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Trying to understand Microsoft.Data.dll

Here is my analysis of the recently “released” (embedded) Microsoft.Data.dll assembly, the namespace and the types it includes. It’s been the topic of a lot of heated debate recently, with viewpoints I’m unable to relate to and understand just from reading, so I needed to understand.

The debate is stemming from a blog post by David Fowler and his example that shows how some data-related tasks have a simpler syntax with Microsoft.Data and the ASP.NET WebPages with Razor Syntax.

What is inside the Microsoft.Data namespace?

There is very little code inside the namespace and the assembly. It’s simply some helper types that makes life's a little bit easier. It’s not a new data access framework, like Linq to SQL or Entity Framework.

It contains the following classes: ConfigurationManagerWrapper, ConfigurationConfiguration, Database, DbProviderFactoryWrapper, DynamicRecord, IConfigurationManager, IDbFileHandler, IDbProviderFactory, SqlCeDBFileHandler and SqlServerDbFileHandler. Of which only Database and DynamicRecord are public available, the others are internal.

All data access inside the Microsoft.Data types are using the common ADO.NET types, not the providers specific for any SQL platform. This means it’s not restricted to SQL Compact Edition nor SQL Server. It relies on DbConnection, DbTransaction, DataTable, etc.

Microsoft.Data on ASP.NET Web Forms

While Microsoft.Data.dll is currently not accessible in the Add References dialog, you can find it by looking on your computer, it’s located in the Global Assembly Cache (GAC). Microsoft probably don’t want us to use it outside of WebMatrix in the current release… but if you just take a copy of the assembly out of the GAC, then you can reference the assembly in any .NET project and it will load it from the GAC (you just need the file so you can add a reference).

In my project I added a database to my App_Data folder (which you normally would never do, unless you are working with a local read-only cache in a large-distributed system or working with SQL Compact Edition) and added the following code to my web form, to make it render the Name column of my Users table.

	var db = Database.OpenFile("Database1.mdf");
	var users = db.Query("SELECT Id, Name FROM Users");
	foreach (var user in users)
	{
	Response.Write(user["Name"]);
	}
	

Take notice of the OpenFile parameter, it’s simply the filename on disk. I don’t have to care about any specific details of the connection string, nor how to figure out where the App_Data folder is.

Obviously though, if you added an entity framework (EF) model of your database, you would have very similar example to achieve the same and you don’t have to care about the connection string, at least not in theory.

	using (var db = new Database1Entities())
	{
	var users = db.Users;
	foreach (var user in users)
	{
	Response.Write(user.Name);
	}
	}
	

The two big distinctions betweens these examples is that the first one is dynamic, I can modify the database schema whenever I want and it won’t (necessarily) break my web app, while the latter example with EF will need to refresh the entity types based on the database model.

The other distinctions is that the first example doesn’t require a connection string, while the latter generates one for you automatically, a rather cryptic looking one.

<add name="Database1Entities" connectionString="metadata=
res://*/Model1.csdl|
res://*/Model1.ssdl|
res://*/Model1.msl;
provider=System.Data.SqlClient;
provider connection string=&quot;
Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\Database1.mdf;
Integrated Security=True;
User Instance=True;
MultipleActiveResultSets=True&quot;" providerName="System.Data.EntityClient" />

 

While all of this are peanuts for me and anyone who’s been developing on .NET for a while, I think that making things simple where possible is positive, rather than negative. It doesn’t mean we will stop using NHibernate, do proper n-tier and layered architectures just because Microsoft makes some tasks simpler for beginners. It also means some of us probably will eventually have to maintain and possibly migrate solutions built on Microsoft WebMatrix, but does that give us any right to restrict beginners the privilege of building their own solutions and feeling the immense joy of realizing their dreams?

Other’s feedback and comments

Ayende Rahien comments on his blog on the example, where he mentions the use Response.Write within the loop. Understandable this is probably not the best way to do this, but it’s understandable with the sample in question, which was already using Response.Write. There are slightly better examples available out there. He also points out that having the SQL queries directly in the view code is an open invitation for SQL injection. Using proper parameterized queries will reduce this potential security problem. Looks like David updated the sample to use parameters after the initial reactions. After the security push at Microsoft some years back, they really cleaned up their practices with examples in the MSDN documentations, I think we should expect the same level of security thinking on employee blogs as well.

Ayende quotes David, which (David) made the assumption that Microsoft.Data is tied to Sql Server in any way, which my investigations has shown is not correct.

David tried to respond to some of the feedback on embedding SQL directly in the view, with hacking around to get the new dynamic keyword to work properly with LINQ. To me, this defeats the whole purpose of simplicity with Microsoft WebMatrix, Razor and Microsoft.Data.

KristoferA comments on the post and suggests generating Linq to SQL datacontext using a page-level directive, which would essentially give the developer entity objects to work with (and query against). This again defeats the purpose of simplicity, and now you can no longer change the database scheme without “recompiling” your web-app.

The namespace naming is another sour point for some, and I can agree that there is little point is “abusing” the Microsoft.Data namespace for such a trivial little helper, perhaps Microsoft.WebMatrix.Data or Microsoft.Data.Connection?

Who is this for?

Microsoft WebMatrix (and ASP.NET WebPages) is not a tool built for “professional” programmers, additionally is it not a fully generic framework for building everything. It’s a domain specific language that is optimized for building simple web applications without to much resources.

It is not meant for enterprise applications that handles millions of transactions. Will it be used for that? Yes, it probably will! We’ve seen plenty of classic examples of websites that starts with simple web-frameworks and find themselves in big trouble when their services become popular. Services like Twitter and Facebook was not built to scale to their current levels, yet they started as simple concepts and services and has grown to become important services which affects global policies and real-life social interactions.

It's Not Rocket Science, But It's Our Work: http://blog.twitter.com/2008/05/its-not-rocket-science-but-its-our-work.html

And obviously, it’s for those of us who still miss the old days with ASP Classic, here is a pretty good (and funny) read, 8 Reasons to Stick with ASP 3.0 in 2006 (and 2007).

Final thoughts

It’s very clear that Microsoft WebMatrix (and related technologies) are primarily is focused towards beginners and it’s a great tool to build simple websites. I wouldn’t advice anyone to use this if you already know ASP.NET MVC and want to build complex web solutions, ASP.NET Web Forms, MVC or other more general purpose frameworks would probably be more fit.

Additionally I think it’s important to remember that WebMatrix is primarily focused on SQL Compact Edition for data access, the built in editor doesn’t allow you to modify SQL Server database. So the question (and response to some of the comments) is how many layers do you want to wrap your data access logic for a SQLCE database?

Been a while since Microsoft did a push towards simplifying development for beginners, when we went from VB6 to VB.NET, everything was more complex and the entry level for VB.NET is on-par with C#. With the release of .NET Framework 4, the complexity and total amount of features is mind blowing. I for sure welcome tools, languages and frameworks that simplifies how we develop software.

Simplicity is hard and it's something we should strive towards in all that we do.

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