Manjula's Blog : C#

SubSonic - Part 1 - An Introduction

Manjula Perera — Thu, 03 Jan 2008 06:27:00 GMT

Overview

This is another interesting article about the new trends of the software industry. I would like to share the information I gathered while researching on this new toolset with the user group members and the readers of this blog. I thought of writing about SubSonic because it's another way of accessing/ Querying the database (Actually, SubSonic is a third party toolset to auto generate the Data Access Layer (DAL) of our application and maintain it when the database changes). This is just another handy tool for us as LINQ. Therefore I'll write about SubSonic in parallel to the LINQ articles. We can compare LINQ and SubSonic later on. Since this is the first article about SubSonic in this forum I'll start with an introduction.

What is SubSonic?

SubSonic, initially named as ActionPack is developed as an open source project by Rob Conery before he joined Microsoft, but who is currently working for Microsoft in the ASP.Net team under Scott Guthrie. The other team members of this project are Eric Kemp, Scott Watermasysk, Jon Galloway, Phil Haack, and Gavin Joyce. This project has got attention from Microsoft even though it is still an open source project. SubSonic will be developed on top of ASP.Net and the new MVC framework that Microsoft has given more attention of. (This information is true at the time of writing this article and as per the SubSonic Project & Rob Conery's comments)
We can download the latest source code here
SubSonic is a toolset that helps a website build itself. It brings some of the fun and elegance of Ruby on Rails to ASP.NET
This implements Active Record design pattern.
Helps us quickly build data driven websites without writing data manipulation code
Has a DAL generator that enables us to rapidly create strongly typed collections and CRUD (Create, Read, Update and Delete) enabled objects, which represent the selected database tables
Has an object relational (OR) mapper which extends to stored procedures and views
Could also automatically generate the UI for the data manipulation tasks (scaffolding support). This is very handy when creating the admin panel of a data driven web applications. We don't need to worry about creating it from scratch
Has a dynamic query tool that let us use SQL Server, MySQL and Enterprise Library (Application Blocks) without having to know the underlying SQL syntax (Lets go into technical details in the next articles to follow)
We just need to give the reference to the SubSonic DLL and set SubSonic settings in the Web.config file to make use of the power of SubSonic (Lets go into technical details in the next articles to follow)
Saves lot of development time and that is the main objective of creating SubSonic. Will our bosses give more work for the time we save using SubSonic?

Summery

SubSonic is an open source tool set to auto generate data manipulation code and interfaces. This works on top of ASP.Net and the MVC framework. This gives an extension and a cool new addition to the strength of .Net compliance languages and most importantly this SAVES lot of development time.

Rule Of Thumb

I'm pretty sure SubSonic will not replace classic SQL, T/SQL or PL/SQL but it will extend the data manipulation capability of the programmer. IT saves lot of time. It's a pretty cool tool to be in our tool box. We as the programmers must decide when to use it and when not to.

References

LINQ - Part 2 - FAQs & Answers

Manjula Perera — Wed, 02 Jan 2008 05:42:00 GMT

Overview

I thought of listing down few Frequently Asked Questions about LINQ and their answers before proceeding to the technical details of it. This is mainly because I might have missed any introductory information regarding LINQ. Please refer to the below LINQ FAQ related web postings.

More Links to LINQ

Links to LINQ

LINQ - Part 1 - the new querying enhancement to C# and VB.Net

Manjula Perera — Sun, 30 Dec 2007 13:23:00 GMT

Overview

I thought of gathering some information about Microsoft's latest querying technology and summerising that information here so that readers of this Blog and the members of the .NetFoundry user group will benefit from it. There's lot to talk about LINQ. Therefore I'll split this article into several parts and publish separately. Since this is the first article about LINQ in the user group I'll start with an introductory and would try to give a glimps in to LINQ.

What is LINQ?

LINQ - Language INtegrated Query
Is an extension to .Net compliant languages like C#, VB.Net and others for general purpose querying
Object based, language integrated way to query over data no matter from where that data came from or generated
Is a universal querying mechanism where we can query objects, collections, text files, relational data and XML
Could retrieve data from any object that implements the IEnumerable<T> interface
Is an integral part of Visual Studio 2008 and could incorporate with Visual Studio 2005 as an additional CTP download
Used to overcome the impedance mismatch between programming languages and database
LINQ has been separated into three main areas. They are,

LINQ to Object
LINQ to ADO.Net (LINQ enabled ADO.Net)

LINQ to SQL - DLINQ
LINQ to DataSet
LINQ to Entities

LINQ to XML - XLINQ

Highly extensible

LINQ Architecture

The architecture of LINQ is depicted below and it is self explanatory.

Advantages of using LINQ

There's a common syntax for querying any data source mentioned above. This eliminates the one source - one query language concept. I.e. for example Relational Data -> SQL, XML Documents -> XPath and .Net objects -> .Net built in operators such as foreach.
Able to use LINQ with .Net 1.x and .Net 2.0 objects
Able to extend LINQ to support new classes and technologies
Integrated to the .Net framework thereby accessible from any .Net compliant language (native code) and make use of their stregths and compile time syntax checking. E.g. it inherits the new C# language features like,

Implicitly typed variables e.g. var keyword
Extension methods
Lambda expressions
Anonymous types
Expression Trees

Avoids dynamic creation of string queries within native code (e.g. C#) and thereby avoiding the disadvantage of not having compile time checking of queries. I.e. eliminating mixture of native code and none native code. This also saves time on creating a dynamic query.
Intelli sense is available in Visual Studio
Designer support
Gives more power to the front-end programmer to manipulate data
Shorter learning curve
Could access stored procedures and user defined functions in a relational database

Disadvantages

Mainly focus on or support SQL Server but not Oracle or other databases such as MySQL, DB2. Others have to provide their own provider model or extension.
Lack of "Left/ Right" keywords in a Join even though the objectives are met
Data manipulation logic/code is written in the application rather than the DB end in LINQ to SQL.

This would be a problem when we want to change the logic without changing or re-compiling the application code
Problem of viewing the execution plan and optimising the query

Database programmers would be jobless (Joke!)

Summery

LINQ is a common method of accessing objects that implements IEnumerable <T> interface, relational data, text files and XML. This gives an extension and a cool new addition to the strength of .Net compliance languages even though there are several disadvantages of it.

Rule Of Thumb

I'm pretty sure LINQ will not replace classic SQL, T/SQL or PL/SQL but it will extend the data manipulation capability of the programmer. Its a pretty cool tool to be in our tool box. We as the programmers must decide when to use it and when not to.

References

MSDN - 101 LINQ Samples

The LINQ project

ScottGu's Blog

The evolution of LINQ and its impact on the design of C#

Rediscovering IEnumerable<T> - by Tomas Restrepo

What is LINQ? by Saquib Ullah

Dedicated website for LINQ

Is LINQ the future of database development? - by Arthur Fuller

Beware with Math.Round() in C#

Manjula Perera — Wed, 26 Dec 2007 07:44:00 GMT

Problem

Recently I found an issue with the Math.Round() function in C# while working on an enhancement project written in Visual Studio 2003. I.e. this function is using the Banker's method. The users of this system didn't like the way figures are getting rounded and they wanted the method used in Excel (Because they are used to Excel ). I.e. Symmetric Arithmetic Rounding method. E.g

Say we want to round 1234.50000 into the nearest integer value. Then Math.Round() returns 1234 whereas MS Excel gives 1235.

I also found a similar issue in SQL Server 2000 some time back. It seems that Microsoft uses contradictory methods of rounding in their products (Visual Studio, SQL Server, Visual Basic, Excel etc.)

Most of us learnt this banker's method while schooling. But it seems that there are many other ways of rounding. Click here to view all methods of rounding and how you can implement custom rounding procedures.

Solution

Visual Studio 2003 - If we want to use Symmetric Arithmetic Rounding method we have to write our own function instead of using Math.Round(). See below for a working function found in CoderSource.Net.

public static double roundNum(double num, int place)
{

double n;
n = num * Math.Pow(10, place);
n = Math.Sign(n) * Math.Abs(Math.Floor(n + .5));
return n / Math.Pow(10, place);

}

Visual Studio 2005 - This problem is sorted in this version of Visual Studio. We can now select the rounding method in;

System.Math.Round

Rule Of Thumb

Always ask from the users which method of rounding they want during the system requirements gathering stage. This will avoid us being using the default method of rounding in our chosen development language. In this case C#.

References

Wikipedia

Microsoft Help and Support

CoderSource.Net