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>();

我的案例使用了存储过程而不是原始SQL

创建一个类

Public class School
{
    [Key]
    public Guid SchoolId { get; set; }
    public string Name { get; set; }
    public string Branch { get; set; }
    public int NumberOfStudents  { get; set; }
}

下面在我的DbContext类上添加

public DbSet<School> SP_Schools { get; set; }

执行存储过程。

var MySchools = _db.SP_Schools.FromSqlRaw("GetSchools @schoolId, @page, @size ",
              new SqlParameter("schoolId", schoolId),
              new SqlParameter("page", page),
              new SqlParameter("size", size)))
.IgnoreQueryFilters();

你可以在EF Core中执行原始sql -将这个类添加到你的项目中。 这将允许您执行原始SQL并获得原始结果,而不必定义POCO和DBSet。 参见https://github.com/aspnet/EntityFramework/issues/1862#issuecomment-220787464获取原始示例。

using Microsoft.EntityFrameworkCore.Infrastructure;
using Microsoft.EntityFrameworkCore.Internal;
using Microsoft.EntityFrameworkCore.Storage;
using System.Threading;
using System.Threading.Tasks;

namespace Microsoft.EntityFrameworkCore
{
    public static class RDFacadeExtensions
    {
        public static RelationalDataReader ExecuteSqlQuery(this DatabaseFacade databaseFacade, string sql, params object[] parameters)
        {
            var concurrencyDetector = databaseFacade.GetService<IConcurrencyDetector>();

            using (concurrencyDetector.EnterCriticalSection())
            {
                var rawSqlCommand = databaseFacade
                    .GetService<IRawSqlCommandBuilder>()
                    .Build(sql, parameters);

                return rawSqlCommand
                    .RelationalCommand
                    .ExecuteReader(
                        databaseFacade.GetService<IRelationalConnection>(),
                        parameterValues: rawSqlCommand.ParameterValues);
            }
        }

        public static async Task<RelationalDataReader> ExecuteSqlQueryAsync(this DatabaseFacade databaseFacade, 
                                                             string sql, 
                                                             CancellationToken cancellationToken = default(CancellationToken),
                                                             params object[] parameters)
        {

            var concurrencyDetector = databaseFacade.GetService<IConcurrencyDetector>();

            using (concurrencyDetector.EnterCriticalSection())
            {
                var rawSqlCommand = databaseFacade
                    .GetService<IRawSqlCommandBuilder>()
                    .Build(sql, parameters);

                return await rawSqlCommand
                    .RelationalCommand
                    .ExecuteReaderAsync(
                        databaseFacade.GetService<IRelationalConnection>(),
                        parameterValues: rawSqlCommand.ParameterValues,
                        cancellationToken: cancellationToken);
            }
        }
    }
}

下面是一个如何使用它的例子:

// Execute a query.
using(var dr = await db.Database.ExecuteSqlQueryAsync("SELECT ID, Credits, LoginDate FROM SamplePlayer WHERE " +
                                                          "Name IN ('Electro', 'Nitro')"))
{
    // Output rows.
    var reader = dr.DbDataReader;
    while (reader.Read())
    {
        Console.Write("{0}\t{1}\t{2} \n", reader[0], reader[1], reader[2]);
    }
}

你可以用这个:

public static class SqlQueryExtensions
{
    public static IList<T> SqlQuery<T>(this DbContext db, string sql, params object[] parameters) where T : class
    {
        using (var db2 = new ContextForQueryType<T>(db.Database.GetDbConnection()))
        {
            // share the current database transaction, if one exists
            var transaction = db.Database.CurrentTransaction;
            if (transaction != null)
                db2.Database.UseTransaction(transaction.GetDbTransaction());
            return db2.Set<T>().FromSqlRaw(sql, parameters).ToList();
        }
    }

    private class ContextForQueryType<T> : DbContext where T : class
    {
        private readonly DbConnection connection;

        public ContextForQueryType(DbConnection connection)
        {
            this.connection = connection;
        }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            optionsBuilder.UseSqlServer(connection, options => options.EnableRetryOnFailure());

            base.OnConfiguring(optionsBuilder);
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<T>().HasNoKey();
            base.OnModelCreating(modelBuilder);
        }
    }
}

以及用法:

    using (var db = new Db())
    {
        var results = db.SqlQuery<ArbitraryType>("select 1 id, 'joe' name");
        //or with an anonymous type like this
        var results2 = db.SqlQuery(() => new { id =1, name=""},"select 1 id, 'joe' name");
    }