Question

使用Entity Framework Core删除dbData.Database.SqlQuery<SomeModel>我无法找到为我的全文搜索查询构建原始SQL查询的解决方案，该查询将返回表数据以及排名。

我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 SCRIPT");这不是很有用，因为我没有DbSet可以映射我在查询。

任何想法???

Answer 1

如果您使用自2018年7月7日起提供的EF Core 2.1 Release Candidate 1，您可以利用建议的新功能，即查询类型。

什么是query type？

除了实体类型，EF Core模型还可以包含查询类型，可用于对数据进行数据库查询未映射到实体类型。

何时使用查询类型？

用作ad hoc FromSql（）查询的返回类型。

映射到数据库视图。

映射到未定义主键的表。

映射到模型中定义的查询。

所以你不再需要做所有的黑客或解决方案作为你的问题的答案。只需按照以下步骤操作：

首先，您定义了类型为DbQuery<T>的新属性，其中T是将携带SQL查询的列值的类的类型。所以在你的DbContext中你会得到这个：

public DbQuery<SomeModel> SomeModels { get; set; }

其次使用FromSql方法，就像使用DbSet<T>：

一样

var result = context.SomeModels.FromSql("SQL_SCRIPT").ToList();
var result = await context.SomeModels.FromSql("SQL_SCRIPT").ToListAsync();

另请注意，DBContexts为partial classes，因此您可以创建一个或多个单独的文件来组织最适合您的“原始SQL DbQuery”定义。

Answer 2

在EF Core中，您不再可以执行“免费”原始sql。您需要为该类定义POCO类和DbSet。在您的情况下，您需要定义 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()电话会很有用。

Answer 3

您可以在EF Core中执行原始sql - 将此类添加到您的项目中。这将允许您执行原始SQL并获得原始结果，而无需定义POCO和DBSet。有关原始示例，请参阅https://github.com/aspnet/EntityFramework/issues/1862#issuecomment-220787464。

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);
            }
        }
    }
}

以下是如何使用它的示例：

// 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]);
    }
}

Answer 4

在其他答案的基础上，我编写了这个帮助程序来完成任务，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立即将其删除。根据来自EF Core团队的Arthur Vickers的statement，这是2.0后的优先考虑事项。正在跟踪问题here。

Answer 5

目前，在EFCore有新内容之前我会使用一个命令并手动映射

  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来避免Sql注入。

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

FromSql不能使用完整查询。示例如果要包含将被忽略的WHERE子句。

一些链接：

Executing Raw SQL Queries using Entity Framework Core

Raw SQL Queries

Answer 6

在Core 2.1中，您可以执行以下操作：

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

然后定义SQL过程，如：

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;
}

这样就不会在你的数据库中创建Ranks模型。

现在，在您的控制器/操作中，您可以致电：

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

这样您就可以调用Raw SQL Procedures。

Answer 7

您可以使用此命令（来自https://github.com/aspnet/EntityFrameworkCore/issues/1862#issuecomment-451671168）：

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()))
        {
            return db2.Query<T>().FromSql(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)
        {
            // switch on the connection type name to enable support multiple providers
            // var name = con.GetType().Name;
            optionsBuilder.UseSqlServer(connection, options => options.EnableRetryOnFailure());

            base.OnConfiguring(optionsBuilder);
        }

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

Answer 8

实际上，您可以创建一个通用存储库并执行类似的操作

public class GenericRepository<TEntity> : IGenericRepository<TEntity> where TEntity : BaseEntity
{
    private readonly DataContext context;
    private readonly DbSet<TEntity> dbSet;

    public GenericRepository(DataContext context)
    {
        this.context = context;
        this.dbSet = context.Set<TEntity>();
    }

   
    public IEnumerable<TEntity> ExecuteCommandQuery(string command)
        => dbSet.FromSqlRaw(command);

}

Answer 9

如果您只想运行查询并希望返回int。 EFCore 2具有DbContext.Database.ExecuteSqlCommand("Yourqueryhere")方法。

编辑：

ExecuteSqlCommand和ExecuteSqlCommandAsync在Microsoft.EntityFrameworkCore.Relational命名空间中定义。确保引用了它。

Answer 10

我的案例使用存储过程而不是原始SQL

创建了一个课程

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

在我的DbContext课堂上添加了以下内容

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

要执行存储过程：

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

Answer 11

我从@AminRostami 更新了扩展方法以返回 IAsyncEnumerable（因此可以应用 LINQ 过滤）并且它将从数据库返回的记录的模型列名称映射到模型（使用 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; }
}

