Exemple #1
0
        static void Main(string[] args)
        {
            //-- Poor-man DI - build our dependencies by hand for this demo
            var dbContextScopeFactory   = new DbContextScopeFactory();
            var ambientDbContextLocator = new AmbientDbContextLocator();
            var userRepository          = new UserRepository(ambientDbContextLocator);

            var userCreationService    = new UserCreationService(dbContextScopeFactory, userRepository);
            var userQueryService       = new UserQueryService(dbContextScopeFactory, userRepository);
            var userEmailService       = new UserEmailService(dbContextScopeFactory);
            var userCreditScoreService = new UserCreditScoreService(dbContextScopeFactory);

            try
            {
                Console.WriteLine("This demo application will create a database named DbContextScopeDemo in the default SQL Server instance on localhost. Edit the connection string in UserManagementDbContext if you'd like to create it somewhere else.");
                Console.WriteLine("Press enter to start...");
                Console.ReadLine();

                //-- Demo of typical usage for read and writes
                Console.WriteLine("Creating a user called Mary...");
                var marysSpec = new UserCreationSpec("Mary", "*****@*****.**");
                userCreationService.CreateUser(marysSpec);
                Console.WriteLine("Done.\n");

                Console.WriteLine("Trying to retrieve our newly created user from the data store...");
                var mary = userQueryService.GetUser(marysSpec.Id);
                Console.WriteLine("OK. Persisted user: {0}", mary);

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of nested DbContextScopes
                Console.WriteLine("Creating 2 new users called John and Jeanne in an atomic transaction...");
                var johnSpec   = new UserCreationSpec("John", "*****@*****.**");
                var jeanneSpec = new UserCreationSpec("Jeanne", "*****@*****.**");
                userCreationService.CreateListOfUsers(johnSpec, jeanneSpec);
                Console.WriteLine("Done.\n");

                Console.WriteLine("Trying to retrieve our newly created users from the data store...");
                var createdUsers = userQueryService.GetUsers(johnSpec.Id, jeanneSpec.Id);
                Console.WriteLine("OK. Found {0} persisted users.", createdUsers.Count());

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of nested DbContextScopes in the face of an exception.
                // If any of the provided users failed to get persisted, none should get persisted.
                Console.WriteLine("Creating 2 new users called Julie and Marc in an atomic transaction. Will make the persistence of the second user fail intentionally in order to test the atomicity of the transaction...");
                var julieSpec = new UserCreationSpec("Julie", "*****@*****.**");
                var marcSpec  = new UserCreationSpec("Marc", "*****@*****.**");
                try
                {
                    userCreationService.CreateListOfUsersWithIntentionalFailure(julieSpec, marcSpec);
                    Console.WriteLine("Done.\n");
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.Message);
                    Console.WriteLine();
                }

                Console.WriteLine("Trying to retrieve our newly created users from the data store...");
                var maybeCreatedUsers = userQueryService.GetUsers(julieSpec.Id, marcSpec.Id);
                Console.WriteLine("Found {0} persisted users. If this number is 0, we're all good. If this number is not 0, we have a big problem.", maybeCreatedUsers.Count());

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of DbContextScope within an async flow
                Console.WriteLine("Trying to retrieve two users John and Jeanne sequentially in an asynchronous manner...");
                // We're going to block on the async task here as we don't have a choice. No risk of deadlocking in any case as console apps
                // don't have a synchronization context.
                var usersFoundAsync = userQueryService.GetTwoUsersAsync(johnSpec.Id, jeanneSpec.Id).Result;
                Console.WriteLine("OK. Found {0} persisted users.", usersFoundAsync.Count());

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of explicit database transaction.
                Console.WriteLine("Trying to retrieve user John within a READ UNCOMMITTED database transaction...");
                // You'll want to use SQL Profiler or Entity Framework Profiler to verify that the correct transaction isolation
                // level is being used.
                var userMaybeUncommitted = userQueryService.GetUserUncommitted(johnSpec.Id);
                Console.WriteLine("OK. User found: {0}", userMaybeUncommitted);

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of disabling the DbContextScope nesting behaviour in order to force the persistence of changes made to entities
                // This is a pretty advanced feature that you can safely ignore until you actually need it.
                Console.WriteLine("Will simulate sending a Welcome email to John...");

                using (var parentScope = dbContextScopeFactory.Create())
                {
                    var parentDbContext = parentScope.DbContexts.Get <UserManagementDbContext>();

                    // Load John in the parent DbContext
                    var john = parentDbContext.Users.Find(johnSpec.Id);
                    Console.WriteLine("Before calling SendWelcomeEmail(), john.WelcomeEmailSent = " + john.WelcomeEmailSent);

                    // Now call our SendWelcomeEmail() business logic service method, which will
                    // update John in a non-nested child context
                    userEmailService.SendWelcomeEmail(johnSpec.Id);

                    // Verify that we can see the modifications made to John by the SendWelcomeEmail() method
                    Console.WriteLine("After calling SendWelcomeEmail(), john.WelcomeEmailSent = " + john.WelcomeEmailSent);

                    // Note that even though we're not calling SaveChanges() in the parent scope here, the changes
                    // made to John by SendWelcomeEmail() will remain persisted in the database as SendWelcomeEmail()
                    // forced the creation of a new DbContextScope.
                }

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demonstration of DbContextScope and parallel programming
                Console.WriteLine("Calculating and storing the credit score of all users in the database in parallel...");
                userCreditScoreService.UpdateCreditScoreForAllUsers();
                Console.WriteLine("Done.");
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
            }

            Console.WriteLine();
            Console.WriteLine("The end.");
            Console.WriteLine("Press enter to exit...");
            Console.ReadLine();
        }
        static void Main(string[] args)
        {
            //-- Poor-man DI - build our dependencies by hand for this demo

            //var dbcontextFactory = new UserManagementDbContextFactory("data source=192.168.0.11;initial catalog=DbContextScopeDemo1;persist security info=True;user id=test;password=111111;MultipleActiveResultSets=True;App=EntityFramework");
            var dbcontextFactory = new DbContextFactory("server=127.0.0.1;port=3306;AutoEnlist=true;user id=root;password=jooge2012;persistsecurityinfo=True;database=test;oldguids=True");

            var dbContextScopeFactory = new DbContextScopeFactory(dbcontextFactory);

            var ambientDbContextLocator = new AmbientDbContextLocator();
            var userRepository          = new UserRepository(ambientDbContextLocator);

            var userCreationService    = new UserCreationService(dbContextScopeFactory, userRepository);
            var userQueryService       = new UserQueryService(dbContextScopeFactory, userRepository);
            var userEmailService       = new UserEmailService(dbContextScopeFactory);
            var userCreditScoreService = new UserCreditScoreService(dbContextScopeFactory);

            var userClassService = new UserClassService(dbContextScopeFactory);

            try
            {
                Console.WriteLine("This demo application will create a database named DbContextScopeDemo in the default SQL Server instance on localhost. Edit the connection string in UserManagementDbContext if you'd like to create it somewhere else.");
                Console.WriteLine("Press enter to start...");
                Console.ReadLine();


                Console.WriteLine("一个dbScope中使用2个DbContext 创建 a user and userClass Terry+English...");

                var user = new User
                {
                    Id               = Guid.NewGuid(),
                    Name             = "Terry",
                    Email            = "*****@*****.**",
                    WelcomeEmailSent = false,
                    CreatedOn        = DateTime.UtcNow
                };

                using (var dbContextScope = dbContextScopeFactory.Create())
                {
                    dbContextScope.DbContexts.Get <UserManagementDbContext>().Users.Add(user);

                    userClassService.CreateUserClass(user.Name, "English");

                    dbContextScope.SaveChanges();
                }

                Console.WriteLine("检查数据库应该有相应的记录user表 和 userClass表");
                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();


