Monday, October 27, 2014

“Database First” with SQLite in a Universal App using the SQLite Toolbox and sqlite-net

In this blog post I will describe how to use the reverse engineering feature of the SQLite Toolbox to generate code for use with the sqlite-net codebase in a Universal App. A Universal App is a special solution template, that allows you to shared code and resource assets between a Windows Phone 8.1 and Windows Store 8.1 Application, in order to minimize code duplication and increase code reuse, if your application targets both these platforms.

My fellow MVP Nicolò Carandini has a couple of great blog posts on how to get started with SQLite in a Universal App. Since he posted this, the SQLite extension SDKs have been updated and are now directly available in the Extension Manager in Visual Studio 2013, so go and install these two downloads – go to Tools, Extensions and Updates, select Online and search for “sqlite”:


Install these three extensions:
- SQLite for Windows Phone 8.1
- SQLite for Windows Runtime (Windows 8.1)
- SQL Server Compact/SQLite Toolbox

The two other SQLite extensions are for version Windows/Windows Phone 8.0. Notice that in order to use the SQLite Toolbox, currently you must have SQL Server Compact 4.0 or 3.5 installed, this will not be required in the next release. Now restart Visual Studio.

Follow the steps in Nicolo’s blog until you have the two SQLite-net files available in the .Shared “project”:


Instead of typing the table classes by hand, the SQLite Toolbox can help you generate the required classes for you based on an existing SQLite database file. You could even then include the SQLite database file with your application, for example if any of the tables contain reference data. I describe how to handle reference data in my previous blog post here.

Notice that the sqlite-net classes are not a full blown OR-M, but rather a simple SQL to class translator. It does not support for example change tracking, relationships (foreign keys), Unit of Work, multi column primary keys etc. Those features will be present and available for Universal apps in the new Entity Framework release coming beginning of 2015, EF7.

Open the SQLite Toolbox from Server Explorer or the Tools menu, and connect to an existing SQLite database. For an overview of all SQLite features in the Toolbox, see my blog post here.


Select the shared project in Solution Explorer, then right click the database and select “Add sqlite-net Model.cs to current project”


The generated code (Model.cs) contains a SQLiteDb class with a method to create all the tables in the database (if you just want to use the existing database file as a template), and class definitions for each table in the database:

    public partial class Album
[Unique(Name = "IPK_Album", Order = 0)]
public Int64 AlbumId { get; set; }

public String Title { get; set; }

[Indexed(Name = "IFK_AlbumArtistId", Order = 0)]
public Int64 ArtistId { get; set; }


As you can see, attributes like MaxLength, Index and NotNull help define the table.

Hope you find this timesaving feature and the other SQLite features in the Toolbox helpful, and please provide any feedback here.

Monday, October 20, 2014

Entity Framework 6 and SQL Server Compact 4.0 – “Proper” private desktop deployment

About a year after I published the blog post Entity Framework 6 & SQL Server Compact 4 (2)–Easy Private Desktop Deployment it has occurred to me that the solution proposed in that blog post is far from perfect – my apologies! The suggestions for location of the database file etc. are still valid points, however.

TL;DR – Use my new NuGet package for Private Desktop deployment with SQL Server Compact 4.0 and Entity Framework 6, and make sure that:
- The binding redirect is set to: oldVersion=""
- Prefer32Bit project option is disabled

The goal

First, let’s clarify what the goal behind “private desktop deployment” with SQL Server Compact is:

The goal is to be able to drop a folder of files on any PC and just run  a .NET application that includes a self-contained relational database and a sophisticated ORM over that database.

This goal is achievable with SQL Server Compact 4.0 and Entity Framework 6, as long as the PC in question has .NET Framework 4.0 installed.

The issues

First, let us look at the issues with the approach in the above blog post:
1: This approach uses the Microsoft.SqlServer.Compact package, which explicitly uses the non-private assembly version of System.Data.SqlServerCe.dll (which is And it assumes that your project targets AnyCPU. This means that if you have SQL Server Compact installed in GAC, then the version from there will be picked up. That will work fine, as long as you have the exact same build of SQL Server Compact in both GAC and your application folder. But this leads us to issue number 2!
2: The EntityFramework.SqlServerCompact package does not depend explicitly on a release version of the Microsoft.SqlServer.Compact NuGet package and will pick up build 8854, which is 4.0 SP1 CTP1, instead of build 8876, which is 4.0 SP1 proper. (I wish that the 8854 builds were no longer visible on NuGet) – I am working on a fix for this, which is planned for EF 6.1.2. So the chances of not having the same version in GAC and locally are relatively big, and this will cause an error to be thrown, preventing your app from working:
Possible file version mismatch detected between ADO.NET Provider and native binaries of SQL Server Compact which could result in an incorrect functionality.

Manual fix

If you would like to ensure that your desktop application (console, Windows Forms or WPF) app can run anywhere use proper private deployment, follow these steps (in outline):

1: Install EntityFramework.SqlServerCompact

2: Copy files from Private folder in C:\Program Files (x86) to the project folder (as described in my Private deployment with LINQ to SQL blog post)

3: Make project x86 only (or at least remove the “Prefer 32 bit” option if you include all unmanaged dll files 

4: Disable post build event (via Project Properties/Build events tab) to prevent the dll from being deployed

5: Modify app.config

a) add assembly redirect, as the EntityFramework.SqlServerCompact.dll references version, and we want to use

<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<assemblyIdentity name="System.Data.SqlServerCe" publicKeyToken="89845dcd8080cc91" culture="neutral"/>
<bindingRedirect oldVersion="" newVersion=""/>

b) With version => in DbProviderFactories section:


“Automatic” fix

I have published a NuGet package EntityFramework.SqlServerCompact.PrivateDeployment  that performs most of the actions above, specifically 1, 2 (via a clever package that performs a build step), 3 (via an additional command in install.ps1), 4, and partly 5 (for some reason NuGet generates an incorrect bindingRedirect, so it must be fixed manually). Currently in pre-release, please provide feedback!


This package includes both the EntityFramework.SqlServerCompact provider for EF 6.1.1 and the SQL Server Compact 4.0 files for private deployment. I intend to update the package with the upcoming version 6.1.2 release of Entity Framework.