repository-pattern - 如何使用 Dapper 实现工作单元模式？

Question

目前，我正在尝试将 Dapper ORM 与工作单元 + 存储库模式一起使用。

我想使用工作单元而不是简单的小巧存储库，因为我的插入和更新需要一定程度的事务处理。我找不到任何有用的示例，因为大多数示例似乎使用 Entity Framework 并且在工作单元中存在泄漏问题。

有人可以指出我正确的方向吗？

Answer 1

对此无需手动解决方案。使用框架中已有的类可以非常简单地实现您想要的。

/// <summary>
/// Register a single instance using whatever DI system you like.
/// </summary>
class ConnectionFactory
{
    private string _connectionString;

    public ConnectionFactory(string connectionString)
    {
        _connectionString = connectionString;
    }

    public IDbConnection CreateConnection()
    {
        return new SqlConnection(_connectionString);
    }
}


/// <summary>
/// Generally, in a properly normalized database, your repos wouldn't map to a single table,
/// but be an aggregate of data from several tables.
/// </summary>
class ProductRepo
{
    private ConnectionFactory _connectionFactory;

    public ProductRepo(ConnectionFactory connectionFactory)
    {
        _connectionFactory = connectionFactory;
    }

    public Product Get(int id)
    {
        // Allow connection pooling to worry about connection lifetime, that's its job.
        using (var con = _connectionFactory.CreateConnection())
        {
            return con.Get<Product>(id);
        }
    }

    // ...
}

class OrderRepo
{
    // As above.
    // ...
}

class ProductController : ControllerBase
{
    private ProductRepo _productRepo;
    private OrderRepo _orderRepo;

    public ProductController(ProductRepo productRepo, OrderRepo orderRepo)
    {
        _productRepo = productRepo;
        _orderRepo = orderRepo;
    }

    [HttpGet]
    public Task<IAsyncResult> Get(int id)
    {
        // This establishes your transaction.
        // Default isolation level is 'serializable' which is generally desirable and is configurable.
        // Enable async flow option in case subordinate async code results in a thread continuation switch.
        // If you don't need this transaction here, don't use it, or put it where it is needed.
        using (var trn = new TransactionScope(TransactionScopeAsyncFlowOption.Enabled))
        {
            Product product = _productRepo.Get(id);

            // Use additional repositories and do something that actually requires an explicit transaction.
            // A single SQL statement does not require a transaction on SQL Server due to default autocommit mode.
            // ...

            return Ok(product);
        }
    }
}