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

试试这个(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。net core 2.2和3.0中测试。

注意:该方案性能较慢

其他回答

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。

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();

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

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]);
    }
}

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();
}