ABP introductory series (4) - Domain layer definition and implementation of warehousing

Repository: Repository is used to operate the database for data access. The warehousing interface is defined at the domain layer, while the warehousing implementation class should be written at the infrastructure layer.

In ABP, the warehousing class must implement the IRepository interface, which defines commonly used addition, deletion, modification, and aggregation methods, including synchronous and asynchronous methods. It mainly includes the following methods:

ABP provides a default implementation of this interface for different ORM frameworks;
For EntityFramework, Provides an implementation of the generic version of EfRepositoryBase.
For NHibernate, the implementation of the generic version of NhRepositoryBase is provided.

The implementation of the generic version means that most of the time, these methods are sufficient to meet the needs of general entities. If these methods are sufficient for the entity, we don't need to create the repository interface/class required by this entity.

You can directly define the warehouse reference in the application service layer and then inject it through the constructor. Task warehousing can be used in our application service layer in the following way:

public class TaskAppService : ITaskAppService { 
private readonly IRepository<Task> _taskRepository; 
public TaskAppService(IRepository<Task> taskRepository) 
{ 
    _taskRepository = taskRepository; 
}

This is the method used in the sample code

2. How to implement custom warehousing

Suppose we need to find out which tasks a user has been assigned.

In the domain layer, create the IRepositories folder, and then define IBackendTaskRepository.

namespace LearningMpaAbp.IRepositories
{/// <summary>/// 自定义仓储示例/// </summary>public interface IBackendTaskRepository : IRepository<Task>
{    /// <summary>
    /// 获取某个用户分配了哪些任务
    /// </summary>
    /// <param name="personId">用户Id</param>
    /// <returns>任务列表</returns>
    List<Task> GetTaskByAssignedPersonId(long personId);
}
}

In the infrastructure layer, the warehousing is implemented.

namespace LearningMpaAbp.EntityFramework.Repositories
{public class BackendTaskRepository:LearningMpaAbpRepositoryBase<Task>,IBackendTaskRepository{   
public BackendTaskRepository(IDbContextProvider<LearningMpaAbpDbContext> dbContextProvider) : base(dbContextProvider)
    {
    }    /// <summary>
    /// 获取某个用户分配了哪些任务
    /// </summary>
    /// <param name="personId">用户Id</param>
    /// <returns>任务列表</returns>
    public List<Task> GetTaskByAssignedPersonId(long personId)
    {        var query = GetAll();        if (personId>0)
        {
            query = query.Where(t => t.AssignedPersonId == personId);
        }        return query.ToList();
    }
}
}

This warehouse implementation inherits from the LearningMpaAbpRepositoryBase generic abstract class generated by the template, and then implements the IBackendTaskRepository interface. Here you need to explicitly declare the parameterized constructor of the implementation class, and use the generic IDbContextProvider to pass the database context subclass ChargeStationContext to the constructor of the parent class.

3. Warehousing precautions

In the warehousing method, ABP automatically opens and closes the database connection.

When the warehousing method is called, the database connection is automatically opened and the transaction is started.

When a repository method calls another repository method, they actually share the same database connection and transaction.

Repository objects are temporary because the IRepository interface inherits from the ITransientDependency interface by default. Therefore, the IOC container will automatically create a new instance of the warehousing object only when it needs to be injected.

The default generic repository can meet most of our needs. Only if this is not satisfied will a customized repository be created.

The source code has been uploaded to Github-LearningMpaAbp, you can refer to it yourself.
ABP introductory series directory - practical exercises for learning the Abp framework

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