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

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。

其他回答

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");
    }

你也可以使用QueryFirst。和Dapper一样,这完全不在EF的范围内。与Dapper(或EF)不同的是,您不需要维护POCO,只需在真实环境中编辑sql sql,并根据DB不断对其进行重新验证。免责声明:我是QueryFirst的作者。

这样做的实体框架核心5,需要安装

Microsoft.EntityFrameworkCore.Relational

助手扩展方法

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Infrastructure;
using Microsoft.EntityFrameworkCore.Storage;
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;


public static class EfHelper
{
    public static DbTransaction GetDbTransaction(this IDbContextTransaction source)
    {
        return (source as IInfrastructure<DbTransaction>).Instance;
    }

    private class PropertyMapp
    {
        public string Name { get; set; }
        public Type Type { get; set; }

        public bool IsSame(PropertyMapp mapp)
        {
            if (mapp == null)
            {
                return false;
            }
            bool same = mapp.Name == Name && mapp.Type == Type;
            return same;
        }
    }

    public static IEnumerable<T> FromSqlQuery<T>(this DbContext context, string query, params object[] parameters) where T : new()
    {
        const BindingFlags flags = BindingFlags.Public | BindingFlags.Instance | BindingFlags.NonPublic;
        List<PropertyMapp> entityFields = (from PropertyInfo aProp in typeof(T).GetProperties(flags)
                                           select new PropertyMapp
                                           {
                                               Name = aProp.Name,
                                               Type = Nullable.GetUnderlyingType(aProp.PropertyType) ?? aProp.PropertyType
                                           }).ToList();
        List<PropertyMapp> dbDataReaderFields = new List<PropertyMapp>();
        List<PropertyMapp> commonFields = null;

        using (var command = context.Database.GetDbConnection().CreateCommand())
        {
            if (command.Connection.State != ConnectionState.Open)
            {
                command.Connection.Open();
            }
            var currentTransaction = context.Database.CurrentTransaction;
            if (currentTransaction != null)
            {
                command.Transaction = currentTransaction.GetDbTransaction();
            }
            command.CommandText = query;
            if (parameters.Any())
            {
                command.Parameters.AddRange(parameters);
            }
            using (var result = command.ExecuteReader())
            {
                while (result.Read())
                {
                    if (commonFields == null)
                    {
                        for (int i = 0; i < result.FieldCount; i++)
                        {
                            dbDataReaderFields.Add(new PropertyMapp { Name = result.GetName(i), Type = result.GetFieldType(i) });
                        }
                        commonFields = entityFields.Where(x => dbDataReaderFields.Any(d => d.IsSame(x))).Select(x => x).ToList();
                    }

                    var entity = new T();
                    foreach (var aField in commonFields)
                    {
                        PropertyInfo propertyInfos = entity.GetType().GetProperty(aField.Name);
                        var value = (result[aField.Name] == DBNull.Value) ? null : result[aField.Name]; //if field is nullable
                        propertyInfos.SetValue(entity, value, null);
                    }
                    yield return entity;
                }
            }
        }
    }

    /*
     * https://entityframeworkcore.com/knowledge-base/35631903/raw-sql-query-without-dbset---entity-framework-core
     */
    public static IEnumerable<T> FromSqlQuery<T>(this DbContext context, string query, Func<DbDataReader, T> map, params object[] parameters)
    {
        using (var command = context.Database.GetDbConnection().CreateCommand())
        {
            if (command.Connection.State != ConnectionState.Open)
            {
                command.Connection.Open();
            }
            var currentTransaction = context.Database.CurrentTransaction;
            if (currentTransaction != null)
            {
                command.Transaction = currentTransaction.GetDbTransaction();
            }
            command.CommandText = query;
            if (parameters.Any())
            {
                command.Parameters.AddRange(parameters);
            }
            using (var result = command.ExecuteReader())
            {
                while (result.Read())
                {
                    yield return map(result);
                }
            }
        }
    }
}

模型

public class UserModel
{
    public string Name { get; set; }
    public string Email { get; set; }
    public bool? IsDeleted { get; set; }
}

手动映射

List<UserModel> usersInDb = Db.FromSqlQuery
(
    "SELECT Name, Email FROM Users WHERE Name=@paramName",
    x => new UserModel 
    { 
        Name = (string)x[0], 
        Email = (string)x[1] 
    },
    new SqlParameter("@paramName", user.Name)
)
.ToList();

usersInDb = Db.FromSqlQuery
(
    "SELECT Name, Email FROM Users WHERE Name=@paramName",
    x => new UserModel 
    { 
        Name = x["Name"] is DBNull ? "" : (string)x["Name"], 
        Email = x["Email"] is DBNull ? "" : (string)x["Email"] 
    },
    new SqlParameter("@paramName", user.Name)
)
.ToList();

使用反射自动映射

List<UserModel> usersInDb = Db.FromSqlQuery<UserModel>
(
    "SELECT Name, Email, IsDeleted FROM Users WHERE Name=@paramName",
    new SqlParameter("@paramName", user.Name)
)
.ToList();

我使用Dapper绕过了Entity框架Core的这个约束。

IDbConnection.Query

正在处理带有多个参数的SQL查询或存储过程。 顺便说一下,它更快一些(参见基准测试)

Dapper很容易学。编写和运行带参数的存储过程需要15分钟。无论如何,你可以同时使用EF和Dapper。下面是一个例子:

 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();
        }


        }
}

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