<title>Frequently Asked Questions</title>
<a name="faq"></a>
<h2>Frequently Asked Questions</h2>
<ol>
<li>
<a href="#q1">When will the <b>next version</b> of System.Data.SQLite be
released?</a>
</li>
<br>
<li>
<a href="#q2">When are you planning on adding feature "X"?</a>
</li>
<br>
<li>
<a href="#q3">What versions of <b>.NET Framework</b> are supported?</a>
</li>
<br>
<li>
<a href="#q4">What versions of <b>Visual Studio</b> are supported?</a>
</li>
<br>
<li>
<a href="#q5">Is there a <b>NuGet</b> package?</a>
</li>
<br>
<li>
<a href="#q6">How do I build the binaries for <b>Mono</b>?</a>
</li>
<br>
<li>
<a href="#q7">How do I build the binaries for <b>.NET Compact Framework</b>?</a>
</li>
<br>
<li>
<a href="#q8">How do I install System.Data.SQLite on a <b>development
machine</b>?</a>
</li>
<br>
<li>
<a href="#q9">How do I install System.Data.SQLite on <b>end-user
machines</b>?</a>
</li>
<br>
<li>
<a href="#q10">Do I need to add an assembly reference to the
"<b>sqlite3.dll</b>" or "<b>SQLite.Interop.dll</b>" in
my project?</a>
</li>
<br>
<li>
<a href="#q11">Why do I get a <b>DllNotFoundException</b> (for
"sqlite3.dll" or "SQLite.Interop.dll") when trying to
run my application?</a>
</li>
<br>
<li>
<a href="#q12">Why do I get a <b>BadImageFormatException</b> (for
"sqlite3.dll" or "SQLite.Interop.dll") when trying to
run my application?</a>
</li>
<br>
<li>
<a href="#q13">Why do I get the error "<b>This assembly is built by a
runtime newer than the currently loaded runtime and cannot be loaded.</b>
"?</a>
</li>
<br>
<li>
<a href="#q14">What is a <b>mixed-mode assembly</b>?</a>
</li>
<br>
<li>
<a href="#q15">What is a "<b>bundle</b>" package (i.e. from the
download page)?</a>
</li>
<br>
<li>
<a href="#q16">What is the difference between the "<b>Setup</b>"
and "<b>Precompiled Binary</b>" packages (i.e. from the download
page)?</a>
</li>
<br>
<li>
<a href="#q17">Why is System.Data.SQLite <b>leaking</b> memory, resources,
etc?</a>
</li>
<br>
<li>
<a href="#q18">What are the <b>support options</b> for System.Data.SQLite?</a>
</li>
<br>
<li>
<a href="#q19">When the solution is loaded in Visual Studio, why do no files
show up for several of the projects in the <b>Solution Explorer</b> window?
</a>
</li>
<br>
<li>
<a href="#q20">When the System.Data.SQLite project is compiled and run from
inside Visual Studio, why do I get a <b>DllNotFoundException</b> or a
<b>BadImageFormatException</b> (for "sqlite3.dll" or
"SQLite.Interop.dll") when trying to run or debug the application?
</a>
</li>
</ol>
<hr>
<a name="q1"></a>
<p>
<b>(1) When will the next version of System.Data.SQLite be released?</b>
</p>
<p>
The release schedule for the System.Data.SQLite project is roughly
synchronized (within about two or three weeks) with that of the
[http://www.sqlite.org/ | SQLite] core itself. The release history for the
System.Data.SQLite project is [./news.wiki | here].
</p>
<hr>
<a name="q2"></a>
<p>
<b>(2) When are you planning on adding feature "X"?</b>
</p>
<p>
This question is hard to answer precisely. It depends on a number of factors,
including but not limited to:
<ul>
<li>
Can the feature be implemented in a backward compatible manner?
</li>
<li>
Can the feature be implemented in a portable fashion for all the currently
supported versions of the .NET Framework and/or Visual Studio?
</li>
<li>
Does the feature fit well with the current design of the project?
</li>
<li>
How much time will it take to design, implement, and test the feature?
</li>
<li>
Will the feature benefit the entire community or only a tiny subset
thereof?
</li>
</ul>
</p>
<hr>
<a name="q3"></a>
<p>
<b>(3) What versions of .NET Framework are supported?</b>
</p>
<p>
<ul>
<li>
The .NET Framework 2.0 SP2 (or higher) for the System.Data.SQLite assembly.
</li>
<li>
The .NET Framework 3.5 SP1 (or higher) for the System.Data.SQLite.Linq
assembly.
</li>
<li>
All sub-projects are fully supported with the .NET Framework 4.0.
</li>
<li>
All sub-projects are fully supported with the .NET Framework 4.5.
