Question

所以，我已经被困了好几个小时试图在我的模型中包含两个嵌套集合用于WebAPI。经过数小时的反复试验，搜索，阅读以及更多的反复试验，我仍然无法弄清楚如何正确地做到这一点。

我使用MySQL作为数据库。

我的模型关系如下：

Account <-1:m-> Character
Character <-m:1-> Corporation
Corporation <-1:m-> CorporationWallet
Corporation <-1:m-> CorporationTaxes

该模型是通过EF Code-First设置的，它在数据库中工作，导航关系也正常。

我想要完成的是获取一个帐户及其角色，每个角色应该包括他们的公司以及公司的钱包和税收。

以下工作和提取所需的一切，除税：

Account account = db.Accounts
    .Include(x => x.Characters.Select(y => y.Corporation.Wallets))
    .Where(o => o.AccessToken == accessToken)
    .Take(1)
    .ToList()
    .FirstOrDefault();

但是，如果我希望纳税，它会引发例外并且不会继续：

Account account = db.Accounts
    .Include(x => x.Characters.Select(y => y.Corporation.Wallets))
    .Include(x => x.Characters.Select(y => y.Corporation.Taxes))
    .Where(o => o.AccessToken == accessToken)
    .Take(1)
    .ToList()
    .FirstOrDefault();

失败，出现以下异常：

An error occurred while executing the command definition. See the inner exception for details.

内部异常：

<Message>An error has occurred.</Message>
<ExceptionMessage>Unknown column 'UnionAll1.C1' in 'field list'</ExceptionMessage>
<ExceptionType>MySql.Data.MySqlClient.MySqlException</ExceptionType>
<StackTrace>
at MySql.Data.MySqlClient.MySqlStream.ReadPacket()
at MySql.Data.MySqlClient.NativeDriver.GetResult(Int32& affectedRow, Int64& insertedId)
at MySql.Data.MySqlClient.Driver.GetResult(Int32 statementId, Int32& affectedRows, Int64& insertedId)
at MySql.Data.MySqlClient.Driver.NextResult(Int32 statementId, Boolean force)
at MySql.Data.MySqlClient.MySqlDataReader.NextResult()
at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
at MySql.Data.Entity.EFMySqlCommand.ExecuteDbDataReader(CommandBehavior behavior)
at System.Data.Common.DbCommand.ExecuteReader(CommandBehavior behavior)
at System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.<Reader>b__c(DbCommand t, DbCommandInterceptionContext`1 c)
at System.Data.Entity.Infrastructure.Interception.InternalDispatcher`1.Dispatch[TTarget,TInterceptionContext,TResult](TTarget target, Func`3 operation, TInterceptionContext interceptionContext, Action`3 executing, Action`3 executed)
at System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.Reader(DbCommand command, DbCommandInterceptionContext interceptionContext)
at System.Data.Entity.Internal.InterceptableDbCommand.ExecuteDbDataReader(CommandBehavior behavior) at System.Data.Common.DbCommand.ExecuteReader(CommandBehavior behavior)
at System.Data.Entity.Core.EntityClient.Internal.EntityCommandDefinition.ExecuteStoreCommands(EntityCommand entityCommand, CommandBehavior behavior)
</StackTrace>

如果我能提供更多信息，请告诉我。

提前感谢您的帮助。

编辑1：

以下内容给出了相同的异常和错误：

var query = from acc in db.Accounts
            where acc.AccessToken == accessToken
            select new
            {
                acc,
                Characters = from cha in acc.Characters
                             select new
                             {
                                 cha,
                                 Account = cha.Account,
                                 Corporation = cha.Corporation,
                                 Taxes = from tax in cha.Corporation.Taxes
                                         select new
                                         {
                                             tax,
                                             Corporation = tax.Corporation
                                         },
                                 Wallets = from wallet in cha.Corporation.Wallets
                                           select new
                                           {
                                               wallet,
                                               Corporation = wallet.Corporation
                                           }
                             }
            };
Account account = query
    .Select(x => x.acc)
    .FirstOrDefault()

Answer 1

正如贾尼娜在评论中指出的那样，我的导航属性有些混乱。

我正在使用

[InverseProperty("Corporation")]
public List<CorporationTax> Taxes { get; set; }
[InverseProperty("Corporation")]
public List<CorporationWallet> Wallets { get; set; }

而不是

[InverseProperty("Corporation")]
public virtual ICollection<CorporationTax> Taxes { get; set; }
[InverseProperty("Corporation")]
public virtual ICollection<CorporationWallet> Wallets { get; set; }

在我的模型层修复所有导航集合属性后，我能够通过

获取我想要的所有内容

Account account = db.Accounts
    .Where(o => o.AccessToken == accessToken)
    .Take(1)
    .ToList()
    .FirstOrDefault();

Answer 2

使用以下

Account account = db.Accounts
    .Include(x => x.Characters)
    .Where(o => o.AccessToken == accessToken)
    .Take(1)
    .ToList()
    .FirstOrDefault();

因为Taxes和Wallets属于同一导航属性，所以您不需要包含agian

然后你可以从角色模型中获得每个属性

EF6 LINQ嵌套包括

2 个答案: