nopCommerce 数据库初试化及数据操作

系统启动时执行任务：IStartupTask,启动时执行的任务主要是数据库的初始化和加载。

IStartupTask调用IEfDataProvider进行数据库的初始化。

IEfDataProvider,SqlCeDataProvider：获取数据连接工厂，不同类型数据库，连接工厂不同。

接口IStartupTask的实体类EfStartUpTask的实现如下：

 public class EfStartUpTask : IStartupTask
    {
        public void Execute()
        {
            var settings = EngineContext.Current.Resolve<DataSettings>();
            if (settings != null && settings.IsValid())
            {
                var provider = EngineContext.Current.Resolve<IEfDataProvider>();
                if (provider == null)
                    throw new NopException("No EfDataProvider found");
                provider.SetDatabaseInitializer();
            }
        }

        public int Order
        {
            //ensure that this task is run first
            get { return -; }
        }
    }

SqlCeInitializer，CreateCeDatabaseIfNotExists初始化数据库。

IDbContext，NopObjectContext系统数据库操作上下文。加载所有数据库映射类：EntityTypeConfiguration<TEntityType>。代码如下：

/// <summary>
/// DbModelBuilder 用于将 CLR 类映射到数据库架构。 此以代码为中心的方法称作“Code First”，可用于生成实体数据模型 (EDM) 模型。
/// </summary>
/// <param name="modelBuilder"></param>

protected override void OnModelCreating(DbModelBuilder modelBuilder)

        {
            //dynamically load all configuration
            //System.Type configType = typeof(LanguageMap);   //any of your configuration classes here
            //var typesToRegister = Assembly.GetAssembly(configType).GetTypes()

            var typesToRegister = Assembly.GetExecutingAssembly().GetTypes()
            .Where(type => !String.IsNullOrEmpty(type.Namespace))
            .Where(type => type.BaseType != null && type.BaseType.IsGenericType && type.BaseType.GetGenericTypeDefinition() == typeof(EntityTypeConfiguration<>));
            foreach (var type in typesToRegister)
            {
                dynamic configurationInstance = Activator.CreateInstance(type);
                modelBuilder.Configurations.Add(configurationInstance);
            }
            //...or do it manually below. For example,
            //modelBuilder.Configurations.Add(new LanguageMap());

            base.OnModelCreating(modelBuilder);
        }

此方法是继承自DbContext。并在系统启动时调用，建立数据表与实体的对应关系。

在类型依赖注册类Nop.Web.Framework.DependencyRegistrar中实现数据库工厂的创建、数据库的加载。如下代码：

 //data layer
            var dataSettingsManager = new DataSettingsManager();
            var dataProviderSettings = dataSettingsManager.LoadSettings();
            builder.Register(c => dataSettingsManager.LoadSettings()).As<DataSettings>();
            builder.Register(x => new EfDataProviderManager(x.Resolve<DataSettings>())).As<BaseDataProviderManager>().InstancePerDependency();

            builder.Register(x => x.Resolve<BaseDataProviderManager>().LoadDataProvider()).As<IDataProvider>().InstancePerDependency();

            if (dataProviderSettings != null && dataProviderSettings.IsValid())
            {
                var efDataProviderManager = new EfDataProviderManager(dataSettingsManager.LoadSettings());
                var dataProvider = efDataProviderManager.LoadDataProvider();
                dataProvider.InitConnectionFactory();

                builder.Register<IDbContext>(c => new NopObjectContext(dataProviderSettings.DataConnectionString)).InstancePerLifetimeScope();
            }
            else
            {
                builder.Register<IDbContext>(c => new NopObjectContext(dataSettingsManager.LoadSettings().DataConnectionString)).InstancePerLifetimeScope();
            }

            builder.RegisterGeneric(typeof(EfRepository<>)).As(typeof(IRepository<>)).InstancePerLifetimeScope();
            

接口IEfDataProvider 的实体类SqlServerDataProvider的数据库初始化方法如下：

  /// <summary>
        /// Set database initializer
        /// </summary>
        public virtual void SetDatabaseInitializer()
        {
            //pass some table names to ensure that we have nopCommerce 2.X installed
            var tablesToValidate = new[] { "Customer", "Discount", "Order", "Product", "ShoppingCartItem" };

            //custom commands (stored proedures, indexes)

            var customCommands = new List<string>();
            //use webHelper.MapPath instead of HostingEnvironment.MapPath which is not available in unit tests
            customCommands.AddRange(ParseCommands(HostingEnvironment.MapPath("~/App_Data/Install/SqlServer.Indexes.sql"), false));
            //use webHelper.MapPath instead of HostingEnvironment.MapPath which is not available in unit tests
            customCommands.AddRange(ParseCommands(HostingEnvironment.MapPath("~/App_Data/Install/SqlServer.StoredProcedures.sql"), false));

            var initializer = new CreateTablesIfNotExist<NopObjectContext>(tablesToValidate, customCommands.ToArray());
            Database.SetInitializer(initializer);
        }