/bill's House O Insomnia : LINQ To ADO.NET

Looking for some .NET Developers

William — Sat, 07 Jun 2008 02:19:26 GMT

A client of mine located in the Aiken/Columbia South Carolina Area has asked me if I had any friends who are .NET Developers and looking for a job. They are looking for at least one Junior Developer, on Mid-Level Developer and several Senior developers. I know these folks quite well and I can vouch for the following:

They pay extremely well
Generous benefits package
There's plenty of cool people on their staff
They are growing at an explosive rate so there's plenty of room for upward mobility. There's also a very strong focus on learning/teaching and career development.
They are an Agile/SCRUM shop
Currently developing with the following technologies:

Visual Studio Team System 2008 / .NET 3.5 Framework
Windows Communication Foundation
Windows Presentation Foundation
ASP.NET
LINQ
Silverlight
Windows Mobile 5/ Windows Mobile 6/ .NET Compact Framework
Sql Server 2005 / Sql Server 2008
Windows Installer for XML
Sandcastle

If you're in the area and looking for a job... if you know someone who looking for a job.... or if you're willing to move, please drop me a line using the Contact option on my blog or emailing me directly at WilliamRyan@gmail.com and I'll put you in contact with them. They are looking to hire folks immediately so I can probably get you an interview within a few days.

Junior Developer:

Ideal candidate will be a recent college graduate with a Computer Science of MIS degree. No experience is necessary for this position. The main soft-skill qualifications for this position are:

A true love for development
Strong desire to learn
A desire to stand out among one's peers

The hard-skill qualifications include a good theoretical understanding of at least two of the following:

Object Oriented Design and Analysis
Relational Database theory
Design Patterns
Familiarity with at least two of the following: C, C++, Java, C#, VB.NET

This is essentially a dream job for recent college grads b/c the job is being offered "no experience required". Since they are a SCRUM/Agile shop, you'll get to work extensively with their Senior and Mid level devs via Pair Programming. You'll be able to pick an area to specialize in which you will decide on for yourself. Additionally, you'll be using some of the most sought after Microsoft technologies available. Go to Monster.com or Dice.com and see for yourself how much demand there is for the above technologies and how much those jobs pay. You'll get to work with these on day 1 and essentially carve out a path for yourself using whichever technologies you like the best. If you want to be a "UI" expert, that's where you'll be put. If you want to be a Web Services dev, again, that's what you can focus on. If you want to be an expert buildmaster who specializes in installers, that's what you'll get to do. The company is looking for some excellent candidates and willing to offer a really fun and great paying job with plenty of training and career development available.

Mid-Level Developer:

The ideal candidate will have a computer science or MIS degree and 1-3 years of development experience. The ideal candidate will have two or more the following abilities:

Solid command of OOP/OOD using C++, C#, Java or VB.NET
Test Driven Design
Service Oriented Architecture
Familiarity with MySql, Sql Server (T-SQL), Oracle (PL/SQL)
Basic understanding of both Winforms and ASP.NET
Basic familiarity with Web Services, MSMQ, Enterprise Services/COM+, .NET Remoting, DCOM, J2EE, Java Beans

Just like the Junior development positions, these ones will provide a great deal of flexibility to learn and specialize the area of your choice. These are considered 'fast track' positions to move into the Senior Developer or Architect roles

Senior Developer:

The ideal candidate will be someone with at least 4 years experience. This person will love challenges and love coming up with solutions to problems that other people run from. They will be people that love figuring out how to do things that everyone else said can't be done. They will be the stereotypical Alpha-Geek, Someone that spends their spare time answering quiz questions like these:

All of the requirements for the Mid-Level Developer as well as several of the following skills:

Proficiency with T-Sql or PL/SQL. You should be able to write a 5 table join on your own. You should have written several stored procedures that were > 100 lines long.
Strong command of query tuning and ability to easily spot design flaws
Ability to design 'real' objects.

Someone who pays meticulous attention to the scope modifiers of their classes/functions/properties
Someone who understands the problems associated with coupling and strives to avoid it.
Someone who can write and use events in their classes without thinking twice about it.
Someone with a solid understanding of thread safety and thread synchronization
Someone who is comfortable using several different design patterns
Someone who is comfortable implementing several different interfaces in one object, using combinations of interface implementation and inheritance and someone who can use inheritance responsibly

Keeps up with technology, reads computer books regularly, has favorite blogs in multiple disciplines and/or blogs themselves, attends or speaks at user's groups, is active in one or more online forum or newsgroup
Someone who answers "Which is better, C# or VB.NET?" with "Either can be better depending on the circumstances but I'm comfortable writing in either of them" and then "But I've been learning F# lately and it's really been growing on me"
Experience with .NET Remoting, Web Services & Web Services Enhancements, MSMQ, Enterprise Services and/or WCF
Ability to create syntactically correct UML diagrams (meaning they can do more than write the letters "UML" on their resume) and if not, they are willing to learn to do this.
Understands data structures solidly and could easily implement their own HashTable or LinkedList
Someone who's always looking to come up with a newer, cooler, faster, and more secure way to do implement something
Experienced with either Biztalk server or Sharepoint
Takes pride in their code without falling in love with it or getting all defensive about it. Ability to acknowledge the fact that everyone makes mistakes and can talk about their mistakes/bugs without getting defensive.
Someone who is the first to raise their hand whenever the boss says "I need someone to learn ____________, do I have any volunteers"

Basically, if you love development, love creating new cutting edge solutions all the while making a lot of money and having a lot of fun you definitely should talk to these folks. If you're interested...... Please drop me a line using the Contact option on my blog or emailing me directly at WilliamRyan@gmail.com and I'll put you in contact with them.

Dabbling in LINQ to ADO.NET

William — Sun, 06 Jan 2008 02:13:00 GMT

I'll be doing a training seminar in Stockholm next month and I've been trying to create some compelling examples to illustrate various concepts. Although it's keeping me busy, there's a lot I've been working on that's blogworthy.

One concept in LINQ to SQL that's I am pretty fond of is the use of Entities. There's so much you can do with Entities that it would take quite a few posts to do them justice, but I'll show a simple example of how they can be used. Assuming we're using SQL Server 2005 for this example, I have a database table with the following table definition:

GO /****** Object: Table [dbo].[Bank] Script Date: 01/05/2008 21:14:48 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ONGO SET ANSI_PADDING ON GO CREATE TABLE [dbo].[Bank]( [BankID] [int] IDENTITY(1,1) NOT NULL, [Name] [varchar](150) COLLATE SQL_Latin1_General_CP1_CI_AS NULL, [URL] [varchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL, [bigLogo] [varchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL, [smallogo] [varchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL, CONSTRAINT [PK_Bank] PRIMARY KEY CLUSTERED ( [BankID] ASC ) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF ,ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON)

ON [PRIMARY] ) ON [PRIMARY] GO SET ANSI_PADDING OFF

So the first thing we need to do is create a class with the same definition (note, if you are using a member name that's the same as the column name in the db, no additional steps need taken. If you use different names, then you need to specify a Name value . Field names are not case sensitive [meaning as long as they have the same spelling as the field in the db, the capitalization can be different]). So you use [Column(Name="DBColumnName")] public Type AliasNameYouWantToUse

using System.Linq;
using System.Linq.Expressions; 
using System.Data.Linq.Mapping;
namespace Ryan.Samples.Linq.ADONET {
     [Table(Name="Bank")] 
     public class Bank { 
     [Column]
     public Int32 BankID;
     [Column]
     public String Name; 
     [Column] 
     public String URL;
     [Column] 
     public String biglogo;
     [Column]
     public String smallogo;
    }
}

