Let’s say you have a simple relationship between two tables.  Let’s call it User and Address.  Let’s just say for simplicity a user has one address.  In CodeFirst, you would model it with tables like the following:

public class User
{
        [Key]
        public long Id { get; set; }
        public virtual Address Address { get; set; }
       // more details about user, name, etc.
}

public class Address
{
       [Key]
        public long Id { get; set; }
        public string City {get;set;}
        // more details about address, state,zip,etc.
}

Now, you will end up with an Address table that has a column named something like User_Id.   YUC!!!  Who puts underscores in column names anymore (well, certainly I don’t.

You may think all you need to do to solve this is put a foreign key column and attribute in the Address table as follows:

public class Address
{
     [Key]
     public long Id {get;set;}

     [ForeignKey]
     public long UserId {get;set;}

     public string City {get;set;}
}

But, when you do that, you will be greeted with an error that looks like the following:

System.Data.Entity.Edm.EdmAssociationEnd: : Multiplicity is not valid in Role ‘EmailAccount_User_Source’ in relationship ‘EmailAccount_User’. Because the Dependent Role properties are not the key properties, the upper bound of the multiplicity of the Dependent Role must be ‘*’.

or

The ForeignKeyAttribute on property ‘UserId’ on type ‘EFCodeFirstLib.CodeFirstModels.EmailAccount’ is not valid. The navigation property ‘User’ was not found on the dependent type ‘EFCodeFirstLib.CodeFirstModels.EmailAccount’. The Name value should be a valid navigation property name.

Pretty clear what to do, huh?

Well, I suppose if you know EF EDMX and a whole bunch of other acronyms, you probably will figure it out, but if you don’t I’ll tell you.  You basically need to include the User property in your Address class.  It should then look like:

public class Address
{
  [Key]
  public long Id {get;set}

  public User User {get;set;}  // important!
  [ForeignKey]
  public long UserId {get;set;}

  public string City {get;set;}
}

And now, you will have a “properly” named foreign key column “UserId” with no underscores!

My 2Cents.

Introduction

I’ve now been using Microsoft’s Entity Framework CodeFirst for a month or two and am very impressed with how easily it is to access data in a type safe way.  I also have noticed that I need to be extra careful about how I form my LINQ or I can accidentally cause the Sql Server to do tons of extra work (tons meaning lots, not actually tons).

I’ll basically explain this with actual code snippets to demonstrate my point and help you understand what I’m talking about. Let’s say you have a set of classes representing your model that basically have a master record and an associated detail record that contains an reference to a table that hold images.  That is, basically, something like this:

 public class User
    {
        [Key]
        public long Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public virtual ICollection<AddressBookEntry>
                        AddressBookEntries { get; set; }
     }

 public class    AddressBookEntry
    {
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public long Id { get; set; }
        public ImageDetail ImageDetail { get; set; }
    }

public class ImageDetail
    {
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public long Id { get; set; }

        [Required(ErrorMessage = "Image Without Data Means Nothing")]
        [Column(TypeName = "image")]
        public byte[] ImageDataBytes { get; set; }
    }

The Goal For Your Query

The goal for your EF query is you want to create a simple image viewer web page.  That is, you want to get the following information from your query that will list the address book of a given person.  The columns you want back for each address book entry (of a given user) are as follows:

• AddressBookEntry.Id
• ImageDetail.Id

You don’t actually want the blob data itself because you will let the html img tag actually get the data for you.

The Wrong Way

You are probably tempted to write a query that looks something like this:

var userAccount =
       db.Users.Where(a => a.Id == userIdIWant).
               Include(p => p.addressBookEntries.Select(o => o.ImageDetail).
                            FirstOrDefault();

The problem with this is if you have 4MB image in your ImageDetail table, it will all come down when you materialize your query.

The Right Way

The correct way is to create a resulting anonymous object something like this:

var userAccount =
      db.Users.Where(a => a.Id == userIdIWantd).
              Include(p => AddressBookEntries.Select(o => o.ImageDetails).Select(p=>new {
                 p.Id,
                 p.ImageDetails.Id
              }));

Conclusions

Sorry if the syntax here is not perfect.  I did not actually use these tables, my problem is a little different, but I just wanted to get my point across about how important making anonymous (or staticly typed) result sets are for performance and how easily you can make code that will kill the performance of your server.

Problem

So, if you have been doing development with Visual Studio 2010, Entity Framework CodeFirst, SqlServer or SqlServerCE for any amount of time, you’ll quickly run into the problem that the database can not be reinitialized because it is open.  Basically, the scenario is this.

1)  Put in your Global.asax.cs file a line that always recreates the database (naturally because you are in a development mode and as you constantly change your model and seed data).  The line is something like this:  Database.SetInitializer(new DropCreateDatabaseAlways<SiteDB>());

2)  Run your application with something like Debug/Run (All is fine)

3)  Go into the database browser (either in Visual Studio or Enterprise Manager)  and look at some data.

4)  Run your application again and you will get this error: “[SqlException (0x80131904): Cannot drop database "NewYorkTimesDb" because it is currently in use.]”.  This is because your database browser has a connection to the database and until it is dropped, you can not drop the catalog.

Solutions

The easiest and guaranteed to work solution is just to restart your SqlServer database server (control panel, services).  This is what I use to do but finally got tired of that because it takes about 20 seconds and, well, I’m very impatient.

The other solution I found in the forums (can’t find the link right now) is to execute the following script from the master database catalog:

use master
ALTER DATABASE NewYorkTimesDb
   SET SINGLE_USER WITH ROLLBACK IMMEDIATE
ALTER DATABASE NewYorkTimesDb SET MULTI_USER

Basically, just switching from multi-user to single-user and back clears the connections.

HTH’s!

So, this is not a big tip, but worth at least 10 minutes to figure it out on your own.  Here is to saving you 10 minutes:

SELECT LEFT (userlastname, 1) as alpha,       count(id)FROM attendeesWHERE id IN (              SELECT attendeesid              FROM AttendeesCodeCampYear              WHERE codecampyearid = 6      )GROUP BY  LEFT (userlastname, 1)OORDER BY LEFT (userlastname, 1)

It’s pretty self explanatory.  Our case is we have two tables that we track code camp attendees.  One is the master list, and the other is a detail by year.  (6 is this year)

And, the results:

> NULL    1

>        6

> .       1

> @       1

> _       18

> A       319

> B       488

> C       543

> Ç       2

> D       313

> E       84

> F       169

> g       368

> H       340

> I       49

> J       190

> K       474

> L       460

> M       592

> N       255

> O       79

> P       427

> Q       14

> R       336

> S       776

> T       302

> u       27

> V       191

> w       296

> X       21

> y       176

> Z       100

I’ve got a small project (1 table) that I’d like to include in an asp.net website project so I decided to give it a try.  For the most part, things have gone smoothly, however I did have a couple hiccups I’d like to mention.  One cost me $9 because I was doing this implementation on an airplane and immediately, I had a failed connection with a confusing error that I needed Bing to lookup  (more details below).

Method Names Changed

I have to wonder why Microsoft decided to change the names of the methods in ADO.NET.  Seems to me that all the names should be the same whether I’m using Sql Server, Sql Server Express or Sql Server CE.  My expectation was that the statement:

using (var connection = new SqlConnection(testDataContext.ConnectionString)) {..

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 – Error Locating Server/Instance Specified)

using (var connection = new SqlCeConnection(connectionString)) {...

And things now work (my connection string is actually what I’ve pasted below).

<connectionStrings>  <add name="ConnectionStringMxMessage" connectionString="Data Source=|DataDirectory|\MxMessageDb.sdf"       providerName="System.Data.SqlServerCe.4.0" /></connectionStrings>

Bottomline, all ado.net commands need the Ce in them.

Getting Identity Column After Insert Fails

My expectation is that what has worked for a very long time in Sql Server for me should work in Sql Server CE.  The most simple pattern of inserting a row and getting back the value of the identity column does not work the same.  My original code looks like this (which fails):

using (var connection = new SqlCeConnection(testDataContext.ConnectionString))    {        connection.Open();        using (var sqlCeCommand =            new SqlCeCommand(                "INSERT INTO message (Name, Subject, Header, Body, Footer) Values                     (@Name);SELECT @@IDENTITY",                connection))        {            sqlCeCommand.Parameters.Add("@Name", SqlDbType.NVarChar).Value = Name;            // problem, need to do separate select to get this to work            sqlCeCommand.Parameters.Add                (new SqlCeParameter("@IDENTITY", SqlDbType.Int)                                            {                                                Direction =                                                    ParameterDirection.Output                                            });

            using (var reader = sqlCeCommand.ExecuteReader())            {                while (reader.Read())                {                    message.Id = reader.IsDBNull(0) ? 0 :                       Convert.ToInt32(reader.GetDecimal(0));                }            }        }    }}

To fix it, it seems that you can not send two sql commands on the same execution (separated by semicolon).  That is, after the first command (without the SELECT @@IDENTITY) you need to do another SqlCeCommand as follows:

using (var sqlCeCommand2 =    new SqlCeCommand(        "SELECT @@IDENTITY",        connection)){    message.Id = Convert.ToInt32(sqlCeCommand2.ExecuteScalar());}

 

Conclusions

Well, things are working, but I have not done much and I’ve had a couple of stumbles.  Hopefully I’m done with stumbling for now.

<add name="MyConnName" connectionString="Server=.;Database=mydbcatalogname;Trusted_Connection=True;"     providerName="System.Data.SqlClient" />

Notice that I’m using the “.” as the server name.  This allows me to reference the local system where my sqlserver lives. Not necessarily a best practice, but often is the case.

Upside

One big benefit is if you fall victim to a disk scraping attack, or someone gets a hold of your source (maybe from version control?), you don’t give up your passwords.

Downside

If you SqlSever is not on the system system as your web project or application, then this become more tricky because of the cross system authentication issues.  If you have active directory installed on both systems, then this works also.

If you’ve started using SqlAzure for your SqlServer with your Azure application, you’ve probably discovered that you get a reasonable number of connection failures.  The advice from the Azure team is add retry logic to all your connections to SqlAzure. There is a long discussion posted by the Azure team here.

The key paragraph states the problem as follows:

The Problem
One of the things that SQL Azure does to deliver high availability is it sometimes closes connections. SQL Azure does some pretty cool stuff under the covers to minimize the impact, but this is a key difference in SQL Azure development vs. SQL Server development.

Basically, what this means is that you must be able to deal with connections failing when you call SqlAzure.  Something that all of probably should have been doing forever, but because most of the time SqlServer is running on your local LAN and the likelihood if a connection failing was next to zero unless something else was going terribly wrong.  Certainly not something we had to do on regular basis.  To emphasize that even more, most of the controls built into asp.net that open connections to sqlserver don’t even do this and that’s from Microsoft itself.

The solution proposed in the thread mentioned above basically has you add tons of code to everyplace you access a connection object.  Personally, I don’t like that because I have hundreds if not thousands of places I open connections and inserting tens of thousands of lines of extra new untested code is a little scary.

So, what to do?

Fortunately, another team at Microsoft, known as the Windows Server AppFabric Customer Advisory Team published a general purpose solution using Extension Methods and some darn clever coding wrote a great article and published code including azure examples that solves this problem very elegantly without requiring a lot of changes to your existing code base.

In this article I plan on giving an example and publishing a sample project that uses this code with SqlAzure to solve the connection retry problem.  My goal here is not to simply restate what they published but to simply have a very simple concrete example of using their library.

Design Goal

We have two goals.

1. Change as little code as possible
2. Log Connection Errors when they happen With Locations
3. Make sure not to trap errors that are NOT connection related such as bad column names

Incorrect Code

So, this is what the original code looks like that will fail because it does not have connection retry logic:

public static int UsersIdFromUserNameNoConnectionRetry(string userName){    var retUsersId = 0;    const string sql =        @"SELECT Id FROM Users            WHERE Username = @Username";

    using (var sqlConnection = new SqlConnection(            ConfigurationManager.ConnectionStrings["CRStorageWebConnectionString"].            ConnectionString))    {        sqlConnection.Open();        using (var sqlCommand = new SqlCommand(sql, sqlConnection))        {            sqlCommand.Parameters.Add("@Username", SqlDbType.NVarChar).Value = userName;            using (var reader = sqlCommand.ExecuteReader())            {                while (reader.Read())                {                    retUsersId = reader.IsDBNull(0) ? 0 : reader.GetInt32(0);                }            }        }    }    return retUsersId;}

So, if there is a connection, an exception will get thrown and will need to be caught, but then the method will not have done it’s job.