                Console.WriteLine("2个dbcontext 使用事务的情况,");
                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                user = new User
                {
                    Id               = Guid.NewGuid(),
                    Name             = "Mark",
                    Email            = "*****@*****.**",
                    WelcomeEmailSent = false,
                    CreatedOn        = DateTime.UtcNow
                };


                int rowCount = 0;
                try
                {
                    using (var s = new TransactionScope())
                    {
                        using (var dbContextScope = dbContextScopeFactory.Create())
                        {
                            dbContextScope.DbContexts.Get <UserManagementDbContext>().Users.Add(user);
                            dbContextScope.SaveChanges();
                        }

                        rowCount = userClassService.GetRowCount();
                        userClassService.CreateUserClass(user.Name, "English");

                        throw new Exception("模拟错误");

                        s.Complete();
                    }
                }
                catch
                {
                }

                var tempUsers = userQueryService.GetUsers(user.Id);
                Console.WriteLine("Found {0} persisted users. If this number is 0, we're all good. If this number is not 0, we have a big problem.", tempUsers.Count());

                if (rowCount == userClassService.GetRowCount())
                {
                    Console.WriteLine("userClass表的数量没有变化,是正确的,如果变化了就不对了");
                }
                else
                {
                    Console.WriteLine("userClass表的数量变化了,是不对的。");
                }


                //-- Demo of typical usage for read and writes
                Console.WriteLine("Creating a user called Mary...");
                var marysSpec = new UserCreationSpec("Mary", "*****@*****.**");
                userCreationService.CreateUser(marysSpec);
                Console.WriteLine("Done.\n");

                Console.WriteLine("Trying to retrieve our newly created user from the data store...");
                var mary = userQueryService.GetUser(marysSpec.Id);
                Console.WriteLine("OK. Persisted user: {0}", mary);

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of nested DbContextScopes
                Console.WriteLine("Creating 2 new users called John and Jeanne in an atomic transaction...");
                var johnSpec   = new UserCreationSpec("John", "*****@*****.**");
                var jeanneSpec = new UserCreationSpec("Jeanne", "*****@*****.**");
                userCreationService.CreateListOfUsers(johnSpec, jeanneSpec);
                Console.WriteLine("Done.\n");

                Console.WriteLine("Trying to retrieve our newly created users from the data store...");
                var createdUsers = userQueryService.GetUsers(johnSpec.Id, jeanneSpec.Id);
                Console.WriteLine("OK. Found {0} persisted users.", createdUsers.Count());

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of nested DbContextScopes in the face of an exception.
                // If any of the provided users failed to get persisted, none should get persisted.
                Console.WriteLine("Creating 2 new users called Julie and Marc in an atomic transaction. Will make the persistence of the second user fail intentionally in order to test the atomicity of the transaction...");
                var julieSpec = new UserCreationSpec("Julie", "*****@*****.**");
                var marcSpec  = new UserCreationSpec("Marc", "*****@*****.**");
                try
                {
                    userCreationService.CreateListOfUsersWithIntentionalFailure(julieSpec, marcSpec);
                    Console.WriteLine("Done.\n");
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.Message);
                    Console.WriteLine();
                }

                Console.WriteLine("Trying to retrieve our newly created users from the data store...");
                var maybeCreatedUsers = userQueryService.GetUsers(julieSpec.Id, marcSpec.Id);
                Console.WriteLine("Found {0} persisted users. If this number is 0, we're all good. If this number is not 0, we have a big problem.", maybeCreatedUsers.Count());

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of DbContextScope within an async flow
                Console.WriteLine("Trying to retrieve two users John and Jeanne sequentially in an asynchronous manner...");
                // We're going to block on the async task here as we don't have a choice. No risk of deadlocking in any case as console apps
                // don't have a synchronization context.
                var usersFoundAsync = userQueryService.GetTwoUsersAsync(johnSpec.Id, jeanneSpec.Id).Result;
                Console.WriteLine("OK. Found {0} persisted users.", usersFoundAsync.Count());

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of explicit database transaction.
                Console.WriteLine("Trying to retrieve user John within a READ UNCOMMITTED database transaction...");
                // You'll want to use SQL Profiler or Entity Framework Profiler to verify that the correct transaction isolation
                // level is being used.
                var userMaybeUncommitted = userQueryService.GetUserUncommitted(johnSpec.Id);
                Console.WriteLine("OK. User found: {0}", userMaybeUncommitted);

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of disabling the DbContextScope nesting behaviour in order to force the persistence of changes made to entities
                // This is a pretty advanced feature that you can safely ignore until you actually need it.
                Console.WriteLine("Will simulate sending a Welcome email to John...");

                using (var parentScope = dbContextScopeFactory.Create())
                {
                    var parentDbContext = parentScope.DbContexts.Get <UserManagementDbContext>();

                    // Load John in the parent DbContext
                    var john = parentDbContext.Users.Find(johnSpec.Id);
                    Console.WriteLine("Before calling SendWelcomeEmail(), john.WelcomeEmailSent = " + john.WelcomeEmailSent);

                    // Now call our SendWelcomeEmail() business logic service method, which will
                    // update John in a non-nested child context
                    userEmailService.SendWelcomeEmail(johnSpec.Id);

                    // Verify that we can see the modifications made to John by the SendWelcomeEmail() method
                    Console.WriteLine("After calling SendWelcomeEmail(), john.WelcomeEmailSent = " + john.WelcomeEmailSent);

                    // Note that even though we're not calling SaveChanges() in the parent scope here, the changes
                    // made to John by SendWelcomeEmail() will remain persisted in the database as SendWelcomeEmail()
                    // forced the creation of a new DbContextScope.
                }

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demonstration of DbContextScope and parallel programming
                Console.WriteLine("Calculating and storing the credit score of all users in the database in parallel...");
                userCreditScoreService.UpdateCreditScoreForAllUsers();
                Console.WriteLine("Done.");

                Console.WriteLine("Trying to retrieve users by where clause.");
                var users = userQueryService.GetUserByWhereClause(" WelcomeEmailSent = 1 ");
                Console.WriteLine("OK. WelcomeEmailSent user count: {0}", users.Count());


                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
            }

            Console.WriteLine();
            Console.WriteLine("The end.");
            Console.WriteLine("Press enter to exit...");
            Console.ReadLine();
        }
Exemple #3
0
        private static void Main(string[] args)
        {
            //-- Poor-man DI - build our dependencies by hand for this demo
            ISessionFactory        sessionFactory        = UserSessionFactory.CreateSessionFactory();
            ISessionScopeFactory   sessionScopeFactory   = new SessionScopeFactory(sessionFactory);
            IAmbientSessionLocator ambientSessionLocator = new AmbientSessionLocator();
            IUserRepository        userRepository        = new UserRepository(ambientSessionLocator);

            var userCreationService    = new UserCreationService(sessionScopeFactory, userRepository);
            var userQueryService       = new UserQueryService(sessionScopeFactory, userRepository);
            var userCreditScoreService = new UserCreditScoreService(sessionScopeFactory);

            try
            {
                Console.WriteLine("This demo application will create a database named NH in the LocalDB SQL Server instance on localhost. Edit the connection string in UserSessionFactory if you'd like to create it somewhere else.");
                Console.WriteLine("Press enter to start...");
                Console.ReadLine();

                //-- Demo of typical usage for read and writes
                Console.WriteLine("Creating a user called Mary...");
                var marySpec = new UserCreationSpec("Mary", "*****@*****.**");
                userCreationService.CreateUser(marySpec);
                Console.WriteLine("Done.\n");

                Console.WriteLine("Trying to retrieve our newly created user from the data store...");
                var mary = userQueryService.GetUser(marySpec.Id);
                Console.WriteLine("OK. Persisted user: {0}", mary);

                Console.WriteLine("Trying to retrieve our newly created user from the data store via a repository...");
                var maryViaRepo = userQueryService.GetUserViaRepository(marySpec.Id);
                Console.WriteLine("OK. Persisted user: {0}", maryViaRepo);