</li>
</ul>
</p>
<hr>
<a name="q4"></a>
<p>
<b>(4) What versions of Visual Studio are supported?</b>
</p>
<p>
Currently, Visual Studio 2005, 2008, 2010, and 2012 are supported, including
the "Express" editions; however, in order to build the entire
solution, including the necessary native code, the "Professional"
edition (or higher) is required. It may be possible to install both Visual C#
Express and Visual C++ Express and then build the corresponding sub-projects
via their respective integrated development environments (IDE); however, this
configuration has <b>not</b> been tested. The design-time components are
<b>no longer</b> supported for the Express editions due to licensing
restrictions.
</p>
<hr>
<a name="q5"></a>
<p>
<b>(5) Is there a NuGet package?</b>
</p>
<p>
Yes, the following official NuGet packages are available:
<ul>
<li>
<a href="http://www.nuget.org/packages/System.Data.SQLite">
System.Data.SQLite</a>: The SQLite database engine for both x86 and x64
along with the ADO.NET provider.
</li>
<li>
<a href="http://www.nuget.org/packages/System.Data.SQLite.x86">
System.Data.SQLite.x86</a>: The SQLite database engine combined with a
complete ADO.NET provider all rolled into a single mixed-mode assembly for
x86.
</li>
<li>
<a href="http://www.nuget.org/packages/System.Data.SQLite.x64">
System.Data.SQLite.x64</a>: The SQLite database engine combined with a
complete ADO.NET provider all rolled into a single mixed-mode assembly for
x64.
</li>
<li>
<a href="http://www.nuget.org/packages/System.Data.SQLite.MSIL">
System.Data.SQLite.MSIL</a>: Just the ADO.NET provider for SQLite
(managed-only).
</li>
</ul>
</p>
<hr>
<a name="q6"></a>
<p>
<b>(6) How do I build the binaries for Mono?</b>
</p>
<p>
This is documented on the [./build.wiki#mono | build procedures] page.
</p>
<hr>
<a name="q7"></a>
<p>
<b>(7) How do I build the binaries for .NET Compact Framework?</b>
</p>
<p>
This is documented on the [./release.wiki#buildCeBinaries | release procedures]
page.
</p>
<hr>
<a name="q8"></a>
<p>
<b>(8) How do I install System.Data.SQLite on a development machine?</b>
</p>
<p>
Strictly speaking, there is no need to install System.Data.SQLite on any
development machine (e.g. via the setup). The recommended way to use the
assemblies is:
<ul>
<li>
Download the precompiled binary package for your target framework and
processor architecture (e.g. 32-bit x86, .NET Framework 2.0).
</li>
<li>
Extract the package to a directory named "Externals" inside your project
directory.
</li>
<li>
Add a reference to the "System.Data.SQLite" assembly from the "Externals"
directory.
</li>
<li>
If necessary (i.e. you require LINQ support), also add a reference to the
"System.Data.SQLite.Linq" assembly from the "Externals" directory.
</li>
</ul>
</p>
<p>
Alternatively, when using Visual Studio 2010 or later, you can simply use the
NuGet package that corresponds to your target processor architecture.
Installing the assemblies into the Global Assembly Cache is not recommended as
it may cause conflicts with other applications installed on the machine.
</p>
<hr>
<a name="q9"></a>
<p>
<b>(9) How do I install System.Data.SQLite on end-user machines?</b>
</p>
<p>
Strictly speaking, there is no need to install System.Data.SQLite on any
end-user machine (e.g. via the setup). The recommended way to deploy the
assemblies is "application local" (i.e. copy them to the directory
the application is installed to). Installing the assemblies into the Global
Assembly Cache is not recommended as it may cause conflicts with other
applications installed on the machine.
</p>
<hr>
<a name="q10"></a>
<p>
<b>(10) Do I need to add an assembly reference to the
"sqlite3.dll" or "SQLite.Interop.dll" in my project?</b>
</p>
<p>
No, because they are not managed assemblies and contain no managed code.
</p>
<hr>
<a name="q11"></a>
<p>
<b>(11) Why do I get a <b>DllNotFoundException</b> (for "sqlite3.dll"
or "SQLite.Interop.dll") when trying to run my application?</b>
</p>
<p>
Either the named dynamic link library (DLL) cannot be located or it cannot be
loaded due to missing dependencies. Make sure the named dynamic link library
is located in the application directory or a directory along the system PATH
and try again. Also, be sure the necessary Visual C++ runtime redistributable
has been installed unless you are using a dynamic link library that was built
statically linked to it.
</p>
<hr>
<a name="q12"></a>
<p>
<b>(12) Why do I get a BadImageFormatException (for "sqlite3.dll" or
"SQLite.Interop.dll") when trying to run my application?</b>
</p>
<p>
The named dynamic link library (DLL) contains native code that was built for a
processor architecture that is not compatible with the current process (e.g.
you cannot load a 32-bit dynamic link library into a 64-bit process or
vice-versa). Another explanation is that the named dynamic link library was
built for a later version of the CLR than is available in the current process
(e.g. you cannot load an assembly built for the .NET Framework 4.0 into a .NET
Framework 2.0 process, regardless of the processor architecture).
