[英]EF7 How to handle the update operation for nested entities
我試圖找出更新實體及其所有子實體時的最佳實踐。 例如; 我有一個“雇主”更新服務,它將更新雇主實體和雇主的“地址”實體以及每個“地址”的“電話”實體。 用戶可以向現有雇主添加新地址,或者他們可以更新當前地址,或者他們可以刪除一些地址,同樣適用於每個地址的電話。 你能幫我寫出處理這種情況的理想代碼嗎?
我正在使用EF7 rc1,我使用Automapper將Dto映射到我的服務中的實體。
public partial class Employer
{
public int EmployerId { get; set; }
public int Name { get; set; }
[InverseProperty("Employer")]
public virtual ICollection<Address> Address { get; set; }
}
public partial class Address
{
public int AddressId { get; set; }
public int Address1{ get; set; }
public int City { get; set; }
[ForeignKey("EmployerId")]
[InverseProperty("Address")]
public virtual Employer Employer { get; set; }
[InverseProperty("Address")]
public virtual ICollection<Phone> Phone { get; set; }
}
public partial class Phone
{
public int PhoneId { get; set; }
public string Number { get; set; }
[ForeignKey("AddressId")]
[InverseProperty("Phone")]
public virtual Address Address { get; set; }
}
我的服務方式;
public async Task<IServiceResult> Update(EmployerDto employer)
{
var employerDbEntity = await _db.Employer
.Include(a=>a.Address).ThenInclude(p=>p.Phone)
.SingleOrDefaultAsync (a=>a.EmployerId == employer.EmployerId);
//How to handle the update operation for children?
var entity = Mapper.Map<Employer>(employer);
HandleChildren(employerDbEntity,entity);
await _db.SaveChangesAsync();
...
...
}
private void HandleChildren(Employer employerDbEntity,Employer entity)
{
//Delete
foreach (var existing in employerDbEntity.Address.ToList())
{
if (!entity.Address.Any(a => a.AddressId == existing.AddressId))
employerDbEntity.Address.Remove(existing);
}
//Update or Insert
foreach (var address in entity.Address)
{
var existing = employerDbEntity.Address.SingleOrDefault(a =>a.AddressId == address.AddressId);
//Insert
if (existing == null)
{
employerDbEntity.Address.Add(address);
}
//Update
else
{
Mapper.Map(address, existing);
}
}
}
這個例子看起來像處理子集合的好方法。 必須手動檢查每個集合以執行所執行的操作。 (使用泛型聽起來不錯,但總是以某種方式咬回來。通常,性能。)
考慮到這一點,這里有一些建議:
以下是使用建議的示例:
private async Task UpdateAddresses(List<Address> addressesToUpdate)
{
using(var context = new Context())
{
var existingAddressIds = await context.Addresses
.Where(a => addressesToUpdate.Contains(a.AddressId))
.ToListAsync()
.ConfigureAwait(false);
existingAddressIds.ForEach(a => context.Addresses.Remove(a));
await context.SaveChangesAsync().ConfigureAwait(false);
}
}
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.