ASP.NET Core 中的 ORM 之 Dapper

本文轉載自查看原文 2018-08-23 10:11 4409 NET Core/ NET Core Basic

Dapper 簡介
使用 Dapper
使用 Dapper Contrib 或其他擴展
引入工作單元 Unit of Work
源代碼
參考

Dapper 簡介

Dapper是.NET的一款輕量級ORM工具（GitHub），也可稱為簡單對象映射器。在速度方面擁有微型ORM之王的稱號。
它是半自動的，也就是說實體類和SQL語句都要自己寫，但它提供自動對象映射。是通過對IDbConnection接口的擴展來操作數據庫的。

優點：

輕量，只有一個文件
性能高，Dapper的速度接近與IDataReader，取列表的數據超過了DataTable。
支持多種數據庫。Dapper可以在所有Ado.net Providers下工作，包括sqlite, sqlce, firebird, oracle, MySQL, PostgreSQL and SQL Server
使用Dapper可以自動進行對象映射，通過Emit反射IDataReader的序列隊列，來快速的得到和產生對象

使用 Dapper

下面簡單創建一個Web API應用並通過Dapper訪問MySQL數據。

創建MySQL測試數據

CREATE SCHEMA `ormdemo` ;

CREATE TABLE `ormdemo`.`category` (
  `Id` INT NOT NULL AUTO_INCREMENT,
  `name` VARCHAR(45) NOT NULL,
  PRIMARY KEY (`Id`));
  
CREATE TABLE `ormdemo`.`product` (
  `Id` INT NOT NULL AUTO_INCREMENT,
  `Name` VARCHAR(45) NOT NULL,
  `Price` DECIMAL(19,2) NULL,
  `Quantity` INT NULL,
  `CategoryId` INT NOT NULL,
  PRIMARY KEY (`Id`),
  INDEX `fk_product_category_idx` (`CategoryId` ASC),
  CONSTRAINT `fk_product_category`
    FOREIGN KEY (`CategoryId`)
    REFERENCES `ormdemo`.`category` (`Id`)
    ON DELETE CASCADE
    ON UPDATE NO ACTION);  

INSERT INTO `ormdemo`.`category` (`Name`) VALUES("Phones");
INSERT INTO `ormdemo`.`category` (`Name`) VALUES("Computers");

INSERT INTO `ormdemo`.`product` (`Name`,`Price`,`Quantity`,`CategoryId`) VALUES("iPhone8",4999.99,10,1);
INSERT INTO `ormdemo`.`product` (`Name`,`Price`,`Quantity`,`CategoryId`) VALUES("iPhone7",2999.99,10,1);
INSERT INTO `ormdemo`.`product` (`Name`,`Price`,`Quantity`,`CategoryId`) VALUES("HP750",6000.00,5,2);
INSERT INTO `ormdemo`.`product` (`Name`,`Price`,`Quantity`,`CategoryId`) VALUES("HP5000",12000.00,10,2);

創建Web API應用並添加NuGet引用

Install-Package MySql.Data
Install-Package Dapper

新建一個Product類

public class Category
{
    public int Id { get; set; }

    public string Name { get; set; }
}

public class Product
{
    public int Id { get; set; }

    public string Name { get; set; }

    public int Quantity { get; set; }

    public decimal Price { get; set; }

    public int CategoryId { get; set; }

    public virtual Category Category { get; set; }
}

新建一個DBConfig類用於創建並返回數據庫連接

using MySql.Data.MySqlClient;
using System.Data;
using System.Configuration;

public class DBConfig
{
    //ConfigurationManager.ConnectionStrings["Connection"].ConnectionString;
    private static string DefaultSqlConnectionString = @"server=127.0.0.1;database=ormdemo;uid=root;pwd=Open0001;SslMode=none;";

    public static IDbConnection GetSqlConnection(string sqlConnectionString = null)
    {
        if (string.IsNullOrWhiteSpace(sqlConnectionString))
        {
            sqlConnectionString = DefaultSqlConnectionString;
        }
        IDbConnection conn = new MySqlConnection(sqlConnectionString);
        conn.Open();
        return conn;
    }
}

