根据另一个表中的自定义属性过滤值

Question

我有两个表 DefaultAttributes 和 CustomAttributes。

DefaultAttributeTable: 
1. Id
2. Product
4. Description

CustomAtrributeTable:
1. Id
2. DefaultAttributeMappingId(FK from DefaultAttributeTable)
3. CustomAtrributeName
4. CustomeAttributeValue

用户输入的条目：

1. 用户更新值产品 -> 蔬菜、描述 -> 家居用品、IsOrganic（已创建自定义属性）-> True 和 IsDisposable（已创建自定义属性）-> True

2. 用户更新值 Product -> Fruits, Description -> House Hold Item, IsOrganic(Custom Attribute created) -> True and IsDisposable(Custom Attribute created) -> True

3. 用户更新值 Product -> Plastic, Description -> House Hold Item, IsOrganic(Custom Attribute created) -> False and IsDisposable(Custom Attribute created) -> False

那么表格中的值就会更新

默认属性表：

自定义属性表：

我想组合这两个表并选择 Id、product、IsOrganic、IsDisposable 并根据 isorganic 列过滤值。此外，自定义属性列名称应取自 CustomAtrributeTable。请向我建议如何在 SQL 和 Linq Query 中实现它。过滤后的值应该是

Answer 1

你可以在 SQL 中试试这个

select DA.Id, DA.Product, CA.CustomeAttributeValue as IsOrganic  
from DeafaultAtrributeTable as DA inner join CustomAttributeTable as CA
on DA.Id = CA.DefaultAttributeMappingId

在 LINQ 中

var query =
   from DA in DeafaultAtrributeTable 
   join CA in CustomAttributeTable  on DA.ID equals CA.DefaultAttributeMappingId
   where CA.CustomeAttributeValue == true
   select new { Id = DA.Id, Product = DA.Product, IsOrganic = CA.CustomeAttributeValue };

或LINQ扩展方法是

  var query = DeafaultAtrributeTable     // your starting point - table in the "from" statement
      .Join(CustomAttributeTable  , // the source table of the inner join
         DA => DA.ID,        // Select the primary key (the first part of the "on" clause in an sql "join" statement)
         CA => CA.DefaultAttributeMappingId,   // Select the foreign key (the second part of the "on" clause)
        (DA, CA) => new { Id = DA.Id, Product = DA.Product, IsOrganic = 
     CA.CustomeAttributeValue }) // selection 
    .Where(RES => RES.CA.CustomeAttributeValue == true);    // where statement

Answer 2

试试这个

public class Filtered
{
    public int ProductId { get; set; }
    public string ProductName { get; set; }
    public bool? IsOrganic { get; set; }
    public bool? IsDisposable { get; set; }
}

var result = defaultAttributeTable.Join(customAtrributeTable, DAT => DAT.Id, CAT => CAT.DefaultAttributeTableId, (DAT, CAT) => 
            new Filtered 
            {
//your join with null values for opposing isdisposable and isorganic
                ProductId = DAT.Id,
                IsDisposable = CAT.CustomAtrributeName == "IsDisposable" ? (bool?)CAT.CustomeAttributeValue : null,
                IsOrganic = CAT.CustomAtrributeName == "IsOrganic" ? (bool?)CAT.CustomeAttributeValue : null,
                ProductName = DAT.Product
            }).GroupBy(q => q.ProductId) //group it by productid
              .Select(q =>
                   new Filtered
                   {
//this will flatten opposing isorganic and isdisposable
                       ProductId = q.Key,
                       IsDisposable = q.First(e => e.IsDisposable.HasValue).IsDisposable.Value,
                       IsOrganic = q.First(e => e.IsOrganic.HasValue).IsOrganic.Value,
                       ProductName = q.First(e => e.ProductId == q.Key).ProductName
                   }).ToList();