在 Efcore 中包含子过滤器未按预期工作

Question

我正在使用 EFCore 5 并且我遵循结构

public class User: AuditableEntity
{
   public string Id { get; set; }
   public string Discriminator { get; set; }
   public User()
   {
   }
}

public class CustomerUser: User
{
   public string CustomerId { get; set; }
   // public bool? IsAdmin { get; set; }
   public Customer Customer { get; set; }
}

public class CustomerAdmin: CustomerUser
{
   
}

public class Customer: AuditableEntity
{
   ...
   public ICollection<CustomerUser> CustomerUsers { get; private set; }
   ...
}

我正在使用 LINQ 查询来获取基于子类类型的关系。有人认为我必须使用鉴别器列。

await _dbContext.Customers
    .Include(x => x.CustomerUsers.Where(u => u is CustomerAdmin))
    .Select(x => new TmpQueryResult
    {
        CustomerId = x.Id,
        UserInfo = x.CustomerUsers.Select(y => new UserInfo
        {
            Id = y.Id,
            IsAdmin = y is CustomerAdmin
        })
    })
    .FirstOrDefaultAsync(x => x.CustomerId == request.CustomerId);;

生成的查询是

Executed DbCommand (30ms) [Parameters=[@__request_CustomerId_0='16d2d324-0aac-4c9e-af3a-fef537a4de70' (Size = 255)], CommandType='Text', CommandTimeout='30']
    SELECT `t`.`Id`, `t0`.`Id`, `t0`.`IsAdmin`
    FROM (
        SELECT `c`.`Id`
        FROM `Customers` AS `c`
        WHERE `c`.`Id` = @__request_CustomerId_0
        LIMIT 1
    ) AS `t`
    LEFT JOIN (
        SELECT `u`.`Id`, `u`.`Discriminator` = 'CustomerAdmin' AS `IsAdmin`, `u`.`CustomerId`
        FROM `Users` AS `u`
        WHERE `u`.`Discriminator` IN ('CustomerUser', 'CustomerAdmin', 'OfficeManager', 'Provider')
    ) AS `t0` ON `t`.`Id` = `t0`.`CustomerId`
    ORDER BY `t`.`Id`, `t0`.`Id`

u => u is CustomerAdmin 没有被翻译成鉴别器` IN ('CustomerAdmin')

我正在使用 Pomelo.EntityFrameworkCore.MySql 版本 5.0.0。我不明白为什么它没有按预期工作，或者我在这里做错了什么。

Answer 1

对于自定义投影 Include 被完全忽略，所以你必须在投影中重复你的鉴别器过滤器。

await _dbContext.Customers
    .Select(x => new TmpQueryResult
    {
        CustomerId = x.Id,
        UserInfo = x.CustomerUsers
            .Where(u => u is CustomerAdmin)
            .Select(y => new UserInfo
            {
                Id = y.Id,
                IsAdmin = y is CustomerAdmin
            })
    })
    .FirstOrDefaultAsync(x => x.CustomerId == request.CustomerId);;

在 Efcore 中包含子过滤器未按预期工作

In Efcore Include with filter by child not working as expected

entity-framework-core

.net-core

ef-core-5.0