Correct Code With Retries

So, now take a look at the revised code after the library is setup and used.  The setup is non-trivial, but you just have to do that once and then you can simply fix all your other code with very few changes.  Below is the new code with connection retry logic built in.

public static int UsersIdFromUserName(string userName){    var retUsersId = 0;    const string sql =        @"SELECT Id FROM Users            WHERE Username = @Username";

    using (var sqlConnection =        new ReliableSqlConnection(            ConfigurationManager.ConnectionStrings["CRStorageWebConnectionString"].            ConnectionString,            new RetryUtils("", "UsersIdFromUserName").GetRetryPolicy()))    {        sqlConnection.Open();        using (var sqlCommand = new SqlCommand(sql, sqlConnection.Current))        {            sqlCommand.Parameters.Add("@Username", SqlDbType.NVarChar).Value = userName;            using (var reader = sqlCommand.ExecuteReader())            {                while (reader.Read())                {                    retUsersId = reader.IsDBNull(0) ? 0 : reader.GetInt32(0);                }            }        }    }    return retUsersId;}

1. The first is instead of create an SqlConnection(…) we are creating a ReliableSqlConnection(…).  The ReliableSqlConnection takes an extra parameter which basically wraps the retry logic used, as well as labelling this connection so when it fails, it gets logged.  In the log, there will be the comment “UsersIdFromUserName” so we know what method threw the retry.
2. The second is slight change we when we create the SqlCommand, we have to add the property .Current to it so we know we are talking about the currently executing connection.  There may be a default way to handle this but I could not figure it out.

The Setup Pieces

The project has all kinds of stuff in it that build quite nicely, run and test under vs2010.  All I’m interested in is the ado.net piece and the retry logic around that.  I actually used the 1.2 version, however I now see there is a 1.3 version with some improvements.  I would post my project but I don’t want to post it with old code so I’ll just tell you the steps I went through so you can do the same.

Build the class library

Compile the project and make sure you have the dll from the library lincluded in your actual visual studio project.  The library you want is Microsoft.AppFabricCAT.Samples.Azure.TransientFaultHandling.

Update Your Web.config

Add the config section below to your web.config file.

<configSections>    <section name="RetryPolicyConfiguration"          type="Microsoft.AppFabricCAT.Samples.Azure.TransientFaultHandling.Configuration.RetryPolicyConfigurationSettings,            Microsoft.AppFabricCAT.Samples.Azure.TransientFaultHandling" /></configSections>

<RetryPolicyConfiguration defaultPolicy="FixedIntervalDefault" defaultSqlConnectionPolicy="FixedIntervalDefault"          defaultSqlCommandPolicy="FixedIntervalDefault" defaultStoragePolicy="IncrementalIntervalDefault"          defaultCommunicationPolicy="IncrementalIntervalDefault">    <add name="FixedIntervalDefault" maxRetryCount="10" retryInterval="100" />    <add name="IncrementalIntervalDefault" maxRetryCount="10" retryInterval="100" retryIncrement="50" />    <add name="ExponentialIntervalDefault" maxRetryCount="10" minBackoff="100" maxBackoff="1000" deltaBackoff="100" /></RetryPolicyConfiguration>

This defines a new section in your web.config, then implements it with several different retry policies include a default one which seems quite reasonable to me.

If you remember, in the implementation section above, we used a public class called RetryUtils.  This class is actually one I invented as a convenience class to minimize the code I have to update on each use of the ReliableConnection Object.  Just to refresh your memory, the implementation is this:

using (var sqlConnection =                new ReliableSqlConnection(                    ConfigurationManager.ConnectionStrings["CRStorageWebConnectionString"].                    ConnectionString,                    new RetryUtils("", "UsersIdFromUserName").GetRetryPolicy()))

The actual code fo rthe class RetryUtils is below here.  You’ll have to stick this someplace in your project.

namespace Utils{

    public class RetryUtils    {        public string Username { get; set; }        public string CallersName { get; set; }

        public RetryUtils(string username, string callersName)        {            Username = username;            CallersName = callersName;        }

        public RetryUtils()        {            Username = string.Empty;            CallersName = string.Empty;        }

        public RetryPolicy<SqlAzureTransientErrorDetectionStrategy> GetRetryPolicy()        {            var retryPolicy = new RetryPolicy<SqlAzureTransientErrorDetectionStrategy>                 (RetryPolicy.DefaultClientRetryCount, RetryPolicy.DefaultMinBackoff,                  RetryPolicy.DefaultMaxBackoff,                  RetryPolicy.DefaultClientBackoff);

            retryPolicy.RetryOccurred += RetryPolicyRetryOccurred;

            return retryPolicy;        }

        void RetryPolicyRetryOccurred(int currentRetryCount, Exception lastException, TimeSpan delay)        {            GeneralUtils.GetLog4NetAllDataContext().AddLog4NetAll(new Log4NetAll                                                    {                                                        Date = DateTime.UtcNow,                                                        EllapsedTime = 0,                                                        ExceptionStackTrace = lastException.StackTrace,                                                        Message = "RetryCount: " + currentRetryCount + " delay: " + delay.Seconds,                                                        ExceptionMessage = lastException.Message,                                                        Logger = "",                                                        Level = "Error",                                                        UserName = Username,                                                        PartitionKey = Username,                                                        RowKey = Guid.NewGuid().ToString()                                                    });        }           }}

Non Connection Related Errors

Conclusions

Say you want to delete all but the last 30 days of activity.  If you just simply say DELETE FROM table WHERE id>10000, you will cause this to happen in one transaction and likely, you will get an error.  That’s the best case.  The worst case is your system tries to do this, eventually consumes all the resources in your computer and crashes your server.

CREATE PROCEDURE dbo.DeleteRowsInGroupsBeforeNdaysLog4NetAll@NoOfRowsToDelete int,@DaysBeforeTodayToDelete intASBEGIN

  DECLARE @DateToDeleteBefore date    -- Number Of Days To Delete Records From  DECLARE @DateToday datetime         -- To Hold Todays Date  DECLARE @PrintMessage varchar(256)  -- To Hold Print Message          DECLARE @CurrentRowCount int        -- Scratch Var For Counting Rows

  SET @DateToday = GetDate()

  SELECT @CurrentRowCount =         (           SELECT COUNT(*)           FROM dbo.Log4NetAll           WHERE Date <(@DateToday - @DaysBeforeTodayToDelete)         ) 

  WHILE (@CurrentRowCount > 0) BEGIN      DELETE TOP (@NoOfRowsToDelete)      FROM dbo.Log4NetAll        WHERE Id IN (        SELECT TOP (@NoOfRowsToDelete) Id         FROM Log4NetAll        WHERE Date < (@DateToday - @DaysBeforeTodayToDelete)        ORDER BY Id ASC)

       -- Count the records again       SELECT @CurrentRowCount =         (           SELECT COUNT(*)           FROM dbo.Log4NetAll           WHERE Date <(@DateToday - @DaysBeforeTodayToDelete)         )        SET @PrintMessage = N'Deleting This Many Rows: '                            + (CAST(@CurrentRowCount AS nvarchar(10)));       PRINT @PrintMessage;  END  END

Then, do Execute the Procedure, you would call it as follows assuming you wanted to delete the code in batches.

DECLARE @NoOfRowsToDelete int;DECLARE @DaysBeforeTodayToDelete int;

SET @NoOfRowsToDelete = 100;SET @DaysBeforeTodayToDelete = 30;

EXEC [dbo].[DeleteRowsInGroupsBeforeNdaysLog4NetAll]   @NoOfRowsToDelete, @DaysBeforeTodayToDelete ;

The output of calling this might be:

Query execution was canceled by user request.

Deleting This Many Rows: 19199

Deleting This Many Rows: 19099

Deleting This Many Rows: 18999

Deleting This Many Rows: 18899

Deleting This Many Rows: 18799

Deleting This Many Rows: 18699

Deleting This Many Rows: 18599… (All the way until 0)

Hope this helps!