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of nested SessionScopes
                Console.WriteLine("Creating 2 new users called John and Jeanne in an atomic transaction...");
                var johnSpec   = new UserCreationSpec("John", "*****@*****.**");
                var jeanneSpec = new UserCreationSpec("Jeanne", "*****@*****.**");
                userCreationService.CreateListOfUsers(johnSpec, jeanneSpec);
                Console.WriteLine("Done.\n");

                Console.WriteLine("Trying to retrieve our newly created users from the data store...");
                var createdUsers = userQueryService.GetUsers(johnSpec.Id, jeanneSpec.Id);
                Console.WriteLine("OK. Found {0} persisted users.", createdUsers.Count());

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of nested SessionScopes in the face of an exception.
                // If any of the provided users failed to get persisted, none should get persisted.
                Console.WriteLine("Creating 2 new users called Julie and Marc in an atomic transaction. Will make the persistence of the second user fail intentionally in order to test the atomicity of the transaction...");
                var julieSpec = new UserCreationSpec("Julie", "*****@*****.**");
                var marcSpec  = new UserCreationSpec("Marc", "*****@*****.**");
                try
                {
                    userCreationService.CreateListOfUsersWithIntentionalFailure(julieSpec, marcSpec);
                    Console.WriteLine("Done.\n");
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.Message);
                    Console.WriteLine();
                }

                Console.WriteLine("Trying to retrieve our newly created users from the data store...");
                var maybeCreatedUsers = userQueryService.GetUsers(julieSpec.Id, marcSpec.Id);
                Console.WriteLine("Found {0} persisted users. If this number is 0, we're all good. If this number is not 0, we have a big problem.", maybeCreatedUsers.Count());

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of explicit database transaction isolation level.
                Console.WriteLine("Trying to retrieve user John within a READ UNCOMMITTED database transaction...");
                // You'll want to use SQL Profiler or Entity Framework Profiler to verify that the correct transaction isolation
                // level is being used.
                var userMaybeUncommitted = userQueryService.GetUserUncommitted(johnSpec.Id);
                Console.WriteLine("OK. User found: {0}", userMaybeUncommitted);

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demonstration of SessionScope and parallel programming
                Console.WriteLine("Calculating and storing the credit score of all users in the database in parallel...");
                userCreditScoreService.UpdateCreditScoreForAllUsers();
                Console.WriteLine("Done.");
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
            }

            Console.WriteLine();
            Console.WriteLine("The end.");
            Console.WriteLine("Press enter to exit...");
            Console.ReadLine();
        }
        static void Main(string[] args)
        {
            //-- Poor-man DI - build our dependencies by hand for this demo
            IDbScopeFactory dbScopeFactory = new EntityFrameworkScopeFactory();
            IAmbientDbLocator ambientDbLocator = new EntityFrameworkAmbientLocator();
            IUserRepository userRepository = new UserRepository(ambientDbLocator);

            var userCreationService = new UserCreationService(dbScopeFactory, userRepository);
            var userQueryService = new UserQueryService(dbScopeFactory, userRepository);
            var userEmailService = new UserEmailService(dbScopeFactory);
            var userCreditScoreService = new UserCreditScoreService(dbScopeFactory);

            try
            {
                Console.WriteLine("This demo application will create a database named DbContextScopeDemo in the default SQL Server instance on localhost. Edit the connection string in UserManagementDbContext if you'd like to create it somewhere else.");
                Console.WriteLine("Press enter to start...");
                Console.ReadLine();

                //-- Demo of typical usage for read and writes
                Console.WriteLine("Creating a user called Mary...");
                var marysSpec = new UserCreationSpec("Mary", "*****@*****.**");
                userCreationService.CreateUser(marysSpec);
                Console.WriteLine("Done.\n");

                Console.WriteLine("Trying to retrieve our newly created user from the data store...");
                var mary = userQueryService.GetUser(marysSpec.Id);
                Console.WriteLine("OK. Persisted user: {0}", mary);

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of nested DbScopes
                Console.WriteLine("Creating 2 new users called John and Jeanne in an atomic transaction...");
                var johnSpec = new UserCreationSpec("John", "*****@*****.**");
                var jeanneSpec = new UserCreationSpec("Jeanne", "*****@*****.**");
                userCreationService.CreateListOfUsers(johnSpec, jeanneSpec);
                Console.WriteLine("Done.\n");

