"Steven Wilmot" <steven-n***@wilmot.me.uk> wrote in message
news:OyfVj7J6FHA.2552@TK2MSFTNGP10.phx.gbl...
> I've recently started to convert an old VS2003 project that was using some
> SQL2000
>
> I now want to convert this project to VS2005
>
> I've currently referenced:
>       D:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.Data.dll
> (Version = 2.0.0.0)
> AND:
>       D:\Program Files\Microsoft Visual Studio
> 8\Common7\IDE\PublicAssemblies\System.Data.SqlClient.dll (Version =
> 3.0.3600.0)
>
> The question is: which one should I be using, and why does System.Data
> ALSO contain a definition for SQLConnection
>
> (Currently I get an error in my project):
>
>     An assembly with the same identity 'System.Data.SqlClient,
> Version=3.0.3600.0, Culture=neutral, PublicKeyToken=3be235df1c8d2ad3,
> Retargetable=Yes' has already been imported. Try removing one of the
> duplicate references.
>
> ---
>
> I know how to get rid of it (only reference one of the DLLs) but want to
> know WHY it is happening.
>
>
>

"Steven Wilmot" <Steven_W@newsgroups.nospam> wrote in message
news:uvOkxWU6FHA.2036@TK2MSFTNGP14.phx.gbl...
>
> "S.M. Altaf [MVP]" <smaltaf@PLEASEDONTSPAMMEmsn.com> wrote in message
> news:ulU2imS6FHA.2576@TK2MSFTNGP09.phx.gbl...
>> Simply put, System.Data is a generalized namespace for the most common
>> classes like DataSets, DataReaders, etc.  System.Data.SqlClient is the
>> namespace you'd use when working with SQL Server, specifically.  There
>> are other namespaces like System.Data.OdbcClient and OledbClient which
>> are for other databases.
>>
>> HTH
>> -Altaf
>>
>
> Unfortunately, this completely misses the point of my question.
>
> I realise what the different namespaces are fo - I am asking about the two
> assemblies
>
> D:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.Data.dll
>   This contains the namespace System.Data
>   This also contains the namespace System.Data.SqlClient
>
> D:\Program Files\Microsoft Visual Studio
> 8\Common7\IDE\PublicAssemblies\System.Data.SqlClient.dll
>   This also contains the namespace System.Data.SqlClient
>    ... But, this depends on the definition of the type
> 'System.Data.IDbConnection' , which is defined in an assembly that is not
> referenced.:
>               ( 'System.Data, Version=2.0.0.0, Culture=neutral,
> PublicKeyToken=969db8053d3322ac)
>
> However, if I then add the System.Data.Dll assembly, I am presented with
> another error.
>
>        An assembly with the same identity 'System.Data.SqlClient,
> Version=3.0.3600.0, Culture=neutral, PublicKeyToken=3be235df1c8d2ad3,
> Retargetable=Yes' has already been imported. Try removing one of the
> duplicate references. d:\Program Files\Microsoft Visual Studio
> 8\Common7\IDE\PublicAssemblies\System.Data.SqlClient.dll
> WindowsApplication2
>
> ----
>
> This makes the version of System.Data.SqlClient.DLL (v3.0.6000.0)
> incompatible with the v2.0.50727 of the .NET framework ....
>