و در حالت کلی، بله. مبحثی هست که اخیرا اضافه شده به نام DB Migration که در چند قسمت بعد به آن خواهیم رسید.
EF Code First #2
و در حالت کلی، بله. مبحثی هست که اخیرا اضافه شده به نام DB Migration که در چند قسمت بعد به آن خواهیم رسید.
var sequence = new[] { 12, 3, -4, 7 }.ToObservable(); var runningSum = sequence.Scan((accumulator, value) => { Console.WriteLine("accumulator {0}", accumulator); Console.WriteLine("value {0}", value); return accumulator + value; }); runningSum.Subscribe(result => Console.WriteLine("result {0}\n", result));
result 12 accumulator 12 value 3 result 15 accumulator 15 value -4 result 11 accumulator 11 value 7 result 18
var runningSum = sequence.Scan(seed: 10, accumulator: (accumulator, value) =>
var sequence = Enumerable.Range(1, 200) .ToObservable() .Buffer(count: 10); sequence.Subscribe(onNext: numbers => { Console.WriteLine(numbers.Sum()); });
var sequence = Enumerable.Range(1, 200) .ToObservable() .Buffer(timeSpan: TimeSpan.FromSeconds(2));
var sequence = Enumerable.Range(1, 200) .ToObservable() .Window(timeSpan: TimeSpan.FromSeconds(2)); sequence.Subscribe(onNext: numbers => { numbers.Subscribe(onNext: number => Console.WriteLine(number)); });
var sequence = Enumerable.Range(1, 200) .ToObservable() .Window(10); sequence.Subscribe(onNext: numbers => { numbers.Sum().Subscribe(onNext: number => Console.WriteLine(number)); });
using System; namespace IndexedProperties { public class Data { private int[] _localArray; private ArrayIndexer _arrayIndexer; public Data() { _localArray = new int[10]; for (int i = 0; i < 10; i++) _localArray[i] = i + 1; _arrayIndexer = new ArrayIndexer(this); } public ArrayIndexer Number { get { return _arrayIndexer; } } public class ArrayIndexer { private Data _arrayOwner; public ArrayIndexer(Data arrayOwner) { _arrayOwner = arrayOwner; } public int this[int index] { get { return _arrayOwner._localArray[index]; } } public int Length { get { return _arrayOwner._localArray.Length; } } } } class Program { static void Main(string[] args) { var data = new Data(); for (int i = 0; i < 10; i++) Console.WriteLine(data.Number[i]); } } }
Northwind Traders is a sample application built using ASP.NET Core and Entity Framework Core. The architecture and design of the project is explained in the video:
Clean Architecture with ASP.NET Core 2.1using System.ComponentModel.DataAnnotations.Schema; namespace BlazorServer.Entities { public class HotelRoomImage { public int Id { get; set; } public string RoomImageUrl { get; set; } [ForeignKey("RoomId")] public virtual HotelRoom HotelRoom { get; set; } public int RoomId { get; set; } } }
namespace BlazorServer.Entities { public class HotelRoom { // ... public virtual ICollection<HotelRoomImage> HotelRoomImages { get; set; } } }
namespace BlazorServer.DataAccess { public class ApplicationDbContext : DbContext { public DbSet<HotelRoomImage> HotelRoomImages { get; set; } // ... } }
dotnet tool update --global dotnet-ef --version 5.0.3 dotnet build dotnet ef migrations --startup-project ../BlazorServer.App/ add Init --context ApplicationDbContext dotnet ef --startup-project ../BlazorServer.App/ database update --context ApplicationDbContext
namespace BlazorServer.Models { public class HotelRoomImageDTO { public int Id { get; set; } public int RoomId { get; set; } public string RoomImageUrl { get; set; } } }
using AutoMapper; using BlazorServer.Entities; namespace BlazorServer.Models.Mappings { public class MappingProfile : Profile { public MappingProfile() { // ... CreateMap<HotelRoomImageDTO, HotelRoomImage>().ReverseMap(); // two-way mapping } } }
namespace BlazorServer.Services { public interface IHotelRoomImageService { Task<int> CreateHotelRoomImageAsync(HotelRoomImageDTO imageDTO); Task<int> DeleteHotelRoomImageByImageIdAsync(int imageId); Task<int> DeleteHotelRoomImageByRoomIdAsync(int roomId); Task<List<HotelRoomImageDTO>> GetHotelRoomImagesAsync(int roomId); } }
namespace BlazorServer.Services { public class HotelRoomImageService : IHotelRoomImageService { private readonly ApplicationDbContext _dbContext; private readonly IMapper _mapper; private readonly IConfigurationProvider _mapperConfiguration; public HotelRoomImageService(ApplicationDbContext dbContext, IMapper mapper) { _dbContext = dbContext ?? throw new ArgumentNullException(nameof(dbContext)); _mapper = mapper ?? throw new ArgumentNullException(nameof(mapper)); _mapperConfiguration = mapper.ConfigurationProvider; } public async Task<int> CreateHotelRoomImageAsync(HotelRoomImageDTO imageDTO) { var image = _mapper.Map<HotelRoomImage>(imageDTO); await _dbContext.HotelRoomImages.AddAsync(image); return await _dbContext.SaveChangesAsync(); } public async Task<int> DeleteHotelRoomImageByImageIdAsync(int imageId) { var image = await _dbContext.HotelRoomImages.FindAsync(imageId); _dbContext.HotelRoomImages.Remove(image); return await _dbContext.SaveChangesAsync(); } public async Task<int> DeleteHotelRoomImageByRoomIdAsync(int roomId) { var imageList = await _dbContext.HotelRoomImages.Where(x => x.RoomId == roomId).ToListAsync(); _dbContext.HotelRoomImages.RemoveRange(imageList); return await _dbContext.SaveChangesAsync(); } public Task<List<HotelRoomImageDTO>> GetHotelRoomImagesAsync(int roomId) { return _dbContext.HotelRoomImages .Where(x => x.RoomId == roomId) .ProjectTo<HotelRoomImageDTO>(_mapperConfiguration) .ToListAsync(); } } }
namespace BlazorServer.App { public class Startup { public void ConfigureServices(IServiceCollection services) { services.AddScoped<IHotelRoomImageService, HotelRoomImageService>(); // ...
using Microsoft.AspNetCore.Components.Forms; using System.Threading.Tasks; namespace BlazorServer.Services { public interface IFileUploadService { void DeleteFile(string fileName, string webRootPath, string uploadFolder); Task<string> UploadFileAsync(IBrowserFile inputFile, string webRootPath, string uploadFolder); } }
using Microsoft.AspNetCore.Components.Forms; using System; using System.IO; using System.Threading.Tasks; namespace BlazorServer.Services { public class FileUploadService : IFileUploadService { private const int MaxBufferSize = 0x10000; public void DeleteFile(string fileName, string webRootPath, string uploadFolder) { var path = Path.Combine(webRootPath, uploadFolder, fileName); if (File.Exists(path)) { File.Delete(path); } } public async Task<string> UploadFileAsync(IBrowserFile inputFile, string webRootPath, string uploadFolder) { createUploadDir(webRootPath, uploadFolder); var (fileName, imageFilePath) = getOutputFileInfo(inputFile, webRootPath, uploadFolder); using (var outputFileStream = new FileStream( imageFilePath, FileMode.Create, FileAccess.Write, FileShare.None, MaxBufferSize, useAsync: true)) { using var inputStream = inputFile.OpenReadStream(); await inputStream.CopyToAsync(outputFileStream); } return $"{uploadFolder}/{fileName}"; } private static (string FileName, string FilePath) getOutputFileInfo( IBrowserFile inputFile, string webRootPath, string uploadFolder) { var fileName = Path.GetFileName(inputFile.Name); var imageFilePath = Path.Combine(webRootPath, uploadFolder, fileName); if (File.Exists(imageFilePath)) { var fileNameWithoutExtension = Path.GetFileNameWithoutExtension(fileName); var fileExtension = Path.GetExtension(fileName); fileName = $"{fileNameWithoutExtension}-{Guid.NewGuid()}{fileExtension}"; imageFilePath = Path.Combine(webRootPath, uploadFolder, fileName); } return (fileName, imageFilePath); } private static void createUploadDir(string webRootPath, string uploadFolder) { var folderDirectory = Path.Combine(webRootPath, uploadFolder); if (!Directory.Exists(folderDirectory)) { Directory.CreateDirectory(folderDirectory); } } } }
<Project Sdk="Microsoft.NET.Sdk"> <ItemGroup> <PackageReference Include="Microsoft.AspNetCore.Components.Web" Version="5.0.3" /> </ItemGroup> </Project>
namespace BlazorServer.App { public class Startup { public void ConfigureServices(IServiceCollection services) { services.AddScoped<IFileUploadService, FileUploadService>(); // ...
فرض کنید میخواهیم از سرویسهای REST-based برای انجام عملیات CRUD روی یک Object graph استفاده کنیم. همچنین میخواهیم رویکردی در سمت کلاینت برای بروز رسانی کلاس موجودیتها پیاده سازی کنیم که قابل استفاده مجدد (reusable) باشد. علاوه بر این دسترسی دادهها توسط مدل Code-First انجام میشود.
در مثال جاری یک اپلیکیشن کلاینت (برنامه کنسول) خواهیم داشت که سرویسهای ارائه شده توسط پروژه Web API را فراخوانی میکند. هر پروژه در یک Solution مجزا قرار دارد، با این کار یک محیط n-Tier را شبیه سازی میکنیم.
مدل زیر را در نظر بگیرید.
همانطور که میبینید مدل مثال جاری مشتریان و شماره تماس آنها را ارائه میکند. میخواهیم مدلها و کد دسترسی به دادهها را در یک سرویس Web API پیاده سازی کنیم تا هر کلاینتی که به HTTP دسترسی دارد بتواند از آن استفاده کند. برای ساخت سرویس مذکور مراحل زیر را دنبال کنید.
public abstract class BaseEntity { protected BaseEntity() { TrackingState = TrackingState.Nochange; } public TrackingState TrackingState { get; set; } } public enum TrackingState { Nochange, Add, Update, Remove, }
public class Customer : BaseEntity { public int CustomerId { get; set; } public string Name { get; set; } public string Company { get; set; } public virtual ICollection<Phone> Phones { get; set; } } public class Phone : BaseEntity { public int PhoneId { get; set; } public string Number { get; set; } public string PhoneType { get; set; } public int CustomerId { get; set; } public virtual Customer Customer { get; set; } }
public class Recipe4Context : DbContext { public Recipe4Context() : base("Recipe4ConnectionString") { } public DbSet<Customer> Customers { get; set; } public DbSet<Phone> Phones { get; set; } protected override void OnModelCreating(DbModelBuilder modelBuilder) { // Do not persist TrackingState property to data store // This property is used internally to track state of // disconnected entities across service boundaries. // Leverage the Custom Code First Conventions features from Entity Framework 6. // Define a convention that performs a configuration for every entity // that derives from a base entity class. modelBuilder.Types<BaseEntity>().Configure(x => x.Ignore(y => y.TrackingState)); modelBuilder.Entity<Customer>().ToTable("Customers"); modelBuilder.Entity<Phone>().ToTable("Phones"); } }
<connectionStrings> <add name="Recipe4ConnectionString" connectionString="Data Source=.; Initial Catalog=EFRecipes; Integrated Security=True; MultipleActiveResultSets=True" providerName="System.Data.SqlClient" /> </connectionStrings>
protected void Application_Start() { // Disable Entity Framework Model Compatibilty Database.SetInitializer<Recipe1Context>(null); // The bidirectional navigation properties between related entities // create a self-referencing loop that breaks Web API's effort to // serialize the objects as JSON. By default, Json.NET is configured // to error when a reference loop is detected. To resolve problem, // simply configure JSON serializer to ignore self-referencing loops. GlobalConfiguration.Configuration.Formatters.JsonFormatter .SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore; ... }
public static EntityState Set(TrackingState trackingState) { switch (trackingState) { case TrackingState.Add: return EntityState.Added; case TrackingState.Update: return EntityState.Modified; case TrackingState.Remove: return EntityState.Deleted; default: return EntityState.Unchanged; } }
public class CustomerController : ApiController { // GET api/customer public IEnumerable<Customer> Get() { using (var context = new Recipe4Context()) { return context.Customers.Include(x => x.Phones).ToList(); } } // GET api/customer/5 public Customer Get(int id) { using (var context = new Recipe4Context()) { return context.Customers.Include(x => x.Phones).FirstOrDefault(x => x.CustomerId == id); } } [ActionName("Update")] public HttpResponseMessage UpdateCustomer(Customer customer) { using (var context = new Recipe4Context()) { // Add object graph to context setting default state of 'Added'. // Adding parent to context automatically attaches entire graph // (parent and child entities) to context and sets state to 'Added' // for all entities. context.Customers.Add(customer); foreach (var entry in context.ChangeTracker.Entries<BaseEntity>()) { entry.State = EntityStateFactory.Set(entry.Entity.TrackingState); if (entry.State == EntityState.Modified) { // For entity updates, we fetch a current copy of the entity // from the database and assign the values to the orginal values // property from the Entry object. OriginalValues wrap a dictionary // that represents the values of the entity before applying changes. // The Entity Framework change tracker will detect // differences between the current and original values and mark // each property and the entity as modified. Start by setting // the state for the entity as 'Unchanged'. entry.State = EntityState.Unchanged; var databaseValues = entry.GetDatabaseValues(); entry.OriginalValues.SetValues(databaseValues); } } context.SaveChanges(); } return Request.CreateResponse(HttpStatusCode.OK, customer); } [HttpDelete] [ActionName("Cleanup")] public HttpResponseMessage Cleanup() { using (var context = new Recipe4Context()) { context.Database.ExecuteSqlCommand("delete from phones"); context.Database.ExecuteSqlCommand("delete from customers"); return Request.CreateResponse(HttpStatusCode.OK); } } }
internal class Program { private HttpClient _client; private Customer _bush, _obama; private Phone _whiteHousePhone, _bushMobilePhone, _obamaMobilePhone; private HttpResponseMessage _response; private static void Main() { Task t = Run(); t.Wait(); Console.WriteLine("\nPress <enter> to continue..."); Console.ReadLine(); } private static async Task Run() { var program = new Program(); program.ServiceSetup(); // do not proceed until clean-up completes await program.CleanupAsync(); program.CreateFirstCustomer(); // do not proceed until customer is added await program.AddCustomerAsync(); program.CreateSecondCustomer(); // do not proceed until customer is added await program.AddSecondCustomerAsync(); // do not proceed until customer is removed await program.RemoveFirstCustomerAsync(); // do not proceed until customers are fetched await program.FetchCustomersAsync(); } private void ServiceSetup() { // set up infrastructure for Web API call _client = new HttpClient { BaseAddress = new Uri("http://localhost:62799/") }; // add Accept Header to request Web API content negotiation to return resource in JSON format _client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue ("application/json")); } private async Task CleanupAsync() { // call the cleanup method from the service _response = await _client.DeleteAsync("api/customer/cleanup/"); } private void CreateFirstCustomer() { // create customer #1 and two phone numbers _bush = new Customer { Name = "George Bush", Company = "Ex President", // set tracking state to 'Add' to generate a SQL Insert statement TrackingState = TrackingState.Add, }; _whiteHousePhone = new Phone { Number = "212 222-2222", PhoneType = "White House Red Phone", // set tracking state to 'Add' to generate a SQL Insert statement TrackingState = TrackingState.Add, }; _bushMobilePhone = new Phone { Number = "212 333-3333", PhoneType = "Bush Mobile Phone", // set tracking state to 'Add' to generate a SQL Insert statement TrackingState = TrackingState.Add, }; _bush.Phones.Add(_whiteHousePhone); _bush.Phones.Add(_bushMobilePhone); } private async Task AddCustomerAsync() { // construct call to invoke UpdateCustomer action method in Web API service _response = await _client.PostAsync("api/customer/updatecustomer/", _bush, new JsonMediaTypeFormatter()); if (_response.IsSuccessStatusCode) { // capture newly created customer entity from service, which will include // database-generated Ids for all entities _bush = await _response.Content.ReadAsAsync<Customer>(); _whiteHousePhone = _bush.Phones.FirstOrDefault(x => x.CustomerId == _bush.CustomerId); _bushMobilePhone = _bush.Phones.FirstOrDefault(x => x.CustomerId == _bush.CustomerId); Console.WriteLine("Successfully created Customer {0} and {1} Phone Numbers(s)", _bush.Name, _bush.Phones.Count); foreach (var phoneType in _bush.Phones) { Console.WriteLine("Added Phone Type: {0}", phoneType.PhoneType); } } else Console.WriteLine("{0} ({1})", (int)_response.StatusCode, _response.ReasonPhrase); } private void CreateSecondCustomer() { // create customer #2 and phone numbers _obama = new Customer { Name = "Barack Obama", Company = "President", // set tracking state to 'Add' to generate a SQL Insert statement TrackingState = TrackingState.Add, }; _obamaMobilePhone = new Phone { Number = "212 444-4444", PhoneType = "Obama Mobile Phone", // set tracking state to 'Add' to generate a SQL Insert statement TrackingState = TrackingState.Add, }; // set tracking state to 'Modifed' to generate a SQL Update statement _whiteHousePhone.TrackingState = TrackingState.Update; _obama.Phones.Add(_obamaMobilePhone); _obama.Phones.Add(_whiteHousePhone); } private async Task AddSecondCustomerAsync() { // construct call to invoke UpdateCustomer action method in Web API service _response = await _client.PostAsync("api/customer/updatecustomer/", _obama, new JsonMediaTypeFormatter()); if (_response.IsSuccessStatusCode) { // capture newly created customer entity from service, which will include // database-generated Ids for all entities _obama = await _response.Content.ReadAsAsync<Customer>(); _whiteHousePhone = _bush.Phones.FirstOrDefault(x => x.CustomerId == _obama.CustomerId); _bushMobilePhone = _bush.Phones.FirstOrDefault(x => x.CustomerId == _obama.CustomerId); Console.WriteLine("Successfully created Customer {0} and {1} Phone Numbers(s)", _obama.Name, _obama.Phones.Count); foreach (var phoneType in _obama.Phones) { Console.WriteLine("Added Phone Type: {0}", phoneType.PhoneType); } } else Console.WriteLine("{0} ({1})", (int)_response.StatusCode, _response.ReasonPhrase); } private async Task RemoveFirstCustomerAsync() { // remove George Bush from underlying data store. // first, fetch George Bush entity, demonstrating a call to the // get action method on the service while passing a parameter var query = "api/customer/" + _bush.CustomerId; _response = _client.GetAsync(query).Result; if (_response.IsSuccessStatusCode) { _bush = await _response.Content.ReadAsAsync<Customer>(); // set tracking state to 'Remove' to generate a SQL Delete statement _bush.TrackingState = TrackingState.Remove; // must also remove bush's mobile number -- must delete child before removing parent foreach (var phoneType in _bush.Phones) { // set tracking state to 'Remove' to generate a SQL Delete statement phoneType.TrackingState = TrackingState.Remove; } // construct call to remove Bush from underlying database table _response = await _client.PostAsync("api/customer/updatecustomer/", _bush, new JsonMediaTypeFormatter()); if (_response.IsSuccessStatusCode) { Console.WriteLine("Removed {0} from database", _bush.Name); foreach (var phoneType in _bush.Phones) { Console.WriteLine("Remove {0} from data store", phoneType.PhoneType); } } else Console.WriteLine("{0} ({1})", (int)_response.StatusCode, _response.ReasonPhrase); } else { Console.WriteLine("{0} ({1})", (int)_response.StatusCode, _response.ReasonPhrase); } } private async Task FetchCustomersAsync() { // finally, return remaining customers from underlying data store _response = await _client.GetAsync("api/customer/"); if (_response.IsSuccessStatusCode) { var customers = await _response.Content.ReadAsAsync<IEnumerable<Customer>>(); foreach (var customer in customers) { Console.WriteLine("Customer {0} has {1} Phone Numbers(s)", customer.Name, customer.Phones.Count()); foreach (var phoneType in customer.Phones) { Console.WriteLine("Phone Type: {0}", phoneType.PhoneType); } } } else { Console.WriteLine("{0} ({1})", (int)_response.StatusCode, _response.ReasonPhrase); } } }
اگر اپلیکیشن کلاینت را اجرا کنید با خروجی زیر مواجه خواهید شد.
با اجرای اپلیکیشن Web API شروع کنید. این اپلیکیشن یک MVC Web Controller دارد که پس از اجرا شما را به صفحه خانه هدایت میکند. در این مرحله سایت در حال اجرا است و سرویسها قابل دسترسی هستند.
سپس اپلیکیشن کنسول را باز کنید و روی خط اول کد فایل program.cs یک breakpoint قرار داده و آن را اجرا کنید. ابتدا آدرس سرویس را نگاشت میکنیم و از سرویس درخواست میکنیم که اطلاعات را با فرمت JSON بازگرداند.
سپس توسط متد DeleteAsync که روی آبجکت HttpClient تعریف شده است اکشن متد Cleanup را روی سرویس فراخوانی میکنیم. این فراخوانی تمام دادههای پیشین را حذف میکند.
در قدم بعدی یک مشتری بهمراه دو شماره تماس میسازیم. توجه کنید که برای هر موجودیت مشخصا خاصیت TrackingState را مقدار دهی میکنیم تا کامپوننتهای Change-tracking در EF عملیات لازم SQL برای هر موجودیت را تولید کنند.