实际使用情况：

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();
}

Answer 12

此解决方案在很大程度上取决于@pius的解决方案。我想添加支持查询参数的选项，以帮助减轻SQL注入，我还想使其成为DbContext DatabaseFacade for Entity Framework Core的扩展，以使其更加集成。

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;
                }
            }
                
        }
    }

}

在上面请注意，“ T”是返回的类型，“ P”是查询参数的类型，这取决于您是否使用MySql，Sql等。

接下来，我们将显示一个示例。我正在使用MySql EF Core功能，因此我们将看到如何在上述更具体的MySql实现中使用上述通用扩展名：

//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;
       }
    }
}

查询将返回以下行：
“福特”，“资源管理器”，“福特资源管理器”
“ Tesla”，“ Model X”，“ Tesla Model X”

显示标题未定义为数据库列，因此默认情况下它不属于EF Car模型。我喜欢这种方法作为许多可能的解决方案之一。本页上的其他答案引用了其他方法来使用[NotMapped]装饰器解决此问题，根据您的使用情况，这可能是更合适的方法。

请注意，此示例中的代码显然比所需的更加冗长，但我认为它使示例更清晰。

Answer 13

我知道这是一个老问题，但是也许它可以帮助某人调用存储过程而无需将DTO添加为DbSet。

https://stackoverflow.com/a/62058345/3300944

Answer 14

尝试一下：（创建扩展方法）

public static List<T> ExecuteQuery<T>(this dbContext db, string query) where T : class, new()
        {
            using (var command = db.Database.GetDbConnection().CreateCommand())
            {
                command.CommandText = query;
                command.CommandType = CommandType.Text;

                db.Database.OpenConnection();

                using (var reader = command.ExecuteReader())
                {
                    var lst = new List<T>();
                    var lstColumns = new T().GetType().GetProperties(BindingFlags.DeclaredOnly | BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic).ToList();
                    while (reader.Read())
                    {
                        var newObject = new T();
                        for (var i = 0; i < reader.FieldCount; i++)
                        {
                            var name = reader.GetName(i);
                            PropertyInfo prop = lstColumns.FirstOrDefault(a => a.Name.ToLower().Equals(name.ToLower()));
                            if (prop == null)
                            {
                                continue;
                            }
                            var val = reader.IsDBNull(i) ? null : reader[i];
                            prop.SetValue(newObject, val, null);
                        }
                        lst.Add(newObject);
                    }

                    return lst;
                }
            }
        }

用法：

var db = new dbContext();
string query = @"select ID , Name from People where ... ";
var lst = db.ExecuteQuery<PeopleView>(query);

我的模型：（不在DbSet中）：

public class PeopleView
{
    public int ID { get; set; }
    public string Name { get; set; }
}

在.netCore 2.2 and 3.0中进行了测试。

注意：该解决方案的性能较慢

Answer 15

使用Entity Framework 6，您可以执行以下操作

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; }
}

执行原始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>();

Answer 16

不直接针对OP的场景，但是由于我一直在为此苦苦挣扎，所以我想删除这些ex。使使用DbContext执行原始SQL更加容易的方法：

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();
    }
  }
}

Answer 17

您也可以使用QueryFirst。像Dapper一样，这完全在EF之外。与Dapper（或EF）不同，您不需要维护POCO，您可以在真实的环境中编辑sql SQL，并且可以根据数据库不断对其进行重新验证。免责声明：我是QueryFirst的作者。

Answer 18

我使用Dapper绕过了实体框架核心的约束。

IDbConnection.Query

正在使用带有多个参数的sql查询或存储过程。顺便说一下，它要快一些（请参阅benchmark tests）

Dapper很容易学习。使用参数编写和运行存储过程花了15分钟。无论如何，您都可以同时使用EF和Dapper。下面是一个示例：

 public class PodborsByParametersService
{
    string _connectionString = null;


    public PodborsByParametersService(string connStr)
    {
        this._connectionString = connStr;

    }

    public IList<TyreSearchResult> GetTyres(TyresPodborView pb,bool isPartner,string partnerId ,int pointId)
    {

        string sqltext  "spGetTyresPartnerToClient";

        var p = new DynamicParameters();
        p.Add("@PartnerID", partnerId);
        p.Add("@PartnerPointID", pointId);

        using (IDbConnection db = new SqlConnection(_connectionString))
        {
            return db.Query<TyreSearchResult>(sqltext, p,null,true,null,CommandType.StoredProcedure).ToList();
        }


        }
}

没有DbSet的原始SQL查询 - 实体框架核心

18 个答案: