我对EF很新,我有一点问题。
我只想删除数据库中的项目。我正在使用SQL Server 2012 Express,VS2012,AdventureWorks 2012。
我执行的查询如下:
context = new AWEntities();
var removedItem = context.Addresses
.Include("StateProvince")
.Include("SalesOrderHeaders")
.Include("BusinessEntityAddresses").Single(d => d.AddressID == 11);
context.Addresses.Remove(removedItem);
context.SaveChanges();
我得到的错误是
DELETE语句与REFERENCE约束“FK_SalesOrderHeader_Address_ShipToAddressID”冲突。冲突发生在数据库“AdventureWorks2012”,表“Sales.SalesOrderHeader”,列“ShipToAddressID”中。该语句已终止。
这实际上是删除项目和其他表中相应条目的好方法吗?
请指出我正确的方向。
public partial class Address
{
public Address()
{
this.BusinessEntityAddresses = new HashSet<BusinessEntityAddress>();
this.SalesOrderHeaders = new HashSet<SalesOrderHeader>();
}
public int AddressID { get; set; }
public string AddressLine1 { get; set; }
public string AddressLine2 { get; set; }
public string City { get; set; }
public int StateProvinceID { get; set; }
public string PostalCode { get; set; }
public System.Data.Spatial.DbGeography SpatialLocation { get; set; }
public System.Guid rowguid { get; set; }
public System.DateTime ModifiedDate { get; set; }
public virtual StateProvince StateProvince { get; set; }
public virtual ICollection<BusinessEntityAddress> BusinessEntityAddresses { get; set; }
public virtual ICollection<SalesOrderHeader> SalesOrderHeaders { get; set; }
}
public partial class StateProvince
{
public StateProvince()
{
this.Addresses = new HashSet<Address>();
this.SalesTaxRates = new HashSet<SalesTaxRate>();
}
public int StateProvinceID { get; set; }
public string StateProvinceCode { get; set; }
public string CountryRegionCode { get; set; }
public bool IsOnlyStateProvinceFlag { get; set; }
public string Name { get; set; }
public int TerritoryID { get; set; }
public System.Guid rowguid { get; set; }
public System.DateTime ModifiedDate { get; set; }
public virtual ICollection<Address> Addresses { get; set; }
public virtual CountryRegion CountryRegion { get; set; }
public virtual ICollection<SalesTaxRate> SalesTaxRates { get; set; }
public virtual SalesTerritory SalesTerritory { get; set; }
}
}
public partial class BusinessEntityAddress
{
public int BusinessEntityID { get; set; }
public int AddressID { get; set; }
public int AddressTypeID { get; set; }
public System.Guid rowguid { get; set; }
public System.DateTime ModifiedDate { get; set; }
public virtual Address Address { get; set; }
public virtual AddressType AddressType { get; set; }
public virtual BusinessEntity BusinessEntity { get; set; }
}
public partial class SalesOrderHeader
{
public SalesOrderHeader()
{
this.SalesOrderDetails = new HashSet<SalesOrderDetail>();
this.SalesOrderHeaderSalesReasons = new HashSet<SalesOrderHeaderSalesReason>();
}
public int SalesOrderID { get; set; }
public byte RevisionNumber { get; set; }
public System.DateTime OrderDate { get; set; }
public System.DateTime DueDate { get; set; }
public Nullable<System.DateTime> ShipDate { get; set; }
public byte Status { get; set; }
public bool OnlineOrderFlag { get; set; }
public string SalesOrderNumber { get; set; }
public string PurchaseOrderNumber { get; set; }
public string AccountNumber { get; set; }
public int CustomerID { get; set; }
public Nullable<int> SalesPersonID { get; set; }
public Nullable<int> TerritoryID { get; set; }
public int BillToAddressID { get; set; }
public int ShipToAddressID { get; set; }
public int ShipMethodID { get; set; }
public Nullable<int> CreditCardID { get; set; }
public string CreditCardApprovalCode { get; set; }
public Nullable<int> CurrencyRateID { get; set; }
public decimal SubTotal { get; set; }
public decimal TaxAmt { get; set; }
public decimal Freight { get; set; }
public decimal TotalDue { get; set; }
public string Comment { get; set; }
public System.Guid rowguid { get; set; }
public System.DateTime ModifiedDate { get; set; }
public virtual Address Address { get; set; }
public virtual ShipMethod ShipMethod { get; set; }
public virtual CreditCard CreditCard { get; set; }
public virtual CurrencyRate CurrencyRate { get; set; }
public virtual Customer Customer { get; set; }
public virtual ICollection<SalesOrderDetail> SalesOrderDetails { get; set; }
public virtual SalesPerson SalesPerson { get; set; }
public virtual SalesTerritory SalesTerritory { get; set; }
public virtual ICollection<SalesOrderHeaderSalesReason> SalesOrderHeaderSalesReasons { get; set; }
}
无法从你所说的内容中说出多少,但是你可以从使用DbModelBuilder解决级联问题中受益:
modelBuilder.Entity<Parent>()
.HasMany<Child>(c => c.Children)
.WithOptional(x => x.Parent)
.WillCascadeOnDelete(true);
同样,需要有关模型结构的更多信息,以确定这是否是正确的方法。
无论是在您的删除方法中,还是首先删除所有子项,然后删除父项。
modelBuilder.Entity<Parent>()
.HasMany<Child>(c => c.Children)
.WithOptional(x => x.Parent)
.WillCascadeOnDelete(true);
或使用包含
var adv = db.Adv.Include(b => b.Features)
.Include(b => b.AdvDetails)
.Include(b => b.AdvGallery)
.FirstOrDefault(b => b.Id == id);
db.Adv.Remove(adv);
for .HasMany(...)。WithMany(...)Include还可以
在EF Core中,构建器中的语法如下:
builder.HasOne(b => b.Parent )
.WithMany(a => a.Children)
.OnDelete(DeleteBehavior.Cascade);
https://docs.microsoft.com/en-us/ef/core/saving/cascade-delete