From 0568dc10ef0bfaab2b240e3b7696427a6fabc507 Mon Sep 17 00:00:00 2001
From: jletroui <julien.letrouit@gmail.com>
Date: Sun, 6 Nov 2011 09:20:00 -0500
Subject: [PATCH] Simplified a couple of things. Made the event store a single
 table.

---
 .../ContainerCommandBus.cs                    |  6 ++-
 .../SqlServerEventStore.cs                    | 37 ++++++-------------
 .../SqlServerPersistenceManager.cs            |  1 +
 .../Presentation/Views/Shared/Site.Master     |  2 +-
 DDDPart6/Presentation/Web.config              |  2 +-
 DDDPart6/Presentation/schema.sql              | 12 +++---
 6 files changed, 27 insertions(+), 33 deletions(-)

diff --git a/DDDPart6/Infrastructure.Impl/ContainerCommandBus.cs b/DDDPart6/Infrastructure.Impl/ContainerCommandBus.cs
index 24a844e..95c0587 100644
--- a/DDDPart6/Infrastructure.Impl/ContainerCommandBus.cs
+++ b/DDDPart6/Infrastructure.Impl/ContainerCommandBus.cs
@@ -11,10 +11,12 @@ namespace Infrastructure.Impl
     public class ContainerCommandBus : ICommandBus
     {
         private IContainer container;
+        private IPersistenceManager persistenceManager;
 
-        public ContainerCommandBus(IContainer container)
+        public ContainerCommandBus(IContainer container, IPersistenceManager persistenceManager)
         {
             this.container = container;
+            this.persistenceManager = persistenceManager;
         }
 
         public void Send<T>(T cmd) where T : ICommand
@@ -27,6 +29,8 @@ public ContainerCommandBus(IContainer container)
                 try
                 {
                     handler.Handle(cmd);
+                    // Trigger persistence and concurrency checking.
+                    persistenceManager.Commit();
                     handled = true;
                 }
                 catch (ConcurrencyException)
diff --git a/DDDPart6/Infrastructure.Impl/SqlServerEventStore.cs b/DDDPart6/Infrastructure.Impl/SqlServerEventStore.cs
index b64b36d..296ca66 100644
--- a/DDDPart6/Infrastructure.Impl/SqlServerEventStore.cs
+++ b/DDDPart6/Infrastructure.Impl/SqlServerEventStore.cs
@@ -20,40 +20,27 @@ public SqlServerEventStore(IPersistenceManager persistenceManager)
             this.persistenceManager = persistenceManager;
         }
 
+        private const int UniqueKeyViolation = 2627;
+
         public void PersistUncommitedEvents(IAggregateRoot aggregate)
         {
-            persistenceManager.ExecuteNonQuery(
-                "INSERT INTO [Events] (Id, aggregate_id, version, data) VALUES (@Id, @AggregateId, @Version, @Data)",
-                new
-                {
-                    Id = Guid.NewGuid(),
-                    Version = aggregate.Version + 1,
-                    AggregateId = aggregate.Id,
-                    Data = Serialize(aggregate.UncommitedEvents)
-                });
-
-            if (aggregate.Version == 0)
+            try
             {
                 persistenceManager.ExecuteNonQuery(
-                    "INSERT INTO [Aggregates] (aggregate_id, version) VALUES (@AggregateId, 1)",
+                    "INSERT INTO [Events] (Id, aggregate_id, version, data) VALUES (@Id, @AggregateId, @Version, @Data)",
                     new
                     {
-                        AggregateId = aggregate.Id
+                        Id = Guid.NewGuid(),
+                        Version = aggregate.Version + 1,
+                        AggregateId = aggregate.Id,
+                        Data = Serialize(aggregate.UncommitedEvents)
                     });
             }
-            else
+            catch (SqlException se)
             {
-                var rowCount = persistenceManager.ExecuteNonQuery(
-                    "UPDATE [Aggregates] SET Version = @Version WHERE aggregate_id = @AggregateId AND Version = @Expected",
-                    new
-                    {
-                        AggregateId = aggregate.Id,
-                        Version = aggregate.Version + 1,
-                        Expected = aggregate.Version
-                    });
-
-                // The version evolved since we performed the command, so we have to retry the command.
-                if (rowCount != 1) throw new ConcurrencyException();
+                // Thanks Jonathan Oliver's CQRS Event Store
+                if (se.Number == UniqueKeyViolation) throw new ConcurrencyException();
+                throw;
             }
         }
 
diff --git a/DDDPart6/Infrastructure.Impl/SqlServerPersistenceManager.cs b/DDDPart6/Infrastructure.Impl/SqlServerPersistenceManager.cs
index d4b20f8..9743d84 100644
--- a/DDDPart6/Infrastructure.Impl/SqlServerPersistenceManager.cs
+++ b/DDDPart6/Infrastructure.Impl/SqlServerPersistenceManager.cs
@@ -96,6 +96,7 @@ public void Commit()
                     catch (ConcurrencyException)
                     {
                         tx.Rollback();
+                        context[TRANSACTION_KEY] = null;
                         throw;
                     }
 
diff --git a/DDDPart6/Presentation/Views/Shared/Site.Master b/DDDPart6/Presentation/Views/Shared/Site.Master
index f619fb1..5326fd0 100644
--- a/DDDPart6/Presentation/Views/Shared/Site.Master
+++ b/DDDPart6/Presentation/Views/Shared/Site.Master
@@ -16,7 +16,7 @@
 
         <div id="header">
             <div id="title">
-                <h1>Migrating to Event Sourcing - Part 1</h1>
+                <h1>Migrating to Event Sourcing - Part  6-7-8</h1>
             </div>
               
             <div id="menucontainer">
diff --git a/DDDPart6/Presentation/Web.config b/DDDPart6/Presentation/Web.config
index fc455cd..b9d721a 100644
--- a/DDDPart6/Presentation/Web.config
+++ b/DDDPart6/Presentation/Web.config
@@ -4,7 +4,7 @@
         <add name="maindb" connectionString="Data Source=localhost\SQLEXPRESS;Database=DDDPart6;Integrated Security=SSPI;"/>
     </connectionStrings>
     <appSettings>
-        <add key="ReCreateSchemaAtStartup" value="false"/>
+        <add key="ReCreateSchemaAtStartup" value="true"/>
     </appSettings>
     <system.web>
         <compilation debug="true" targetFramework="4.0">
diff --git a/DDDPart6/Presentation/schema.sql b/DDDPart6/Presentation/schema.sql
index 497c2b6..7aa7faa 100644
--- a/DDDPart6/Presentation/schema.sql
+++ b/DDDPart6/Presentation/schema.sql
@@ -1,21 +1,23 @@
-IF EXISTS (SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'[dbo].[failedClasses_to_Student]') AND OBJECTPROPERTY(id, N'ISFOREIGNKEY') = 1) ALTER TABLE [dbo].[failedClasses] DROP CONSTRAINT failedClasses_to_Student
+IF EXISTS (SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'[dbo].[Events]') AND OBJECTPROPERTY(id, N'IsUserTable') = 1) drop table [dbo].[Events]
+
+IF EXISTS (SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'[dbo].[failedClasses_to_Student]') AND OBJECTPROPERTY(id, N'ISFOREIGNKEY') = 1) ALTER TABLE [dbo].[failedClasses] DROP CONSTRAINT failedClasses_to_Student
 IF EXISTS (SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'[dbo].[passedClasses_to_Student]') AND OBJECTPROPERTY(id, N'ISFOREIGNKEY') = 1) ALTER TABLE [dbo].[passedClasses] DROP CONSTRAINT passedClasses_to_Student
 IF EXISTS (SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'[dbo].[Registration_to_Student]') AND OBJECTPROPERTY(id, N'ISFOREIGNKEY') = 1) ALTER TABLE [dbo].[Registration] DROP CONSTRAINT Registration_to_Student
-IF EXISTS (SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'[dbo].[Events]') AND OBJECTPROPERTY(id, N'IsUserTable') = 1) drop table [dbo].[Events]
-IF EXISTS (SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'[dbo].[Aggregates]') AND OBJECTPROPERTY(id, N'IsUserTable') = 1) drop table [dbo].[Aggregates]
+
 IF EXISTS (SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'[dbo].[Class]') AND OBJECTPROPERTY(id, N'IsUserTable') = 1) drop table [dbo].[Class]
 IF EXISTS (SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'[dbo].[failedClasses]') AND OBJECTPROPERTY(id, N'IsUserTable') = 1) drop table [dbo].[failedClasses]
 IF EXISTS (SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'[dbo].[passedClasses]') AND OBJECTPROPERTY(id, N'IsUserTable') = 1) drop table [dbo].[passedClasses]
 IF EXISTS (SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'[dbo].[Student]') AND OBJECTPROPERTY(id, N'IsUserTable') = 1) drop table [dbo].[Student]
 IF EXISTS (SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'[dbo].[Registration]') AND OBJECTPROPERTY(id, N'IsUserTable') = 1) drop table [dbo].[Registration]
 
