Question

我们有Customer事务表，其中包含多个带外键的查找表。我们希望看到3桌连在一起。如果存储库一起连接表，还是仅用于读取单个表？

如果是这样，示例存储库将数据放入什么？我听说它无法了解Viewmodels等，那么结果会进入哪种对象数据类型？

存储库：

void GetByCustomerTransactionId()
{
   var result = from ct in CustomerTransaction
    join pt in ProductType on pt.ProductTypeId equals ct.ProductTypeId 
    join ss in Status on s.StatusId equals ct.StatusId 
    select new all fields
}

模特：

public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
}

public class ProductType
{
    public int ProductTypeId{ get; set; }
    public string ProductName { get; set; },
    public string ProductDescription { get; set; },
}

public class StatusType
{
    public int StatusId{ get; set; }
    public string StatusName{ get; set; },
    public string Description{ get; set; },

}

Answer 1

考虑到表上存在外键约束，您只需执行此操作而无需自己进行任何连接

public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
    // Add this
    public ProductType ProductType { get; set;}
    public StatusType StatusType { get; set;} 
}

然后在您的存储库上只需获取CustomerTransation，它也将根据其外键返回已连接的表

CustomerTransaction GetByCustomerTransactionId(int id)
{
   var result = ct.CustomerTransaction.Where(x => x.CustomerTransactionId == id).ToList()
  return result;
}

这将为您提供CustomerTransactions，其StatusType和ProductType

Answer 2

在ASP.NET Core中建立一对多关系的方法之一是Fluent API

public class CustomerTransaction
{
    public int CustomerTransactionId { get; set; }
    public string DateOfPurchase{ get; set; }
    public int PurchaseAmount { get; set; }

    // relationships
    public ProductType ProductType { get; set; }
    public int ProductTypeId { get; set; } 

    public StatusType StatusType { get; set; }
    public int StatusID { get; set; }  
}

public class ProductType
{
    public int ProductTypeId { get; set; }
    public string ProductName { get; set; }
    public string ProductDescription { get; set; }

    // relationships
    public ICollection<CustomerTransaction> CustomerTransactions { get; set; }
}

public class StatusType
{
    public int StatusId { get; set; }
    public string StatusName { get; set; }
    public string Description { get; set; }

    // relationships
    public ICollection<CustomerTransaction> CustomerTransactions { get; set; }
}

然后只需使用Include在结果中将它们正确地连接在一起。

public void GetByCustomerTransactionId(int id)
{
     var result = context.CustomerTransaction.Where(x=>x.CustomerTransactionId == id)
     .Include(i=>i.ProductType)
     .Include(i=>i.StatusType);
}

用于连接表的MVC核心存储库

2 个答案: