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

添加Nuget包- Microsoft.EntityFrameworkCore.Relational

using Microsoft.EntityFrameworkCore;
...
await YourContext.Database.ExecuteSqlCommandAsync("... @p0, @p1", param1, param2 ..)

这将以int形式返回行号

参见- https://learn.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.relationaldatabasefacadeextensions.executesqlcommand?view=efcore-3.0

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EF核心你不再可以执行“自由”原始sql。您需要为该类定义一个POCO类和一个DbSet。 在你的情况下,你需要定义Rank:

var ranks = DbContext.Ranks
   .FromSql("SQL_SCRIPT OR STORED_PROCEDURE @p0,@p1,...etc", parameters)
   .AsNoTracking().ToList();

因为它肯定是只读的,所以包含. asnotracking()调用会很有用。

EF Core 3.0的突破性变化:

DbQuery()现在已经过时了,取而代之的应该是DbSet()。如果你有一个无键实体,即它不需要主键,你可以使用HasNoKey()方法:

ModelBuilder.Entity<SomeModel>().HasNoKey()

更多信息可以在这里找到

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。

我更新了扩展方法从@AminRostami返回IAsyncEnumerable(这样LINQ过滤可以应用),它的映射模型列名的记录从DB返回到模型(EF Core 5测试):

扩展本身:

public static class QueryHelper
{
    private static string GetColumnName(this MemberInfo info)
    {
        List<ColumnAttribute> list = info.GetCustomAttributes<ColumnAttribute>().ToList();
        return list.Count > 0 ? list.Single().Name : info.Name;
    }
    /// <summary>
    /// Executes raw query with parameters and maps returned values to column property names of Model provided.
    /// Not all properties are required to be present in model (if not present - null)
    /// </summary>
    public static async IAsyncEnumerable<T> ExecuteQuery<T>(
        [NotNull] this DbContext db,
        [NotNull] string query,
        [NotNull] params SqlParameter[] parameters)
        where T : class, new()
    {
        await using DbCommand command = db.Database.GetDbConnection().CreateCommand();
        command.CommandText = query;
        command.CommandType = CommandType.Text;
        if (parameters != null)
        {
            foreach (SqlParameter parameter in parameters)
            {
                command.Parameters.Add(parameter);
            }
        }
        await db.Database.OpenConnectionAsync();
        await using DbDataReader reader = await command.ExecuteReaderAsync();
        List<PropertyInfo> lstColumns = new T().GetType()
            .GetProperties(BindingFlags.DeclaredOnly | BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic).ToList();
        while (await reader.ReadAsync())
        {
            T newObject = new();
            for (int i = 0; i < reader.FieldCount; i++)
            {
                string name = reader.GetName(i);
                PropertyInfo prop = lstColumns.FirstOrDefault(a => a.GetColumnName().Equals(name));
                if (prop == null)
                {
                    continue;
                }
                object val = await reader.IsDBNullAsync(i) ? null : reader[i];
                prop.SetValue(newObject, val, null);
            }
            yield return newObject;
        }
    }
}

使用的模型(注意列名与实际的属性名不同):

public class School
{
    [Key] [Column("SCHOOL_ID")] public int SchoolId { get; set; }

    [Column("CLOSE_DATE", TypeName = "datetime")]
    public DateTime? CloseDate { get; set; }

    [Column("SCHOOL_ACTIVE")] public bool? SchoolActive { get; set; }
}

实际的用法:

public async Task<School> ActivateSchool(int schoolId)
{
    // note that we're intentionally not returning "SCHOOL_ACTIVE" with select statement
    // this might be because of certain IF condition where we return some other data
    return await _context.ExecuteQuery<School>(
        "UPDATE SCHOOL SET SCHOOL_ACTIVE = 1 WHERE SCHOOL_ID = @SchoolId; SELECT SCHOOL_ID, CLOSE_DATE FROM SCHOOL",
        new SqlParameter("@SchoolId", schoolId)
    ).SingleAsync();
}

不是直接针对OP的场景,但因为我一直在努力解决这个问题,我想放弃这些让DbContext更容易执行原始SQL的ex.方法:

public static class DbContextCommandExtensions
{
  public static async Task<int> ExecuteNonQueryAsync(this DbContext context, string rawSql,
    params object[] parameters)
  {
    var conn = context.Database.GetDbConnection();
    using (var command = conn.CreateCommand())
    {
      command.CommandText = rawSql;
      if (parameters != null)
        foreach (var p in parameters)
          command.Parameters.Add(p);
      await conn.OpenAsync();
      return await command.ExecuteNonQueryAsync();
    }
  }

  public static async Task<T> ExecuteScalarAsync<T>(this DbContext context, string rawSql,
    params object[] parameters)
  {
    var conn = context.Database.GetDbConnection();
    using (var command = conn.CreateCommand())
    {
      command.CommandText = rawSql;
      if (parameters != null)
        foreach (var p in parameters)
          command.Parameters.Add(p);
      await conn.OpenAsync();
      return (T)await command.ExecuteScalarAsync();
    }
  }
}