</p>
<hr>
<a name="q13"></a>
<p>
<b>(13) Why do I get the error "This assembly is built by a runtime newer
than the currently loaded runtime and cannot be loaded."?</b>
</p>
<p>
Because the assembly was built for the .NET Framework 4.0 and you are trying
to load it into a process that is using the .NET Framework 2.0.
</p>
<hr>
<a name="q14"></a>
<p>
<b>(14) What is a mixed-mode assembly?</b>
</p>
<p>
A mixed-mode assembly is a dynamic link library that contains both managed
code and native code for a particular processor architecture. Since it
contains native code it can only be loaded into a process that matches the
processor architecture it was compiled for. Also see this
<a href="http://stackoverflow.com/questions/7266936/what-is-a-mixed-mode-assembly">StackOverflow question</a>.
</p>
<hr>
<a name="q15"></a>
<p>
<b>(15) What is a "bundle" package (i.e. from the download page)?</b>
</p>
<p>
The "bundle" packages listed on the download page contains the
System.Data.SQLite mixed-mode assembly in a file named
"System.Data.SQLite.dll" (see <a href="#q14">question #14</a>)
instead of separate "System.Data.SQLite.dll" and
"SQLite.Interop.dll" files to contain the managed code and native
code, respectively.
</p>
<hr>
<a name="q16"></a>
<p>
<b>(16) What is the difference between the "Setup" and
"Precompiled Binary" packages (i.e. from the download page)?</b>
</p>
<p>
The "Setup" packages are designed to install the necessary files,
optionally installing the assemblies into the Global Assembly Cache,
generating native images for the managed assemblies via Ngen, adding Start
Menu shortcuts, modifying the .NET Framework machine configuration files to
register the ADO.NET provider, and installing the design-time components for
Visual Studio. The "Precompiled Binary" packages are simply ZIP
files that contain all the binaries compiled for a particular .NET Framework
and processor architecture.
</p>
<hr>
<a name="q17"></a>
<p>
<b>(17) Why is System.Data.SQLite leaking memory, resources, etc?</b>
</p>
<p>
All System.Data.SQLite objects that implement IDisposable, either directly or
indirectly, should be explicitly disposed when they are no longer needed. If
this is the case and you are still seeing a leak of some kind, please file a
<a href="/index.html/tktnew">ticket</a>.
</p>
<hr>
<a name="q18"></a>
<p>
<b>(18) What are the support options for System.Data.SQLite?</b>
</p>
<p>
This is discussed on the [./support.wiki | support] page.
</p>
<hr>
<a name="q19"></a>
<p>
<b>(19) When the solution is loaded in Visual Studio, why do no files show up
for several of the projects in the Solution Explorer window?</b>
</p>
<p>
Several of the sub-projects (i.e. primarily those that build variants of the
System.Data.SQLite assembly) share an MSBuild "targets" file that
contains the actual references to the C# source code files. Unfortunately,
due to limitations on how Visual Studio reads and interprets MSBuild files at
design-time, the C# source code files do not show up in the Solution Explorer
window. This limitation is largely cosmetic and does <b>not</b> impact the
correctness of the build process itself, whether in Visual Studio or when
using MSBuild on the command line.
</p>
<hr>
<a name="q20"></a>
<p>
<b>(20) When the System.Data.SQLite project is compiled and run from inside
Visual Studio, why do I get a DllNotFoundException or a BadImageFormatException
(for "sqlite3.dll" or "SQLite.Interop.dll") when trying to
run or debug the application?</b>
</p>
<p>
When compiling and running a solution from within Visual Studio that uses the
System.Data.SQLite project (including the test project), it is very important
to select the correct build configuration and platform. First, managed
applications to be debugged inside Visual Studio cannot use the mixed-mode
assembly (i.e. because it is always compiled to the platform-specific build
output directory). This is necessary to properly support building binaries
for multiple platforms using the same source project files. Therefore, only
the "DebugNativeOnly" or "ReleaseNativeOnly" build
configurations should be selected when running a managed application from
inside Visual Studio that relies upon the System.Data.SQLite assembly. These
build configurations contain a custom post-build step that copies the required
native assembly to the managed output directory (i.e. to enable running the
managed binaries in-place). However, this post-build step will only be
performed if the selected platform matches that of the operating system (e.g.
"Win32" for 32-bit Windows and "x64" for 64-bit Windows).
Therefore, it is good practice to double-check the selected build platform
against the operating system prior to attempting to run a managed project in
the solution.
</p>
