[英]How to optimise an Entity framework query with 3 includes
我在.Net 4上使用EF 5
我有以下模型:
public class Order
{
[Key]
public int Id { get; set; }
public string OrderId { get; set; }
public Address BillingAddress { get; set; }
public Address DeliveryAddress { get; set; }
public ICollection<OrderLine> OrderLines { get; set; }
}
public class OrderLine
{
[Key]
public int Id { get; set; }
public string Description { get; set; }
public decimal UnitPrice { get; set; }
public int Quantity { get; set; }
public string SKU { get; set; }
public decimal ShippingCost { get; set; }
public decimal Tax { get; set; }
}
public class Address
{
[Key]
public int Id { get; set; }
public string Addressee { get; set; }
public string AddressLine1 { get; set; }
public string AddressLine2 { get; set; }
public string AddressLine3 { get; set; }
public string Town { get; set; }
public string County { get; set; }
public string Country { get; set; }
public string Postcode { get; set; }
}
和型号配置:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Order>().HasMany(x => x.OrderLines).WithRequired().WillCascadeOnDelete();
modelBuilder.Entity<Order>().HasOptional(x => x.BillingAddress).WithOptionalDependent().WillCascadeOnDelete();
modelBuilder.Entity<Order>().HasOptional(x => x.DeliveryAddress).WithOptionalDependent().WillCascadeOnDelete();
base.OnModelCreating(modelBuilder);
}
当我运行以下查询时,我得到带有19个Join的 sql,对于简单的关系而言似乎过多
context.Orders
.Where(x => x.OrderId == orderId)
.Include(x => x.OrderLines)
.Include(x => x.BillingAddress)
.Include(x => x.DeliveryAddress)
.FirstOrDefault();
难道我做错了什么? 格式化linq查询以优化生成的SQL是否有其他格式?
编辑:
这是实际的查询: https : //gist.github.com/4278014
我认为问题在于帐单和收货地址上的WithOptionalDependent
。 即使将表设置为1:1:1关系,这也会在地址和顺序之间创建1:1关系。
如果将配置更改为使用WithMany
:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Order>().HasMany(x => x.OrderLines).WithRequired().WillCascadeOnDelete();
modelBuilder.Entity<Order>().HasOptional(x => x.BillingAddress).WithMany().WillCascadeOnDelete();
modelBuilder.Entity<Order>().HasOptional(x => x.DeliveryAddress).WithMany().WillCascadeOnDelete();
base.OnModelCreating(modelBuilder);
}
查询要简单得多,基本上等同于:
...
FROM [Orders]
LEFT OUTER JOIN [Addresses] As B ON [Orders].[BillingAddress_Id] = B.[Id]
LEFT OUTER JOIN [Addresses] As D ON [Orders].[DeliveryAddress_Id] = D.[Id]
LEFT OUTER JOIN [OrderLines] ON [Orders].[Id] = [OrderLines].[Order_Id]
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