The company I’m now working at is small and we don’t have a lot of resources to maintain hardware and do operating system type support.  We do have a high load requirement so we need a very robust supported solution.  Before this, I’d always been in the under $50 per month type plan with ORCSWeb, but I decided I needed more servers and a higher level of support.  I really did not know what level of support to expect when signing up for the managed servers but decided to go for it anyway.

All  can say is WOW!!!  I am over the top impressed.

We currently have 3 virtual servers hosted at ORCSWeb.  One, we use as a development server, and the other two are in a webfarm configuration.  I’ve always believed that when you go into production with a web site it’s critical you start with 2 servers in a webfarm.  it’s really easy to go from 2 to 10, but can be very painful to go from 1 to 2.   That’s a topic for another post, but suffice it to say, 2 is the minimum.

So, why am I so impressed?  First, the support team they assigned to me is totally awesome.  They all are focussed and competent which is a total relief compared with most hosting companies I’ve dealt with.  Other companies always have good people, but it seems to be the bad ones that really give me cause to remember.  Second, because I paid extra for the full managed support options on our three servers, I’ve been able to ask the things like the following.  Almost all of them I could do myself, but I’m swamped with my technology role in the new company and really appreciate being able to hand stuff like this off.

• I’ve pointed my MX record at my .149 server.  Could you please set up email and create the following 7 accounts.
• Please Setup a secure ftp server at the following address with the following username and password (and make sure the user is locked down to the root)
• Setup DFS Replication between these two directories on .148 and .149
• Create a RoboCopy script that copies files from my dev server to the .149 mirrored directory
• Please set up web statistics for me on http://www.siliconvalley-codecamp.com
• Please figure out why SqlServer 2008 is not letting me access catalog MyStuff1 from user 3p1 and fix
• Please make a replicate of website MyWeb1.com including the sqlserver catalog’s and put it on MyWeb2.com on server .149
• Please replace the sqlserver catalog MyStuff3 on server .149 with the bak file I uploaded to my ftp server
• I could go on and on, but I think you are getting the idea.
• Always with a smile, 24×7, what else can I say.

By the way, if you want to see one of my sites hosted there, go to http://www.siliconvalley-codecamp.com

Thank you ORCSWeb for making things a lot easier for me.

We’ve been looking to find the best Cloud based host to put our soon to be virally growing web site up on.  Our requirements are it must run IIS7 and use Sql Server 2008 as it’s database. We have lots of wants (like Service Broker, Replication, etc.) but primarily we want the web tier to scale easily.  After doing research and testing, we got frustrated with our options at Amazon’s EC2.  We emailed their support (with our paid support contract) and were basically told we should go do our own Windows research to find out what works best.

At any rate, I emailed Steve Evan’s who is a frequent speaker at conferences and also an expert consultant on all things Windows and IT related and asked for some advice.  He told me that he had been asked that question often recently by others so he would do some research and get back to me.  He did one step better.  He wrote a blog post describing the ups and downs of the different cloud providers including Amazon’s EC2.  I respect Steve’s opinion a lot and rather than try and paraphrase it, I’ll just link to his post.

Here it is:  http://serktools.com/2009/04/20/load-balancing-iis-web-farm-on-amazon-ec2/

Good luck and feel free to post comments here if you’ve got opinions on Cloud Hosting of IIS and Sql Server 2008.

So far, I’ve read the first four chapters and have skimmed the rest.  I am so far very impressed with both how well it’s written and the depth of topics the book covers.  As I read more, I’ll come back and update this post.  I have no doubts I will get a lot out of this book, as I’m sure practically anyone else who buys it will also.

If you want to read more of Lynn’s stuff, check out her blog at http://blogs.msdn.com/socaldevgal/

Microsoft Visual Studio 2010 Premium with MSDN Download – Download Direct from Microsoft

I’ll first try and explain in a nutshell what it is.  Then I’ll go through an example of creating a Visual Studio Database Project out of a site I’ve been working on to show the steps.  Finally, I’ll give a short summary reliving the experience and giving you some other pointers that may help you get through the experience.

What is VS2008 Database Edition?

Basically, what VS2008 does is to first process your existing schema into hundreds (maybe thousands) of little files.  That is, each file is one database thing. That thing might be a table definition, a stored procedure, a trigger, a constraint, a foreign key, etc.  The beauty of this is that now, each thing can be tracked separately.  Say for example, you want to update just one table and someone else on your team wants to update another table in the same schema.  Since the files are now separate files, it’s no problem.  When you grab the latest changes from source control, you will get your friends changes and he will get yours.  Very very clean!

Also, it has a very powerful comparison engine.  Say you update your data outside of this project.  VS2008 Database Edition will compare your definitions in all these little files with either a sql script you generate, or it will connect to an external database and compare to that.  Me personally, I like to use a tool called SqlManager to manage my data.  I can continue to do that, then when I’ve made my changes, I can simply connect VS2008 Database Edition to my updated development database and it will automatically figure out the changes.

So, you may ask, what version do I need to run this of Visual Studio?  The answer is in this link:  http://msdn.microsoft.com/en-us/vs2008/products/cc149003.aspx

Here We Go, Let’s do an Example

So, first, I will open my existing solution which has a web project in it, a data access project as well as other projects.  Then, I create the new Database solution by saying File/Open/New Project/Database Project.

Then, we follow the wizard…

Taking defaults…

Now, I choose my schema.

Press Start…

Once you’ve done that, you’ll now have your schema spread out across your project in little files.  Below is what the "file based" view of your schema looks like.

Notice that the file we are looking at also includes comments for both the table and the columns using the standard extended property documentation format as follows:

GO
EXECUTE sp_addextendedproperty @name = N'MS_Description',
@value = N'tracks all changes from each camp

title;link;guid;pubDate;category;description', @level0type = N'SCHEMA',
@level0name = N'dbo', @level1type = N'TABLE',
@level1name = N'CampFeed';

GO
EXECUTE sp_addextendedproperty @name = N'MS_Description',
@value = N'if true, this is the main news feed from the site.
there should only be one main news feed from any site.  this would
not be feeds like twitter', @level0type = N'SCHEMA',
@level0name = N'dbo',
@level1type = N'TABLE', @level1name = N'CampFeed',
@level2type = N'COLUMN', @level2name = N'PrimaryFeed';

Now, when you actually build the project as follows:

it will generate the full script combining all the files back into one again. Here is where it puts it:

So, that’s about it for now. I haven’t gone into any of the ways to compare and update your schema based on external changes, but we can leave that for another post.

To see a great video by Richard Hundhausen, President of Accentient, a Team Systems Consulting company, go to this link:  http://msdn.microsoft.com/en-us/vsts2008/cc659682.aspx

Also, if you are using Sql Server 2008, make sure you install visual studio 2008 sp1, then go to this link and install the download:  http://www.microsoft.com/downloads/details.aspx?FamilyID=bb3ad767-5f69-4db9-b1c9-8f55759846ed&displaylang=en

Conclusions

From what I can tell, this Visual Studio Database Edition will be a huge help in building database schema’s and database programs (sp’s, triggers,etc.) in a collaborative environment.   If you have the license to use this, I strongly recommend it.  It is definitely going to be part of my tool kit for now on.  Even if I’m the only author in the project.

I’m not a wizard at writing LINQ expressions so I often find myself in Google looking for something similar to what I want, then I put it into my application and run it. This has worked pretty well, but it takes a couple iterations to get it right. It occured to me that someone probably has written a LINQ interpreter so I just guessed the name, LINQPad, typed it into search, and I find the authors of the book C# 3.0 in a nutshell, Joseph Albahari and Ben Albahari, (which I like a lot) have written it.

I download it (it’s an exe file), run it (OK, I trust you guys somehow), and presto, I get a very nice interface that not only has tons of examples built into it with a nice tree view, but lets me make a connection to my database and run LINQ queries against it. It even cancels them when you create one that will run forever (very nice guys!).

So, the query I was going after is I have a huge list of cities that includes states. From that, I just want a unique list of states (this list does not have all the states so I want just the ones contained in it). Below is a screen shot of the LINQPad with my Query in it. I simply pressed the green triangle (trained by Sql Server Enterprise Manager), and presto, my list! Could not be much easier. This tool will be in my box for a long time.

Amazon.com: C# 3.0 in a Nutshell

Grab this now!  It’s a winner, believe me.