与实体框架核心删除dbData.Database。我找不到一个解决方案来构建一个原始的SQL查询为我的全文搜索查询,将返回表数据和排名。

我所见过的在实体框架核心中构建原始SQL查询的唯一方法是通过dbData.Product。FromSql(“SQL脚本”);这是没有用的,因为我没有DbSet,将映射我在查询中返回的排名。

有什么想法?


当前回答

现在,直到EFCore有新的东西,我将使用命令 手动映射

  using (var command = this.DbContext.Database.GetDbConnection().CreateCommand())
  {
      command.CommandText = "SELECT ... WHERE ...> @p1)";
      command.CommandType = CommandType.Text;
      var parameter = new SqlParameter("@p1",...);
      command.Parameters.Add(parameter);

      this.DbContext.Database.OpenConnection();

      using (var result = command.ExecuteReader())
      {
         while (result.Read())
         {
            .... // Map to your entity
         }
      }
  }

尝试使用SqlParameter避免Sql注入。

 dbData.Product.FromSql("SQL SCRIPT");

FromSql不支持全查询。例如,如果你想包含一个WHERE子句,它将被忽略。

一些链接:

使用实体框架核心执行原始SQL查询

原始SQL查询

其他回答

这个解决方案很大程度上依赖于@pius的解决方案。我想添加支持查询参数的选项,以帮助减少SQL注入,我还想使它成为实体框架核心的DbContext DatabaseFacade的扩展,使它更加集成。

首先用扩展名创建一个新类:

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Infrastructure;
using Microsoft.EntityFrameworkCore.Metadata;
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.Linq;
using System.Threading.Tasks;

namespace EF.Extend
{

    public static class ExecuteSqlExt
    {
        /// <summary>
        /// Execute raw SQL query with query parameters
        /// </summary>
        /// <typeparam name="T">the return type</typeparam>
        /// <param name="db">the database context database, usually _context.Database</param>
        /// <param name="query">the query string</param>
        /// <param name="map">the map to map the result to the object of type T</param>
        /// <param name="queryParameters">the collection of query parameters, if any</param>
        /// <returns></returns>
        public static List<T> ExecuteSqlRawExt<T, P>(this DatabaseFacade db, string query, Func<DbDataReader, T> map, IEnumerable<P> queryParameters = null)
        {
            using (var command = db.GetDbConnection().CreateCommand())
            {
                if((queryParameters?.Any() ?? false))
                    command.Parameters.AddRange(queryParameters.ToArray());

                command.CommandText = query;
                command.CommandType = CommandType.Text;

                db.OpenConnection();

                using (var result = command.ExecuteReader())
                {
                    var entities = new List<T>();

                    while (result.Read())
                    {
                        entities.Add(map(result));
                    }

                    return entities;
                }
            }
                
        }
    }

}

注意上面的“T”是返回的类型,“P”是查询参数的类型,这取决于你是否使用MySql、Sql等。

接下来我们将展示一个例子。我使用的是MySql EF核心功能,所以我们将看到如何使用上面的通用扩展与这个更具体的MySql实现:

//add your using statement for the extension at the top of your Controller
//with all your other using statements
using EF.Extend;

//then your your Controller looks something like this
namespace Car.Api.Controllers
{

    //Define a quick Car class for the custom return type
    //you would want to put this in it's own class file probably
    public class Car
    {
        public string Make { get; set; }
        public string Model { get; set; }
        public string DisplayTitle { get; set; }
    }

    [ApiController]
    public class CarController : ControllerBase
    {
        private readonly ILogger<CarController> _logger;
        //this would be your Entity Framework Core context
        private readonly CarContext _context;

        public CarController(ILogger<CarController> logger, CarContext context)
        {
            _logger = logger;
            _context = context;
        }

        //... more stuff here ...

       /// <summary>
       /// Get car example
       /// </summary>
       [HttpGet]
       public IEnumerable<Car> Get()
       {
           //instantiate three query parameters to pass with the query
           //note the MySqlParameter type is because I'm using MySql
           MySqlParameter p1 = new MySqlParameter
           {
               ParameterName = "id1",
               Value = "25"
           };

           MySqlParameter p2 = new MySqlParameter
           {
               ParameterName = "id2",
               Value = "26"
           };

           MySqlParameter p3 = new MySqlParameter
           {
               ParameterName = "id3",
               Value = "27"
           };

           //add the 3 query parameters to an IEnumerable compatible list object
           List<MySqlParameter> queryParameters = new List<MySqlParameter>() { p1, p2, p3 };

           //note the extension is now easily accessed off the _context.Database object
           //also note for ExecuteSqlRawExt<Car, MySqlParameter>
           //Car is my return type "T"
           //MySqlParameter is the specific DbParameter type MySqlParameter type "P"
           List<Car> result = _context.Database.ExecuteSqlRawExt<Car, MySqlParameter>(
        "SELECT Car.Make, Car.Model, CONCAT_WS('', Car.Make, ' ', Car.Model) As DisplayTitle FROM Car WHERE Car.Id IN(@id1, @id2, @id3)",
        x => new Car { Make = (string)x[0], Model = (string)x[1], DisplayTitle = (string)x[2] }, 
        queryParameters);

           return result;
       }
    }
}

查询将返回如下行: “福特”,“探险家”,“福特探险家” “特斯拉”,“Model X”,“特斯拉Model X”

显示标题没有定义为数据库列,因此默认情况下它不是EF Car模型的一部分。作为众多可能的解决方案之一,我喜欢这种方法。本页上的其他答案引用了使用[NotMapped]装饰器解决此问题的其他方法,这取决于您的用例,可能是更合适的方法。

