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I’ve previously posted a few things about SQLite including a HOWTO on how to build from their source code.  If you still want to build your own DLL from their source code that is totally fine, but not necessary in most every single case I’ve seen in app usage.  One of the challenges I noted is that since SQLite is a native component and if you are a managed (.NET) app you can’t be architecture neutral anymore (AnyCPU).  What this means is that you have to build your app for each architecture you want to support: x86, x64 and ARM.  The flow of this using SQLite3.dll was that you would have to package, change the DLL, re-package. 

Not anymore.

In working with the great folks on the SQLite team, they’ve packaged the binaries up (for Windows 8 apps) in a nice installer using the Extension SDK format.  What this means is you now add a ‘reference’ to the SQLite binary and based on the architecture being built for your package, it will pull in the right DLL without you having to manage that yourself.  Here’s some step-by-step…

Installing the SQLite for Windows Runtime package

The first thing you want to do is install the package.  You can do this from within Visual Studio itself in all editions.  From the Tools menu, choose Extensions and Updates and then choose the Online section (on the left of the dialog) and search for ‘sqlite’ in the search term.  This will show you the SQLite for Windows Runtime package:

Visual Studio Extensions dialog

Click install my friends.  You will be prompted to restart Visual Studio which you should do.  Go ahead…I’ll wait.

Using the new package in your C#/VB app

Now that you have the SQLite for Windows Runtime package installed in your Visual Studio environment, you want to use it.  In a managed (.NET) app you would do the following steps.

First, create your app (e.g., a Blank XAML app is fine).  Once within your app, use the Add Reference mechanism to get to the next step.  Now you will not be browsing for any DLL directly like you would in a traditional .NET.  What we are adding here is a reference to the Extension SDK…not the library itself, a small but important distinction.  Once in the Add Reference dialog choose the Windows\Extensions view (see on left) and you’ll see SQLite for Windows Runtime.

To correctly use this in a managed app you’ll need to select that *and* the C++ runtime as seen below:

Add Reference dialog

The reason for this is to ensure that your app declares the right dependencies that are needed for the app to run.  The likelihood of the C++ runtime not being on a Windows machine where your app will be installed is extremely rare, but you need to declare this anyway.  Failure to do so will fail your app certification tests.

Now with this involved you can grab a managed wrapper to call the SQLite APIs as I’ve previously described in my HOWTO video.  I personally recommend the sqlite-net library (available via NuGet) to make this easier for you.

NOTE: sqlite-net is available as source in C#.  If you are using a VB app, you would first need to compile the sqlite-net source in a separate DLL so you can just add a reference to that in your VB project.

Using the sqlite-net library you can perform tasks using a model similar to LINQ2SQL where you can have types represent database entities:

   1: public sealed partial class MainPage : Page
   2: {
   3:     public MainPage()
   4:     {
   5:         this.InitializeComponent();
   6:         LoadData();
   7:     }
   8:  
   9:     public void LoadData()
  10:     {
  11:         var dbPath = Path.Combine(Windows.Storage.ApplicationData.Current.LocalFolder.Path, "db.sqlite");
  12:         using (var db = new SQLite.SQLiteConnection(dbPath))
  13:         {
  14:             db.CreateTable<Person>();
  15:  
  16:             db.RunInTransaction(() =>
  17:                 {
  18:                     db.Insert(new Person() { FirstName = "Tim", LastName = "Heuer" });
  19:                 });
  20:         }
  21:     }
  22: }
  23:  
  24: public class Person
  25: {
  26:     [SQLite.AutoIncrement, SQLite.PrimaryKey]
  27:     public int ID { get; set; }
  28:     public string FirstName { get; set; }
  29:     public string LastName { get; set; }
  30: }

Now you just need to specify your architecture for your app (x86, x64, ARM) and when you build, the appropriate sqlite3.dll will be packaged in your app automatically.  This also happens during the packaging step for the store so the right item is included for each architecture-specific package.

WARNING: Do not package in DEBUG mode as you will fail certification.  Ensure that you build/package in RELEASE mode prior to submitting to the store or running the app certification toolkit (also referred to as WACK in some places).  You will get false positives if you are compiled in DEBUG mode.

This should make your development much easier without having to  swap out DLL files each time.

Using the new package in your C++ app

If you are a C++ developer you will do the same steps for installing and adding as a reference to your app.  In the C++ project system there is no 'Add Reference’ menu on the project context menu, but you will choose References and then the Add Reference button shows up.

Once you have the reference to the SQLite SDK then as a C++ developer you can just #include the header and go to work:

   1: #include <sqlite3.h>

Since C++ projects are already architecture-specific you don’t have to worry about the AnyCPU situation because there isn’t one!  You’ll get IntelliSense on the API by just including the header.  The Extension SDK mechanism already includes the C++ props file to help the project system know where to get the header for development and the lib for linking when building.  Most C++ developers will interact with SQLite using the native APIs and not need any additional wrapper library.

Using the new package in your JavaScript app

If you are using JavaScript/HTML to developer your app, you will follow the same flow as the C#/VB flow.  Add a reference to both the SQLite SDK as well as the C++ runtime (to declare the dependency).  As to accessing SQLite in your app, you’ll need a WinRT wrapper library to do that.  The one that seems to be gaining favor is the SQLite3-WinRT library on GitHub.  I have not personally used this, but seen a lot of people using this.  It allows you to use the JavaScript programming model in a familiar way:

   1: var dbPath = Windows.Storage.ApplicationData.current.localFolder.path + '\\db.sqlite';
   2: SQLite3JS.openAsync(dbPath)
   3:   .then(function (db) {
   4:     return db.runAsync('CREATE TABLE Item (name TEXT, price REAL, id INT PRIMARY KEY)');
   5:   })
   6:   .then(function (db) {
   7:     return db.runAsync('INSERT INTO Item (name, price, id) VALUES (?, ?, ?)', ['Mango', 4.6, 123]);
   8:   })
   9:   .then(function (db) {
  10:     return db.eachAsync('SELECT * FROM Item', function (row) {
  11:       console.log('Get a ' + row.name + ' for $' + row.price);
  12:     });
  13:   })
  14:   .then(function (db) {
  15:     db.close();
  16:   });

If using JavaScript this might be the way to go for your app.

Summary

I’m very glad the SQLite team worked to get this deployment package out there.  I think for some Microsoft developers, using SQLite is fairly new and this SDK package will make it easier to ensure you have the right bits at the right time.  Of course you are free to do it your own way, but I think this will ease the process a little bit.

Why no NuGet? Well, the NuGet infrastructure right now doesn’t support some of these semantics around native components to deal with headers, linking and architecture-specific deployments.  We’ll continue to work with them to see if we can drive these changes into that platform.

So please feel free to download via the Visual Studio ‘Extensions and Updates’ option from within VS, download directly from the Visual Studio Gallery, or download from the SQLite site themselves.  Once installed, once an update is available, VS will notify you that an update is available and you can install it.

Hope this helps!

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It looks like people are really glad about being able to use SQLite within their Metro style apps.  I had written two previous posts (Using SQLite in your Metro style app and HOWTO: Build and include SQLite) about this topic.  I’m pleased to report that since those posts the SQLite team released a build (3.7.13 as of the datestamp on this post) which also provides the binary (32- and 64-bit versions) pre-compiled for you for inclusion in your Metro style app.  You can get them from the SQLite download page.

I’ve received a few comments/questions that I thought I might clarify in my own opinion (and some facts) about using SQLite in your app.

Creating new databases

The first thing to understand is that your app lives in a secure sandbox during operation.  This is also referred to as the AppContainer in the Metro style app world.  What this means is that you can only do certain operations in certain places or through brokers provided by the various WinRT APIs.  The first stumbling block I’ve seen people try to do is create a database in places where they cannot create databases.  When using SQLite, regardless of whatever client method you use to program with it, you need to pass in a full path to where the database should be created (or an existing one that you are opening).  Simply passing “foo.db” in the open method is not enough as that will assume an incorrect path to create the database file.  Another incorrect thing that folks are doing is using the Windows.ApplicationModel.Package.Current.InstalledLocation.Path API.  This represents the location of where your app is installed which is not an area you can directly write files/content.

NOTE: SQLite uses the CreateFile2 API which is not a WinRT broker API.  This means that it is restricted to certain areas of the AppContainer.

The other area where people are trying to create files is in the document library location for the user.  If you have declared the Document Library capability as well as provided a file association for the file you want to create, then you can read/write files in the Document Library using the WinRT broker APIs.  This, however, is not possible using the CreateFile2 Win32 APIs. 

This leaves the app’s ApplicationData location.  So the correct path to create your database from your app is Windows.Storage.ApplicationData.Current.LocalFolder.Path as a starting point.  Here’s an example (using the sqlite-net library and C#):

   1: using (var db = new SQLiteConnection(Path.Combine(Windows.Storage.ApplicationData.Current.LocalFolder.Path, "foo.db")))
   2: {
   3:     // do stuff here
   4: }

Now whenever I need to query this database I would use that same path from my app.

Seeding your app with starting data

Some folks want to start their application with some seed data.  There are a few ways that you could do this.  One way would be to create a database during startup and execute SQL statements against the newly-created database.  You would basically be shipping a script in your app that you’d run on the first run of the app after install.  If you went this route, then you’d use the method above to create the database and then execute your INSERT statements.

Another method is to use an existing database file that perhaps you’ve already created.  The misconception here that people have is that since they include a seed database in their app that they can just open that database file and read/write on it.  The read part is correct, however you will fail to write to that file as it is in the package install location and not the ApplicationData location.  The first step you want to do in this approach is move your seed database to the place where you can write to it.  You can use the Windows.Storage APIs to accomplish this.  Here’s an example of how you might do this.  This assumes that your app has a file named “Northwind.sqlite” in your package:

   1: // grab the file from the package installed location into a StorageFile
   2: StorageFile seedFile = await StorageFile.GetFileFromPathAsync(
   3:     Path.Combine(Windows.ApplicationModel.Package.Current.InstalledLocation.Path,
   4:     "Northwind.sqlite"));
   5:  
   6: // copy the StorageFile to the ApplicationData folder
   7: await seedFile.CopyAsync(Windows.Storage.ApplicationData.Current.LocalFolder);

Now the code above does the copy.  Of course you would want to add some logic to verify that you aren’t overwriting an existing database.  Just like anything else there are various ways to do this so I am not prescribing any one way.  Once you get the data where you need it to be, then you can work with the database how you’d like.

I hope this helps understand the method of creating (in the right place) and seeding your app with a SQLite database.  Hope this helps!

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I got a few questions and comments about how to actually include SQLite in a C# Metro style app.  Since perhaps it wasn’t clear in describing in my post, I thought a quick video might help demonstrate the steps to build and use SQLite in a C# Metro style app.

The video walks through actually building SQLite from the source (Visual Studio 2012 required…express is fine) and adding it to a C# Metro style app, create a database, populate with some data based on a class and databind the query to a ListView.  The video references my OneNote notebook on the tools you need to download and build the SQLite source.  It also demonstrates using the sqlite-net library from NuGet on interacting with SQLite in a C# application.

This is a quick video to demonstrate the concept on how to get started and is not a full end-to-end sample.

NOTE: This video only demonstrates how to build SQLite until the team itself merges the WinRT changes and produces the supported build.  Until then this is a step you’d have to do on your own and these private branches are not fully supported by them until merged to their main release branch.

I hope this helps clarify things!

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At the “Developing Windows 8 Metro style apps with C++” event that happened on 18-May-2012, we saw and heard some very interesting things.  If you were watching live then hopefully you didn’t see how I tried to work through my presentation while my disk was suspiciously guzzling every last byte until it eventually ran out of space!  But I digress…

During the keynote presentation by Herb Sutter, we brought up several customers that are well-known in the native code world to talk about their experiences with Metro style apps and C++/Cx.  In particular hopefully this one caught your eye:

SQLite case study slide

That’s right, the team for SQLite was there to discuss how they were able to take their existing Win32 codebase and ensure that it worked well on Windows 8 as well as for Metro style apps.

SQLite is a in-process library that implements a self-contained, serverless, zero-configuration, transactional SQL database engine. The code for SQLite is in the public domain and is thus free for use for any purpose, commercial or private. SQLite is currently found in more applications than we can count, including several high-profile projects.

SQLite is an embedded SQL database engine. Unlike most other SQL databases, SQLite does not have a separate server process. SQLite reads and writes directly to ordinary disk files. A complete SQL database with multiple tables, indices, triggers, and views, is contained in a single disk file. The database file format is cross-platform - you can freely copy a database between 32-bit and 64-bit systems or between big-endian and little-endian architectures. These features make SQLite a popular choice as an Application File Format. Think of SQLite not as a replacement for Oracle but as a replacement for fopen().– Source: http://www.sqlite.org/about.html

Dr. Richard Hipp, the founder of SQLite, was on hand to announce the availability of the experimental branch they’ve been working on as well as that when the Release Preview of Windows 8 is made public that he will merge this code to the main trunk for SQLite, making it supported by them.  This is a really great thing for developers as SQLite has been a proven embedded database for numerous platforms and many, many customers.  The team prides themselves on testing and has millions of test cases that are validated each release.

As a Windows (and perhaps more specifically .NET) developer, you may not have had to build any lib from Open Source before of this type (i.e., native code) and since a binary is not being provided yet until Release Preview for Windows 8, I thought I’d share my tips on building the experimental bits, adding them to your projects and then using them with a client library.

UPDATE: I created a HOWTO video demonstrating the following steps of building and using from a C# Metro style app.

Building SQLite from source

If you are looking for the sqlite3.dll with this WinRT support anywhere on the sqlite.org site, you won’t find it.  You will have to build the source yourself. UPDATE:Since the origination of this post the SQLite team has released a version already compiled for 32/64-bit.  I highly recommend you get the code from the source rather than from any third party site.  Microsoft has worked with the team at SQLite to ensure compatibility and store certification.  For most .NET developers who have never grabbed native code source from an Open Source project and had to build it before, the maze of knowing what you should do can be confusing.  I’ve put together a cheat sheet on building SQLite from source for a Windows (and .NET developer) and put it on my SkyDrive: Building SQLite from source.  The OneNote I have has the details you need for the tools that will be required. 

In a nutshell you’ll need:

  • Visual Studio (easiest way to get the C++ compiler)
  • ActiveTcl
  • Update for gawk.exe
  • Fossil (the source control system used by SQLite)

Once you have these, you are ready to build SQLite.  Again, I’ll defer to my instructions on the details of setup.  Once your setup is complete, from a developer command prompt you’d run:

   1: nmake -f Makefile.msc sqlite3.dll FOR_WINRT=1

The result of this will give you basically 4 files that are of likely most importance to you: sqlite3.c, sqlite3.h, sqlite3.dll, sqlite3.pdb.

NOTE: The resulting pdb/dll that is built will be architecture specific.  If you used an x86 command prompt then that is what you have.  Be aware of this (as noted later in this post).

At a minimum you’ll want sqlite3.dll if you are a .NET developer, but as a native code developer you will likely be more interested in the others as well.  After this step, you now have a Windows Store compliant version of SQLite to include in your applications.

Runtime versus client access

Now at this point is where I’ve seen some confusion.  Folks are asking How do I include this, don’t I need a WinMD file to reference?  Let me diverge a bit and explain a few things.

The result of compiling the binary above produces primarily one thing…which I will call the “Engine” in this post.  This is the SQLite runtime and logic required to create/interact with SQLite database files.  This is NOT, however, an access library, which I will call the “Client” in this post.  If you are a managed code or JavaScript developer, at this point, all you have is the Engine, the database runtime.  You have no Client to access it.

Now, if you are a C++ developer you are probably okay at this point and don’t care much about what I have to say.  You have the header and are likely saying I’ve got the header, get out of my way.  And that is okay.  For C++ developers I think you’ll likely be accessing the database more directly through the SQLite APIs provided in the header.

I call out this distinction because this step provides you with the database engine you need to create a database and have it be store-compliant.  So if you are a JavaScript or .NET developer, what are you to do?  Stay tuned…let’s first get the Engine included in our app package.

Including SQLite in your app package

As I noted above, as a native code developer, having the header, lib and c file you may be okay and don’t care to read this.  I  personally think, however that I’d always just want the binary from my vendor rather than always include source in my files.  That said, the SQLite build process does product the amalgamation (sqlite3.c) you can just include in your native code app.

If you choose to go the binary file route (sqlite3.dll) then you need to simply follow a few principles to ensure that it is included in your package when you build your app/package.  These principles are simple:

  • include the architecture-specific binary
  • ensure the sqlite3.dll is marked as Content in your project
  • ensure you note that you now have a native code dependency (not needed if you are already a C++ Metro style app)

These two items will ensure that when you build (even for debug via F5) or when you package for the store, that the Engine is included in your package.  Marking as content is simply ensuring that after you add the file to your project, ensure the file properties note that it is content.  In .NET apps this is making the Build Action property Content.  In JavaScript applications ensure the Package Action is marked Content.

Declaring the native code dependency means you simply add a reference to the Microsoft C++ Runtime Library via the Add Reference mechanisms in .NET and JavaScript applications.  By doing this (and again, this is a requirement of including SQLite in your app) you now cannot be architecture-neutral. This means no more AnyCPU for .NET.  When producing a package you’ll have to produce architecture-specific packages before uploading to the store.  Not to worry though as Visual Studio makes this incredibly easy.  The one thing you’ll have to remember though is that you’ll have to change the sqlite3.dll before building the packages as the DLL is architecture-specific itself.

Now this all should be easier right?  Wouldn’t it be nice if you could just Add Reference to the Engine?  I personally think so.  I’ll be working with the SQLite team to see if they will adopt this method to make it as easy as this:

SQLite Extension SDK

In doing so, you as a developer would just add a reference to the Engine and then during build time Visual Studio (well MSBuild actually) will do all the right things in picking up the architecture-specific binary for your app.  No fiddling on your part.  This method also makes it easier for C++ developers as well as a props file would automatically be merged to include the .lib for linking and the header file for development.  This method uses the Visual Studio Extension SDK mechanism that was introduced in Visual Studio 11.

NOTE: Again note that as a managed (.NET) app I’d also have to ensure that my package includes the Microsoft C++ Runtime package in order for this to work and pass store certification.

Native code developers may scoff at this approach, but I could get started in 2 steps: Add Reference, #include.  No tweaking of my project files at all because the Extension SDK mechanism in VS does all this for me behind the scenes.

So why don’t I just give you the VSIX to install and accomplish the above?  Well simply, because SQLite is not my product and we’ve had a good relationship with their team and I want to make sure they understand the benefits of this method before jumping right in.  I hope that they will like it as I think it makes it *really* simple for developers.

Accessing the Engine from your app

Great, you’ve compiled the bits, you’ve understood how to ensure sqlite3.dll gets packaged in your application…now how do you use it!!!  Here’s the assessment of where we are at for Metro style apps as of the writing of this post.

C++ app developers: I think most C++ developers will get the header file (sqlite3.h) and be okay on their own with SQLite.  At this stage for them there doesn’t appear to be a real huge benefit of a WinRT wrapper to use the Engine.

.NET developers: I’ve messed around with a few libraries and believe the sqlite-net project to be the most favorable for what I believe most use cases will be for SQLite and Metro style apps.  This is a .NET-only library (not WinRT) but is basically a “LINQ to SQLite” approach.  The Mono team uses this one as well.  The necessary .NET 4.5 Core changes are already included in the project on github.  So you just need to get the SQLite.cs file and include it in your project.  Using this library allows you to write code like this:

   1: public sealed partial class BlankPage : Page
   2: {
   3:     public BlankPage()
   4:     {
   5:         this.InitializeComponent();
   6:  
   7:         string dbRootPath = Windows.Storage.ApplicationData.Current.LocalFolder.Path;
   8:         using (SQLiteConnection db = new SQLiteConnection(Path.Combine(dbRootPath, "mypeople.sqlite")))
   9:         {
  10:             db.CreateTable<Person>();
  11:  
  12:             db.RunInTransaction(() =>
  13:                 {
  14:                     for (int i = 0; i < 10; i++)
  15:                     {
  16:                         db.Insert(new Person() { FullName = "Person " + i.ToString() });
  17:                     }
  18:                 });
  19:         }
  20:     }
  21: }
  22:  
  23: public class Person
  24: {
  25:     [AutoIncrement, PrimaryKey]
  26:     public int ID { get; set; }
  27:     public string FullName { get; set; }
  28:     public string EmailAddress { get; set; }
  29:     public double Salary { get; set; }
  30: }

This is clearly just a sample, but demonstrates the simplicity of the library. 

NOTE: In the snippet above you do want to make sure you are creating your database in a path that is accessible from the AppContainer.  The best place is in the app’s ApplicationData location.  When specifying a path to SQLite in Open() for creation, give an explicit path always to ensure you aren’t relying on a temp file creation.

Some may ask about System.Data.Sqlite and this cannot be used because of the dependency of ADO.NET which is not a part of the .NET Framework Core profile.

Now this leads us to JavaScript developers.  Currently, there is not easy way for you to access this.  The Developer and Platform Evangelism team are working on some samples that are not quite complete yet.  JavaScript developers will need a WinRT library in order to access/create/query the Engine.  There are some out there (I haven’t played around with any of these) that would be good to see if they meet your needs.  Here are some pointers:

At the C++ event we talked with the SQLite team about a WinRT client library and will continue to talk with them to see if this is something of interest.  SQLite has a great history of working with the community and have a desire to continue this.  In the meantime, there are options for you to get started.  Also note, that since these are WinRT libraries they could also be used from C++ and .NET in Metro style apps.  At this point though it is my personal opinion that existing .NET libraries for .NET offer more value (i.e. LINQ) than how these WinRT ones exist.

Summary

This was a great announcement that the SQLite team made for Metro style app developers.  WinRT provides some existing local storage mechanisms which you should explore as well, however none that have structured storage with a query processor on top of it.  I’m really glad that the SQLite team was able to make a few diff’s to their code to accommodate a few store compliance areas and continue to offer their great product to this new class of applications.  It is very simple to get started by ensuring you have the Engine and picking your Client of your choice and write your app using SQLite for some local/structured storage!

Hope this helps and stay tuned for the release preview of Windows 8!