創建簡單的倉儲接口和類

public interface IProductRepository
{
    Task<bool> AddAsync(Product prod);
    Task<IEnumerable<Product>> GetAllAsync();
    Task<Product> GetByIDAsync(int id);
    Task<bool> DeleteAsync(int id);
    Task<bool> UpdateAsync(Product prod);
}

public class ProductRepository : IProductRepository
{
    public async Task<IEnumerable<Product>> GetAllAsync()
    {
        using (IDbConnection conn = DBConfig.GetSqlConnection())
        {
            return await conn.QueryAsync<Product>(@"SELECT Id
                                            ,Name
                                            ,Quantity
                                            ,Price
                                            ,CategoryId
                                        FROM Product");
        }
    }

    public async Task<Product> GetByIDAsync(int id)
    {
        using (IDbConnection conn = DBConfig.GetSqlConnection())
        {
            string sql = @"SELECT Id
                                ,Name
                                ,Quantity
                                ,Price 
                                ,CategoryId
                            FROM Product
                            WHERE Id = @Id";
            return await conn.QueryFirstOrDefaultAsync<Product>(sql, new { Id = id });
        }
    }

    public async Task<bool> AddAsync(Product prod)
    {
        using (IDbConnection conn = DBConfig.GetSqlConnection())
        {
            string sql = @"INSERT INTO Product 
                            (Name
                            ,Quantity
                            ,Price
                            ,CategoryId)
                        VALUES
                            (@Name
                            ,@Quantity
                            ,@Price
                            ,@CategoryId)";
            return await conn.ExecuteAsync(sql, prod) > 0;
        }
    }

    public async Task<bool> UpdateAsync(Product prod)
    {
        using (IDbConnection conn = DBConfig.GetSqlConnection())
        {
            string sql = @"UPDATE Product SET 
                                Name = @Name
                                ,Quantity = @Quantity
                                ,Price= @Price
                                ,CategoryId= @CategoryId
                           WHERE Id = @Id";
            return await conn.ExecuteAsync(sql, prod) > 0;
        }
    }

    public async Task<bool> DeleteAsync(int id)
    {
        using (IDbConnection conn = DBConfig.GetSqlConnection())
        {
            string sql = @"DELETE FROM Product
                            WHERE Id = @Id";
            return await conn.ExecuteAsync(sql, new { Id = id }) > 0;
        }
    }
}

在Startup ConfigureServices方法里面配置依賴注入

public void ConfigureServices(IServiceCollection services)
{
    services.AddTransient<IProductRepository, ProductRepository>();

    services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
}

在Controller里面調用倉儲方法

[Route("api/[controller]")]
[ApiController]
public class ProductController : ControllerBase
{
    private readonly IProductRepository _productRepository;
    public ProductController(IProductRepository productRepository)
    {
        _productRepository = productRepository;
    }

    [HttpGet]
    public async Task<IActionResult> Get()
    {
        var data = await _productRepository.GetAllAsync();
        return Ok(data);
    }

    [HttpGet("{id}")]
    public async Task<IActionResult> Get(int id)
    {
        var data = await _productRepository.GetByIDAsync(id);
        return Ok(data);
    }

    [HttpPost]
    public async Task<IActionResult> Post([FromBody] Product prod)
    {
        if (!ModelState.IsValid)
        {
            return BadRequest(ModelState);
        }

        await _productRepository.AddAsync(prod);
        return NoContent();
    }

    [HttpPut("{id}")]
    public async Task<IActionResult> Put(int id, [FromBody] Product prod)
    {
        if (!ModelState.IsValid)
        {
            return BadRequest(ModelState);
        }

        var model = await _productRepository.GetByIDAsync(id);
        model.Name = prod.Name;
        model.Quantity = prod.Quantity;
        model.Price = prod.Price;
        await _productRepository.UpdateAsync(model);

        return NoContent();
    }

    [HttpDelete("{id}")]
    public async Task<IActionResult> Delete(int id)
    {
        await _productRepository.DeleteAsync(id);
        return NoContent();
    }
}

測試API是否可以正常工作

Dapper對存儲過程和事務的支持

存儲過程

using (var connection = My.ConnectionFactory())
{
	connection.Open();

	var affectedRows = connection.Execute(sql,
		new {Kind = InvoiceKind.WebInvoice, Code = "Single_Insert_1"},
		commandType: CommandType.StoredProcedure);

	My.Result.Show(affectedRows);
}

事務

using (var connection = My.ConnectionFactory())
{
	connection.Open();
	
	using (var transaction = connection.BeginTransaction())
	{
		var affectedRows = connection.Execute(sql, new {CustomerName = "Mark"}, transaction: transaction);
		
		transaction.Commit();
	}
}

Dapper對多表映射的支持

var selectAllProductWithCategorySQL = @"select * from product p 
    inner join category c on c.Id = p.CategoryId
    Order by p.Id";
var allProductWithCategory = connection.Query<Product, Category, Product>(selectAllProductWithCategorySQL, (prod, cg) => { prod.Category = cg; return prod; });

使用 Dapper Contrib 或其他擴展

Dapper Contrib擴展Dapper提供了CRUD的方法

Get
GetAll
Insert
Update
Delete
DeleteAll

添加NuGet引用Dapper.Contrib
```
Install-Package Dapper.Contrib
```

為Product類添加數據注解

[Table("Product")]
public class Product
{
    [Key]
    public int Id { get; set; }

    public string Name { get; set; }

    public int Quantity { get; set; }

    public decimal Price { get; set; }

    public int CategoryId { get; set; }

    public virtual Category Category { get; set; }
}

增加一個新的倉儲類繼承

public class ContribProductRepository : IProductRepository
{
    public async Task<bool> AddAsync(Product prod)
    {
        using (IDbConnection conn = DBConfig.GetSqlConnection())
        {
            return await conn.InsertAsync(prod) > 0;
        }
    }

    public async Task<IEnumerable<Product>> GetAllAsync()
    {
        using (IDbConnection conn = DBConfig.GetSqlConnection())
        {
            return await conn.GetAllAsync<Product>();
        }
    }

    public async Task<Product> GetByIDAsync(int id)
    {
        using (IDbConnection conn = DBConfig.GetSqlConnection())
        {
            return await conn.GetAsync<Product>(id);
        }
    }

    public async Task<bool> DeleteAsync(int id)
    {
        using (IDbConnection conn = DBConfig.GetSqlConnection())
        {
            var entity = await conn.GetAsync<Product>(id);
            return await conn.DeleteAsync(entity);
        }
    }

    public async Task<bool> UpdateAsync(Product prod)
    {
        using (IDbConnection conn = DBConfig.GetSqlConnection())
        {
            return await conn.UpdateAsync(prod);
        }
    }
}

修改Startup ConfigureServices方法里面配置依賴注入

services.AddTransient<IProductRepository, ContribProductRepository>();

測試，這樣可以少寫了不少基本的SQL語句。

其他一些開源的Dapper擴展

類庫	提供的方法
Dapper.SimpleCRUD	`Get` `GetList` `GetListPaged` `Insert` `Update` `Delete` `DeleteList` `RecordCount`
Dapper Plus	`Bulk Insert` `Bulk Delete` `Bulk Update` `Bulk Merge` `Bulk Action Async` `Bulk Also Action` `Bulk Then Action`
Dapper.FastCRUD	`Get` `Find` `Insert` `Update` `BulkUpdate` `Delete` `BulkDelete` `Count`
Dapper.Mapper	`Multi-mapping`

引入工作單元 Unit of Work

倉儲模式往往需要工作單元模式的介入來負責一系列倉儲對象的持久化，確保數據完整性。網上關於工作單元模式的實現方式有多種，但其本質都是工作單元類通過創建一個所有倉儲共享的數據庫上下文對象，來組織多個倉儲對象。

網上的一些實現方式：

Implementing the Repository and Unit of Work Patterns in an ASP.NET MVC Application
微軟之前給出的一個示例，倉儲類做為工作單元的變量，並通過工作單元傳入一致的context參數創建。

public class UnitOfWork : IDisposable
{
    private SchoolContext context = new SchoolContext();
    private GenericRepository<Department> departmentRepository;
    private GenericRepository<Course> courseRepository;

    public GenericRepository<Department> DepartmentRepository
    {
        get
        {

            if (this.departmentRepository == null)
            {
                this.departmentRepository = new GenericRepository<Department>(context);
            }
            return departmentRepository;
        }
    }

    public GenericRepository<Course> CourseRepository
    {
        get
        {

            if (this.courseRepository == null)
            {
                this.courseRepository = new GenericRepository<Course>(context);
            }
            return courseRepository;
        }
    }

    public void Save()
    {
        context.SaveChanges();
    }

    private bool disposed = false;

    protected virtual void Dispose(bool disposing)
    {
        if (!this.disposed)
        {
            if (disposing)
            {
                context.Dispose();
            }
        }
        this.disposed = true;
    }

    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }
}

DDD 領域驅動設計－談談 Repository、IUnitOfWork 和 IDbContext 的實踐
博客園一位大神的總結，最終采用的方案是倉儲類負責查詢，工作單元類負責增刪改等數據持久化操作。

優缺點不作討論，適合自己的就是最好的，這里采用了另外一種實現方式：

定義DapperDBContext

public interface IContext : IDisposable
{
    bool IsTransactionStarted { get; }

    void BeginTransaction();

    void Commit();

    void Rollback();
}

public abstract class DapperDBContext : IContext
{
    private IDbConnection _connection;
    private IDbTransaction _transaction;
    private int? _commandTimeout = null;
    private readonly DapperDBContextOptions _options;

    public bool IsTransactionStarted { get; private set; }

    protected abstract IDbConnection CreateConnection(string connectionString);

    protected DapperDBContext(IOptions<DapperDBContextOptions> optionsAccessor)
    {
        _options = optionsAccessor.Value;

        _connection = CreateConnection(_options.Configuration);
        _connection.Open();

        DebugPrint("Connection started.");
    }

    #region Transaction

    public void BeginTransaction()
    {
        if (IsTransactionStarted)
            throw new InvalidOperationException("Transaction is already started.");

        _transaction = _connection.BeginTransaction();
        IsTransactionStarted = true;

        DebugPrint("Transaction started.");
    }

    public void Commit()
    {
        if (!IsTransactionStarted)
            throw new InvalidOperationException("No transaction started.");

        _transaction.Commit();
        _transaction = null;

        IsTransactionStarted = false;

        DebugPrint("Transaction committed.");
    }

    public void Rollback()
    {
        if (!IsTransactionStarted)
            throw new InvalidOperationException("No transaction started.");

        _transaction.Rollback();
        _transaction.Dispose();
        _transaction = null;

        IsTransactionStarted = false;

        DebugPrint("Transaction rollbacked and disposed.");
    }

    #endregion Transaction

    #region Dapper Execute & Query

    public async Task<int> ExecuteAsync(string sql, object param = null, CommandType commandType = CommandType.Text)
    {
        return await _connection.ExecuteAsync(sql, param, _transaction, _commandTimeout, commandType);
    }

    public async Task<IEnumerable<T>> QueryAsync<T>(string sql, object param = null, CommandType commandType = CommandType.Text)
    {
        return await _connection.QueryAsync<T>(sql, param, _transaction, _commandTimeout, commandType);
    }

    public async Task<T> QueryFirstOrDefaultAsync<T>(string sql, object param = null, CommandType commandType = CommandType.Text)
    {
        return await _connection.QueryFirstOrDefaultAsync<T>(sql, param, _transaction, _commandTimeout, commandType);
    }

    public async Task<IEnumerable<TReturn>> QueryAsync<TFirst, TSecond, TReturn>(string sql, Func<TFirst, TSecond, TReturn> map, object param = null, string splitOn = "Id", CommandType commandType = CommandType.Text)
    {
        return await _connection.QueryAsync(sql, map, param, _transaction, true, splitOn, _commandTimeout, commandType);
    }

    #endregion Dapper Execute & Query

    public void Dispose()
    {
        if (IsTransactionStarted)
            Rollback();

        _connection.Close();
        _connection.Dispose();
        _connection = null;

        DebugPrint("Connection closed and disposed.");
    }

    private void DebugPrint(string message)
    {
#if DEBUG
        Debug.Print(">>> UnitOfWorkWithDapper - Thread {0}: {1}", Thread.CurrentThread.ManagedThreadId, message);
#endif
    }
}

定義UnitOfWork

public interface IUnitOfWork : IDisposable
{
    void SaveChanges();
}

public class UnitOfWork : IUnitOfWork
{
    private readonly IContext _context;

    public UnitOfWork(IContext context)
    {
        _context = context;
        _context.BeginTransaction();
    }

    public void SaveChanges()
    {
        if (!_context.IsTransactionStarted)
            throw new InvalidOperationException("Transaction have already been commited or disposed.");

        _context.Commit();
    }

    public void Dispose()
    {
        if (_context.IsTransactionStarted)
            _context.Rollback();
    }
}

定義UnitOfWorkFactory

public interface IUnitOfWorkFactory
{
    IUnitOfWork Create();
}

public class DapperUnitOfWorkFactory : IUnitOfWorkFactory
{
    private readonly DapperDBContext _context;

    public DapperUnitOfWorkFactory(DapperDBContext context)
    {
        _context = context;
    }

    public IUnitOfWork Create()
    {
        return new UnitOfWork(_context);
    }
}

定義服務擴展

public class DapperDBContextOptions : IOptions<DapperDBContextOptions>
{
    public string Configuration { get; set; }

    DapperDBContextOptions IOptions<DapperDBContextOptions>.Value
    {
        get { return this; }
    }
}

public static class DapperDBContextServiceCollectionExtensions
{
    public static IServiceCollection AddDapperDBContext<T>(this IServiceCollection services, Action<DapperDBContextOptions> setupAction) where T : DapperDBContext
    {
        if (services == null)
        {
            throw new ArgumentNullException(nameof(services));
        }

        if (setupAction == null)
        {
            throw new ArgumentNullException(nameof(setupAction));
        }

        services.AddOptions();
        services.Configure(setupAction);
        services.AddScoped<DapperDBContext, T>();
        services.AddScoped<IUnitOfWorkFactory, DapperUnitOfWorkFactory>();

        return services;
    }
}

怎么使用

創建一個自己的Context並繼承DapperDBContext。下面測試的TestDBContext是采用MySQL數據庫並返回MySqlConnection。

public class TestDBContext : DapperDBContext
{
    public TestDBContext(IOptions<DapperDBContextOptions> optionsAccessor) : base(optionsAccessor)
    {
    }

    protected override IDbConnection CreateConnection(string connectionString)
    {
        IDbConnection conn = new MySqlConnection(connectionString);
        return conn;
    }
}

倉儲類里面添加DapperDBContext引用

public class UowProductRepository : IProductRepository
{
    private readonly DapperDBContext _context;
    public UowProductRepository(DapperDBContext context)
    {
        _context = context;
    }


    public async Task<Product> GetByIDAsync(int id)
    {
        string sql = @"SELECT Id
                            ,Name
                            ,Quantity
                            ,Price 
                            ,CategoryId
                        FROM Product
                        WHERE Id = @Id";
        return await _context.QueryFirstOrDefaultAsync<Product>(sql, new { Id = id });
    }

    public async Task<bool> AddAsync(Product prod)
    {
        string sql = @"INSERT INTO Product 
                        (Name
                        ,Quantity
                        ,Price
                        ,CategoryId)
                    VALUES
                        (@Name
                        ,@Quantity
                        ,@Price
                        ,@CategoryId)";
        return await _context.ExecuteAsync(sql, prod) > 0;
    }
}

Startup里面注冊服務

public void ConfigureServices(IServiceCollection services)
{
    services.AddDapperDBContext<TestDBContext>(options => {
        options.Configuration = @"server=127.0.0.1;database=ormdemo;uid=root;pwd=password;SslMode=none;";
    });

    services.AddTransient<IProductRepository, UowProductRepository>();
    services.AddTransient<ICategoryRepository, UowCategoryRepository>();

    services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
}

Controller調用

public class ProductController : ControllerBase
{
    private readonly IUnitOfWorkFactory _uowFactory;
    private readonly IProductRepository _productRepository;
    private readonly ICategoryRepository _categoryRepository;
    
    public ProductController(IUnitOfWorkFactory uowFactory, IProductRepository productRepository, ICategoryRepository categoryRepository)
    {
        _uowFactory = uowFactory;
        _productRepository = productRepository;
        _categoryRepository = categoryRepository;
    }

    [HttpGet("{id}")]
    public async Task<IActionResult> Get(int id)
    {
        var data = await _productRepository.GetByIDAsync(id);
        return Ok(data);
    }

    [HttpPost]
    public async Task<IActionResult> Post([FromBody] Product prod)
    {
        if (!ModelState.IsValid)
        {
            return BadRequest(ModelState);
        }

        //await _productRepository.AddAsync(prod);

        using (var uow = _uowFactory.Create())
        {
            await _productRepository.AddAsync(prod);

            uow.SaveChanges();
        }

        return NoContent();
    }
}

源代碼

Github

參考

免責聲明！

本站轉載的文章為個人學習借鑒使用，本站對版權不負任何法律責任。如果侵犯了您的隱私權益，請聯系本站郵箱yoyou2525@163.com刪除。

猜您在找 Use Dapper ORM With ASP.NET Core Asp.net Core 系列之--2.ORM初探:Dapper實現MySql數據庫各類操作 asp.net core系列 66 Dapper介紹--Micro-ORM asp.net core 使用Mysql和Dapper ASP .Net Core 使用 Dapper 輕型ORM框架 ASP.NET Core 實戰：基於 Dapper 擴展你的數據訪問方法 Asp.Net Core + Dapper + Repository 模式 + TDD 學習筆記 .net core 3.1 加入ORM框架（Dapper） .net core 3.1 加入ORM框架（Dapper）淺談ASP.NET Core中的DI