next bunch of code:

The correct delegate operate will likely be known as each time {that a} new word is created or an current one is being up to date any longer. However what we simply did consists of the half job solely. Let’s swap to the NoteListViewController.swift file, and to start with let’s undertake the brand new protocol to the header line of the category:

Subsequent, within the prepareForSegue(...) methodology let’s make this class the delegate of the EditNoteViewController. Proper under the let editNoteViewController = segue.destinationViewController as! EditNoteViewController line add the following one as proven to this snippet:

Fairly good, because the many of the job has been performed. What we’re nonetheless lacking is the implementation of the 2 delegate strategies. First, let’s deal with the scenario the place a brand new word has been created:

As you see, we simply fetch from the database the item specified by the noteID parameter worth, and (if exists) we append it to the notes array and reload the tableview.

Let’s see now the following one:

On this case we first discover the index of the up to date word within the notes assortment. As soon as that occurs, we load the up to date word from the database and we change the outdated object with the brand new one. By refreshing the tableview, the brand new modification date of the up to date word will likely be proven immediately.

Deleting Data

The final main function that’s nonetheless lacking from our demo app is the word deletion. It’s straightforward to grasp that we’d like one final methodology carried out within the Word class that will likely be known as evey time we need to delete a word, so open the Word.swift file.

The one new factor on this half is the SwiftyDB methodology that performs the precise deletion from the database, as you will notice within the following implementation. Like earlier than, that is another operation executed asynchronously, and we’ve a completion handler to name as soon as the execution is over once more. Lastly, there’s a filter to specify the row that must be deleted from the database.

Let’s open the NoteListViewController.swift now, and let’s outline the following UITableViewDataSource methodology:

By having added the above methodology to our code, every time you swipe in the direction of left on a word cell the default Delete button will seem to the proper facet. Furthermore, the code that will likely be executed when the Delete button is tapped is the one which will likely be outlined within the physique of the if assertion above. Let’s achieve this:

At first, we discover the correct word object matching to the chosen cell within the notes assortment. Subsequent, we name our new methodology within the Word class to delete it, and if that operation is profitable we take away the Word object from the notes array and reload the tableview so we replace the UI.

It was simply that!

And What About Sorting?

Presumably you’re questioning how we will type our knowledge whereas fetching them from the database. Sorting is sort of helpful, as it may be based mostly on a number of fields, to be carried out in ascending or descending order and ultimately change the order of the returned knowledge. For instance, we may type our notes in a manner that the newest modified notes seem to the highest.

Sadly, SwiftyDB doesn’t help knowledge sorting on the time of penning this tutorial. It is a drawback certainly, however there’s an answer: To manually type the info whenever you want so. To reveal this, let’s create one final methodology within the NoteListViewController.swift file known as sortNotes(). On this one we’ll use the Swift’s default type() operate:

Since NSDate objects can’t be in contrast straight, we convert them to timestamp values (double values) first. Then we carry out the comparability and we return the outcome. The above code results in word sorting the place the newest modified notes are within the first positions of the notes array.

The above methodology should be known as at any time when the notes array will get modified. First, let’s replace the loadNotes methodology as proven subsequent:

Then, we should do the identical to the 2 following delegate strategies:

By operating the app once more now, you’ll see all notes listed on the tableview based mostly on their modification date.

Abstract

Undoubtably, SwiftyDB is a good device that can be utilized in quite a lot of purposes with out a lot effort. It’s actually quick and dependable to what’s made to do, and we will all agree that may cowl a number of wants when a database should be utilized in our apps. On this demo tutorial we went by means of the fundamentals of this library, however that is what you just about must know. In fact, there’s at all times the official documentation you’ll be able to check with for additional help. In our instance as we speak, and for the sake of the tutorial, we created a database with one desk solely matching to the Word class. In real-world apps although, you’ll be able to have as many tables as you need, so long as you create the respective fashions in code (let’s say the respective lessons). Personally, I might undoubtedly use SwiftyDB in my initiatives, and as a matter of reality, I’m planning to take action. In any case, now about it, you’ve seen the way it works and the way it may be used. It’s as much as you to resolve if that is another device in your toolbox or not. Anyway, I hope the time you spent studying isn’t wasted, and also you’ve realized one other new factor, or two. And till our subsequent tutorial comes, have all a beautiful time!

In your reference, you’ll be able to obtain the total mission on GitHub.