-CREATE TABLE [dbo].[Events] ( [Id] uniqueidentifier NOT NULL, aggregate_id uniqueidentifier NOT NULL, [version] int NOT NULL, [data] varbinary(4000) NOT NULL, PRIMARY KEY CLUSTERED ([Id]) ON [PRIMARY]) ON [PRIMARY]
-CREATE TABLE [dbo].[Aggregates] ( [aggregate_id] uniqueidentifier NOT NULL, [version] int NOT NULL, PRIMARY KEY CLUSTERED ([aggregate_id]) ON [PRIMARY]) ON [PRIMARY]
+CREATE TABLE [dbo].[Events] ( [Id] uniqueidentifier NOT NULL, aggregate_id uniqueidentifier NOT NULL, [version] int NOT NULL, [data] varbinary(4000) NOT NULL, PRIMARY KEY ([Id]) ON [PRIMARY], UNIQUE ([aggregate_id], [version]) ON [PRIMARY]) ON [PRIMARY]
+
 CREATE TABLE [dbo].[Class]([Id] [uniqueidentifier] NOT NULL,[version] [datetime] NOT NULL,[name] [nvarchar](255) NULL,[credits] [int] NULL, PRIMARY KEY CLUSTERED ([Id]) ON [PRIMARY]) ON [PRIMARY]
 CREATE TABLE [dbo].[failedClasses]([StudentFailed_Id] [uniqueidentifier] NOT NULL,[elt] [uniqueidentifier] NULL) ON [PRIMARY]
 CREATE TABLE [dbo].[Student]([Id] [uniqueidentifier] NOT NULL,[version] [datetime] NOT NULL,[firstName] [nvarchar](255) NULL,[lastName] [nvarchar](255) NULL,[hasGraduated] [bit] NULL,[credits] [int] NULL,[registrationSequence] [int] NULL, PRIMARY KEY CLUSTERED ([Id] ASC) ON [PRIMARY]) ON [PRIMARY]
 CREATE TABLE [dbo].[passedClasses]([StudentPassed_Id] [uniqueidentifier] NOT NULL, [elt] [uniqueidentifier] NULL) ON [PRIMARY]
 CREATE TABLE [dbo].[Registration]([aggregateRoot] [uniqueidentifier] NOT NULL,[Id] [int] NOT NULL,[version] [datetime] NOT NULL,[classId] [uniqueidentifier] NULL,[classCredits] [int] NULL, PRIMARY KEY CLUSTERED ([aggregateRoot] ASC, [Id] ASC) ON [PRIMARY]) ON [PRIMARY]
+
 ALTER TABLE [dbo].[failedClasses] ADD CONSTRAINT [failedClasses_to_Student] FOREIGN KEY([StudentFailed_Id]) REFERENCES [dbo].[Student] ([Id])
 ALTER TABLE [dbo].[passedClasses] ADD CONSTRAINT [passedClasses_to_Student] FOREIGN KEY([StudentPassed_Id]) REFERENCES [dbo].[Student] ([Id])
 ALTER TABLE [dbo].[Registration]  WITH CHECK ADD  CONSTRAINT [Registration_to_Student] FOREIGN KEY([aggregateRoot]) REFERENCES [dbo].[Student] ([Id])
\ No newline at end of file