注意,本例中的代码显然比实际需要的更冗长,但我认为它使示例更清晰。

在其他答案的基础上,我写了这个助手来完成这个任务,包括示例用法:

public static class Helper
{
    public static List<T> RawSqlQuery<T>(string query, Func<DbDataReader, T> map)
    {
        using (var context = new DbContext())
        {
            using (var command = context.Database.GetDbConnection().CreateCommand())
            {
                command.CommandText = query;
                command.CommandType = CommandType.Text;

                context.Database.OpenConnection();

                using (var result = command.ExecuteReader())
                {
                    var entities = new List<T>();

                    while (result.Read())
                    {
                        entities.Add(map(result));
                    }

                    return entities;
                }
            }
        }
    }

用法:

public class TopUser
{
    public string Name { get; set; }

    public int Count { get; set; }
}

var result = Helper.RawSqlQuery(
    "SELECT TOP 10 Name, COUNT(*) FROM Users U"
    + " INNER JOIN Signups S ON U.UserId = S.UserId"
    + " GROUP BY U.Name ORDER BY COUNT(*) DESC",
    x => new TopUser { Name = (string)x[0], Count = (int)x[1] });

result.ForEach(x => Console.WriteLine($"{x.Name,-25}{x.Count}"));

我计划在添加内置支持后尽快摆脱它。根据EF核心团队的Arthur Vickers的声明,这是2.0后的优先级。这个问题正在被追踪。

在实体框架6中,你可以执行如下内容

创建模态类为

Public class User
{
        public int Id { get; set; }
        public string fname { get; set; }
        public string lname { get; set; }
        public string username { get; set; }
}

执行Raw DQL SQl命令如下所示:

var userList = datacontext.Database.SqlQuery<User>(@"SELECT u.Id ,fname , lname ,username FROM dbo.Users").ToList<User>();

查询数据:不存在实体

               string query = "SELECT r.Name as roleName, ur.roleId, u.Id as userId   FROM dbo.AspNetUserRoles AS ur INNER JOIN dbo.AspNetUsers AS u ON ur.UserId = u.Id INNER JOIN dbo.AspNetRoles AS r ON ur.RoleId = r.Id ";

               ICollection<object> usersWithRoles = new List<object>();
                using (var command = _identityDBContext.Database.GetDbConnection().CreateCommand())
                {
                    command.CommandText = query;
                    command.CommandType = CommandType.Text;

                    await _identityDBContext.Database.OpenConnectionAsync();

                    using (var reader = await command.ExecuteReaderAsync())
                    {      
                        while (await reader.ReadAsync())
                        {
                            usersWithRoles.Add(new { 
                                roleName = reader.GetFieldValueAsync<string>(0).Result, 
                                roleId = reader.GetFieldValueAsync<string>(1).Result,
                                userId = reader.GetFieldValueAsync<string>(2).Result
                            });
                        }    
                    }
                }

详细:

 [HttpGet]
    [Route("GetAllUsersWithRoles")]
    public async Task<IActionResult> GetAllUsersWithRoles()
    {
        string query = "SELECT r.Name as roleName, ur.roleId, u.Id as userId   FROM dbo.AspNetUserRoles AS ur INNER JOIN dbo.AspNetUsers AS u ON ur.UserId = u.Id INNER JOIN dbo.AspNetRoles AS r ON ur.RoleId = r.Id ";
        try
        {
            ICollection<object> usersWithRoles = new List<object>();
            using (var command = _identityDBContext.Database.GetDbConnection().CreateCommand())
            {
                command.CommandText = query;
                command.CommandType = CommandType.Text;

                await _identityDBContext.Database.OpenConnectionAsync();

                using (var reader = await command.ExecuteReaderAsync())
                {      
                    while (await reader.ReadAsync())
                    {
                        usersWithRoles.Add(new { 
                            roleName = reader.GetFieldValueAsync<string>(0).Result, 
                            roleId = reader.GetFieldValueAsync<string>(1).Result,
                            userId = reader.GetFieldValueAsync<string>(2).Result
                        });
                    }    
                }
            }
                return StatusCode(200, usersWithRoles); // Get all users   
        }
        catch (Exception e)
        {
            return StatusCode(500, e);
        }
    }

结果如下所示:

[
  {
    "roleName": "admin",
    "roleId": "7c9cb1be-e987-4ec1-ae4d-e4c9790f57d8",
    "userId": "12eadc86-6311-4d5e-8be8-df30799df265"
  },
  {
    "roleName": "user",
    "roleId": "a0d5ef46-b1e6-4a53-91ce-9ff5959f1ed8",
    "userId": "12eadc86-6311-4d5e-8be8-df30799df265"
  },
  {
    "roleName": "user",
    "roleId": "a0d5ef46-b1e6-4a53-91ce-9ff5959f1ed8",
    "userId": "3e7cd970-8c52-4dd1-847c-f824671ea15d"
  }
]

在Core 2.1中,你可以这样做:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
       modelBuilder.Query<Ranks>();
}

然后定义SQL过程,像这样:

public async Task<List<Ranks>> GetRanks(string value1, Nullable<decimal> value2)
{
    SqlParameter value1Input = new SqlParameter("@Param1", value1?? (object)DBNull.Value);
    SqlParameter value2Input = new SqlParameter("@Param2", value2?? (object)DBNull.Value);

    List<Ranks> getRanks = await this.Query<Ranks>().FromSql("STORED_PROCEDURE @Param1, @Param2", value1Input, value2Input).ToListAsync();

    return getRanks;
}

这样就不会在数据库中创建rank模型。

现在在你的控制器/动作中你可以调用:

List<Ranks> gettingRanks = _DbContext.GetRanks(value1,value2).Result.ToListAsync();

这样就可以调用原始SQL过程。