Now, we have a Bank class which corresponds to the Bank table in the database. For this sample, I created a static class with a static property named Globals and ConnectionString respectively. Now, I compose a quick LINQ query to retrieve all of the data in the table except records where the Bank's Name is PNC:

static void Main(string[] args)
{
   DataContext db = new DataContext(Globals.ConnectionString);
   Table <Banks> = db.GetTable<Bank>();

     var query =
           from b in Banks
           where b.Name != "PNC"
     select new { b.BankID, b.Name, b.URL };

     foreach (var row in query)
     {
         Console.WriteLine(row);
     }
     Console.ReadLine();
}

The syntax is pretty straightforward on the LINQ side so it doesn't really need explaining - if you can't tell what it's doing though, it's selecting each value that doesn' t have 'PNC' as a name. The Select statement is using a new C# language feature known as Anonymous types meaning that, a new type is being created without a traditional definition - that's why the new keyword is used.

When I first learned LINQ though, I wondered how this worked. Was the whole table retrieved from the database and then records restricted via LINQ? If so, this would seem very wasteful b/c by virtue of the restriction, you know you're only using a subset of the total values so why pull down everything? Fortunately that's not what happens. GetTable doesn't acttually pull down everything from the table - it's merely an instruction about how to generate the query it will use. As you probably have noticed, nowhere in here have we defined anything reminiscent of the CommandText property you'd use with a IDBCommand object. To prove that you aren't pulling down a whole table as you might with the old TableDirect instruction, run profiler before this code block executes. The results will show the following (assuming you are logging the same values).

Here's the resulting output:

exec sp_executesql N'SELECT [t0].[BankID], [t0].[Name], [t0].[URL]
FROM [Bank] AS [t0]
WHERE [t0].[Name] <> @p0',N'@p0 nvarchar(3)',@p0=N'PNC'

And just for the record, nothing before this ran a query on this table let alone one without a restriction. The output for running this code is shown below:

{ BankID = 1, Name = Bank of America, URL = www.bankofamerica.com }

{ BankID = 2, Name = Citi Bank, URL = www.citibank.com }

{ BankID = 3, Name = 1st Tennessee, URL = http://www.firsttennessee.com/ }

{ BankID = 4, Name = Citi Group, URL = www.citigroup.com }

{ BankID = 5, Name = JP Morgan, URL = www.jpmorgan.com }

{ BankID = 7, Name = UMB, URL = www.umb.com }

{ BankID = 8, Name = US Bank, URL = www.usbank.co }

{ BankID = 9, Name = BMO Financial Group, URL = www4.bmo.com/ }

{ BankID = 10, Name = M & T, URL = http://www.mandtbank.com/ }

{ BankID = 11, Name = National City, URL = http://www.nationalcity.com }

This brings up one other point... I could have changed the Console.WriteLine to just write out one or more of the properties of 'row'. In general, I make a rule of *always* overriding the ToString() method in any object I create just so that I can use it for meaningful information. With LINQ in particular, this becomes particularly useful b/c had I not used an anonymous type, (so the last line would read 'select b;' instead of 'select new {b.BankID, b.Name, b.URL}; I would have had the following useless output:

Ryan.Samples.Linq.ADONET.Bank

I could get around that by formatting the output in the Console.WriteLine method but that's might inelegant. Instead, by overriding the ToString() method, I can get the following output instead:

<I''ve truncated several records just for the sake of readability>

BankID - 1

Name - Bank of America

URL - www.bankofamerica.com

biglogo - baclogo.jpg

smallogo - bigbanksmall.jpg

BankID - 2

Name - Citi Bank

URL - www.citibank.com

biglogo - citibanklogo.jpg

smallogo - bigbanksmall.jpg

BankID - 3

Name - 1st Tennessee

URL - http://www.firsttennessee.com/

biglogo - 1sttennlogo.jpg

smallogo - 1sttennsmall.jpg

Needless to say, this is a lot more useful than simply knowing the fully qualified object name.