سپس توسط متد PostAsync که روی آبجکت HttpClient تعریف شده اکشن متد UpdateCustomer را روی سرویس فراخوانی میکنیم. اگر به این اکشن متد یک breakpoint اضافه کنید خواهید دید که موجودیت مشتری را بعنوان یک پارامتر دریافت میکند و آن را به context جاری اضافه مینماید. با اضافه کردن موجودیت به کانتکست جاری کل object graph اضافه میشود و EF شروع به ردیابی تغییرات آن میکند. دقت کنید که آبجکت موجودیت باید Add شود و نه Attach.
قدم بعدی جالب است، هنگامی که از خاصیت DbChangeTracker استفاده میکنیم. این خاصیت روی آبجکت context تعریف شده و یک <IEnumerable<DbEntityEntry را با نام Entries ارائه میکند. در اینجا بسادگی نوع پایه EntityType را تنظیم میکنیم. این کار به ما اجازه میدهد که در تمام موجودیت هایی که از نوع BaseEntity هستند پیمایش کنیم. اگر بیاد داشته باشید این کلاس، کلاس پایه تمام موجودیتها است. در هر مرحله از پیمایش (iteration) با استفاده از کلاس EntityStateFactory مقدار خاصیت TrackingState را به مقدار متناظر در سیستم ردیابی EF تبدیل میکنیم. اگر کلاینت مقدار این فیلد را به Modified تنظیم کرده باشد پردازش بیشتری انجام میشود. ابتدا وضعیت موجودیت را از Modified به Unchanged تغییر میدهیم. سپس مقادیر اصلی را با فراخوانی متد GetDatabaseValues روی آبجکت Entry از دیتابیس دریافت میکنیم. فراخوانی این متد مقادیر موجود در دیتابیس را برای موجودیت جاری دریافت میکند. سپس مقادیر بدست آمده را به کلکسیون OriginalValues اختصاص میدهیم. پشت پرده، کامپوننتهای EF Change-tracking بصورت خودکار تفاوتهای مقادیر اصلی و مقادیر ارسالی را تشخیص میدهند و فیلدهای مربوطه را با وضعیت Modified علامت گذاری میکنند. فراخوانیهای بعدی متد SaveChanges تنها فیلدهایی که در سمت کلاینت تغییر کرده اند را بروز رسانی خواهد کرد و نه تمام خواص موجودیت را.
در اپلیکیشن کلاینت عملیات افزودن، بروز رسانی و حذف موجودیتها توسط مقداردهی خاصیت TrackingState را نمایش داده ایم.
متد UpdateCustomer در سرویس ما مقادیر TrackingState را به مقادیر متناظر EF تبدیل میکند و آبجکتها را به موتور change-tracking ارسال میکند که نهایتا منجر به تولید دستورات لازم SQL میشود.
نکته: در اپلیکیشنهای واقعی بهتر است کد دسترسی دادهها و مدلهای دامنه را به لایه مجزایی منتقل کنید. همچنین پیاده سازی فعلی change-tracking در سمت کلاینت میتواند توسعه داده شود تا با انواع جنریک کار کند. در این صورت از نوشتن مقادیر زیادی کد تکراری جلوگیری خواهید کرد و از یک پیاده سازی میتوانید برای تمام موجودیتها استفاده کنید.
[Flags] public enum MiniDumpType { MiniDumpNormal = 0x00000000, MiniDumpWithDataSegs = 0x00000001, MiniDumpWithFullMemory = 0x00000002, MiniDumpWithHandleData = 0x00000004, MiniDumpFilterMemory = 0x00000008, MiniDumpScanMemory = 0x00000010, MiniDumpWithUnloadedModules = 0x00000020, MiniDumpWithIndirectlyReferencedMemory = 0x00000040, MiniDumpFilterModulePaths = 0x00000080, MiniDumpWithProcessThreadData = 0x00000100, MiniDumpWithPrivateReadWriteMemory = 0x00000200, MiniDumpWithoutOptionalData = 0x00000400, MiniDumpWithFullMemoryInfo = 0x00000800, MiniDumpWithThreadInfo = 0x00001000, MiniDumpWithCodeSegs = 0x00002000, MiniDumpWithoutManagedState = 0x00004000 }
public static class NativeMethods { [DllImport("Dbghelp.dll")] public static extern bool MiniDumpWriteDump( IntPtr hProcess, int processId, IntPtr hFile, MiniDumpType dumpType, IntPtr exceptionParam, IntPtr userStreamParam, IntPtr callbackParam); }
public static class DebugInfo { public static void CreateMiniDump( string dumpFileName, MiniDumpType dumpType = MiniDumpType.MiniDumpNormal) { using (var stream = File.Create(dumpFileName)) { var process = Process.GetCurrentProcess(); // It is safe to call DangerousGetHandle() here because the process is already crashing. NativeMethods.MiniDumpWriteDump( process.Handle, process.Id, stream.SafeFileHandle.DangerousGetHandle(), dumpType, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero); } } public static void CreateMiniDump(MiniDumpType dumpType = MiniDumpType.MiniDumpNormal) { const string dateFormat = "yyyy-MM-dd-HH-mm-ss-fffZ"; // Example: 2010-09-02-09-50-43-341Z var thisAssembly = Assembly.GetEntryAssembly() ?? Assembly.GetCallingAssembly(); var dumpFileName = string.Format(@"{0}-MiniDump-{1}.dmp", thisAssembly.GetName().Name, DateTime.UtcNow.ToString(dateFormat, CultureInfo.InvariantCulture)); var path = Path.Combine(getApplicationPath(), dumpFileName); CreateMiniDump(path, dumpType); } private static string getApplicationPath() { return HttpContext.Current != null ? HttpRuntime.AppDomainAppPath : Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location); } }
class Program { static void Main(string[] args) { try { var zero = 0; Console.WriteLine(1 / zero); } catch (Exception ex) { Console.Write(ex); DebugInfo.CreateMiniDump(dumpType: MiniDumpType.MiniDumpNormal | MiniDumpType.MiniDumpWithPrivateReadWriteMemory | MiniDumpType.MiniDumpWithDataSegs | MiniDumpType.MiniDumpWithHandleData | MiniDumpType.MiniDumpWithFullMemoryInfo | MiniDumpType.MiniDumpWithThreadInfo | MiniDumpType.MiniDumpWithUnloadedModules); throw; } } }
namespace TestBackend { public class Startup { // ... public void ConfigureServices(IServiceCollection services) { // ... services.AddHttpContextAccessor(); // + services.AddSession() && app.UseSession() services.AddDbContext<TestContext>((serviceProvider, options) => { options.UseSqlServer(GetConnectionString(serviceProvider)); }); // ... } // ... private string GetConnectionString(IServiceProvider serviceProvider) { var connectionStringTemplate = Configuration.GetConnectionString("ConnectionTemplate"); try { var httpContextAccessor = serviceProvider.GetRequiredService<IHttpContextAccessor>(); // This needs services.AddHttpContextAccessor(); var dbName = httpContextAccessor.HttpContext.Session.GetString("databasename"); // This needs services.AddSession(); && app.UseSession(); return connectionStringTemplate.Replace("{db_Name}", dbName); } catch(Exception ex) { var logger = serviceProvider.GetRequiredService<ILoggerFactory>().CreateLogger(nameof(Startup)); logger.LogError("GetConnectionString error", ex, "Failed to get connection string."); } return connectionStringTemplate.Replace("{db_Name}", "---Default-DB-Name-Here---"); } } }
using (var store = new DocumentStore { Url = "http://localhost:8080", DefaultDatabase = "Test2" }.Initialize()) { //... }
Raven.Backup.exe --url==http://localhost:8080 --dest=d:\backup
Raven.Smuggler.exe out http://localhost:8080/ dump.raven
Raven.Smuggler.exe in http://localhost:8080/ dump.raven
dotnet ef dbcontext scaffold "Data Source=(local);Initial Catalog=BloggingCore2016;Integrated Security = true" Microsoft.EntityFrameworkCore.SqlServer -o Entities --context MyDBDataContext --verbose
using System; using System.Collections.Generic; namespace Core1RtmEmptyTest.Entities { public partial class Blog { public Blog() { Post = new HashSet<Post>(); } public int BlogId { get; set; } public string Url { get; set; } public virtual ICollection<Post> Post { get; set; } } }
using System; using System.Collections.Generic; namespace Core1RtmEmptyTest.Entities { public partial class Post { public int PostId { get; set; } public string Content { get; set; } public string Title { get; set; } public virtual Blog Blog { get; set; } public int BlogId { get; set; } } }
using System; using Microsoft.EntityFrameworkCore; using Microsoft.EntityFrameworkCore.Metadata; namespace Core1RtmEmptyTest.Entities { public partial class MyDBDataContext : DbContext { protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) { optionsBuilder.UseSqlServer(@"Data Source=(local);Initial Catalog=BloggingCore2016;Integrated Security = true"); } protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder.Entity<Blog>(entity => { entity.Property(e => e.Url).IsRequired(); }); modelBuilder.Entity<Post>(entity => { entity.HasOne(d => d.Blog) .WithMany(p => p.Post) .HasForeignKey(d => d.BlogId); }); } public virtual DbSet<Blog> Blog { get; set; } public virtual DbSet<Post> Post { get; set; } } }
public virtual Blog Blog { get; set; }
public virtual ICollection<Post> Post { get; set; }
<primary key property name> <navigation property name><primary key property name> <principal entity name><primary key property name>
public virtual Blog Blog { get; set; } public int BlogId { get; set; }
modelBuilder.Entity<Post>(entity => { entity.HasOne(d => d.Blog) .WithMany(p => p.Post) .HasForeignKey(d => d.BlogId); });
dotnet ef dbcontext scaffold "Data Source=(local);Initial Catalog=BloggingCore2016;Integrated Security = true" Microsoft.EntityFrameworkCore.SqlServer -o Entities --context MyDBDataContext --verbose -a
using System; using System.Collections.Generic; using System.ComponentModel.DataAnnotations; using System.ComponentModel.DataAnnotations.Schema; namespace Core1RtmEmptyTest.Entities { public partial class Blog { public Blog() { Post = new HashSet<Post>(); } public int BlogId { get; set; } [Required] public string Url { get; set; } [InverseProperty("Blog")] public virtual ICollection<Post> Post { get; set; } } }
using System; using System.Collections.Generic; using System.ComponentModel.DataAnnotations; using System.ComponentModel.DataAnnotations.Schema; namespace Core1RtmEmptyTest.Entities { public partial class Post { public int PostId { get; set; } public string Content { get; set; } public string Title { get; set; } [ForeignKey("BlogId")] [InverseProperty("Post")] public virtual Blog Blog { get; set; } public int BlogId { get; set; } } }
using System; using Microsoft.EntityFrameworkCore; using Microsoft.EntityFrameworkCore.Metadata; namespace Core1RtmEmptyTest.Entities { public partial class MyDBDataContext : DbContext { protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) { optionsBuilder.UseSqlServer(@"Data Source=(local);Initial Catalog=BloggingCore2016;Integrated Security = true"); } protected override void OnModelCreating(ModelBuilder modelBuilder) { } public virtual DbSet<Blog> Blog { get; set; } public virtual DbSet<Post> Post { get; set; } } }
[ForeignKey("BlogId")] [InverseProperty("Post")] public virtual Blog Blog { get; set; } public int BlogId { get; set; }
[InverseProperty("Blog")] public virtual ICollection<Post> Post { get; set; }
public virtual Blog Blog { get; set; }
var firstPost = context.Post.First(); Console.WriteLine(firstPost.Blog.Url);
System.NullReferenceException Object reference not set to an instance of an object.
var firstPost = context.Post.Include(x => x.Blog).First(); Console.WriteLine(firstPost.Blog.Url);
var blogs = context.Blogs .Include(blog => blog.Posts) .Include(blog => blog.Owner) .ToList();
var blogs = context.Blogs .Include(blog => blog.Posts) .ThenInclude(post => post.Author) .ToList();
var blogs = context.Blogs .Include(blog => blog.Posts) .ThenInclude(post => post.Author) .ThenInclude(author => author.Photo) .ToList();
var blogs = context.Blogs .Include(blog => blog.Posts) .ThenInclude(post => post.Author) .ThenInclude(author => author.Photo) .Include(blog => blog.Owner) .ThenInclude(owner => owner.Photo) .ToList();
var blogs = context.Blogs .Include(blog => blog.Posts) .Select(blog => new { Id = blog.BlogId, Url = blog.Url }) .ToList();
CONSTRAINT [FK_Post_Blog_BlogId] FOREIGN KEY ([BlogId]) REFERENCES [Blog] ([BlogId]) ON DELETE CASCADE
modelBuilder.Entity<Post>() .HasOne(p => p.Blog) .WithMany(b => b.Posts) .OnDelete(DeleteBehavior.Cascade);
modelBuilder.Entity<Post>() .HasOne(p => p.Blog) .WithMany(b => b.Posts) .IsRequired();