                Console.WriteLine("Trying to retrieve our newly created users from the data store...");
                var createdUsers = userQueryService.GetUsers(johnSpec.Id, jeanneSpec.Id);
                Console.WriteLine("OK. Found {0} persisted users.", createdUsers.Count());

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of nested DbScopes in the face of an exception.
                // If any of the provided users failed to get persisted, none should get persisted.
                Console.WriteLine("Creating 2 new users called Julie and Marc in an atomic transaction. Will make the persistence of the second user fail intentionally in order to test the atomicity of the transaction...");
                var julieSpec = new UserCreationSpec("Julie", "*****@*****.**");
                var marcSpec = new UserCreationSpec("Marc", "*****@*****.**");
                try
                {
                    userCreationService.CreateListOfUsersWithIntentionalFailure(julieSpec, marcSpec);
                    Console.WriteLine("Done.\n");
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.Message);
                    Console.WriteLine();
                }

                Console.WriteLine("Trying to retrieve our newly created users from the data store...");
                var maybeCreatedUsers = userQueryService.GetUsers(julieSpec.Id, marcSpec.Id);
                Console.WriteLine("Found {0} persisted users. If this number is 0, we're all good. If this number is not 0, we have a big problem.", maybeCreatedUsers.Count());

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of DbScope within an async flow
                Console.WriteLine("Trying to retrieve two users John and Jeanne sequentially in an asynchronous manner...");
                // We're going to block on the async task here as we don't have a choice. No risk of deadlocking in any case as console apps
                // don't have a synchronization context.
                var usersFoundAsync = userQueryService.GetTwoUsersAsync(johnSpec.Id, jeanneSpec.Id).Result;
                Console.WriteLine("OK. Found {0} persisted users.", usersFoundAsync.Count());

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of explicit database transaction.
                Console.WriteLine("Trying to retrieve user John within a READ UNCOMMITTED database transaction...");
                // You'll want to use SQL Profiler or Entity Framework Profiler to verify that the correct transaction isolation
                // level is being used.
                var userMaybeUncommitted = userQueryService.GetUserUncommitted(johnSpec.Id);
                Console.WriteLine("OK. User found: {0}", userMaybeUncommitted);

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demo of disabling the DbScope nesting behaviour in order to force the persistence of changes made to entities
                // This is a pretty advanced feature that you can safely ignore until you actually need it.
                Console.WriteLine("Will simulate sending a Welcome email to John...");

                using (var parentScope = dbScopeFactory.Create())
                {
                    var parentDbContext = parentScope.Get<UserManagementDbContext>();

                    // Load John in the parent DbContext
                    var john = parentDbContext.Users.Find(johnSpec.Id);
                    Console.WriteLine("Before calling SendWelcomeEmail(), john.WelcomeEmailSent = " + john.WelcomeEmailSent);

                    // Now call our SendWelcomeEmail() business logic service method, which will
                    // update John in a non-nested child context
                    userEmailService.SendWelcomeEmail(johnSpec.Id);

                    // Verify that we can see the modifications made to John by the SendWelcomeEmail() method
                    Console.WriteLine("After calling SendWelcomeEmail(), john.WelcomeEmailSent = " + john.WelcomeEmailSent);

                    // Note that even though we're not calling SaveChanges() in the parent scope here, the changes
                    // made to John by SendWelcomeEmail() will remain persisted in the database as SendWelcomeEmail()
                    // forced the creation of a new DbScope.
                }

                Console.WriteLine("Press enter to continue...");
                Console.ReadLine();

                //-- Demonstration of DbScope and parallel programming
                Console.WriteLine("Calculating and storing the credit score of all users in the database in parallel...");
                userCreditScoreService.UpdateCreditScoreForAllUsers();
                Console.WriteLine("Done.");
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
            }

            Console.WriteLine();
            Console.WriteLine("The end.");
            Console.WriteLine("Press enter to exit...");
            Console.ReadLine();
        }