EF Core中执行Sql语句查询操作之FromSql，ExecuteSqlCommand，SqlQuery

    //执行sql查询语句 FromSql()
    QLLB_SWXContext _Context = new QLLB_SWXContext();
    string sql = "select * from Article where CategoryID=1;";
    List<Article> list = _Context.Article.FromSql(sql).ToList();
    foreach (var item in list)
    {
        Console.WriteLine(item.Title);
    }

示例代码2：视图中的查询

---创建视图，查询没有分配角色的菜单
create view view_NoRole
as 
select * from Sys_Navigation
where NavID not in (
select distinct  NavID   from Sys_Role_Nav 
)

//查询视图
    string sql2 = "select * from view_NoRole";
    List<SysNavigation> roleList = _Context.SysNavigation.FromSql(sql2).ToList();
    foreach (var item in roleList)
    {
        Console.WriteLine(item.Title);
    }

2.ExecuteSqlCommand，执行Sql操作处理

QLLB_SWXContext _Context = new QLLB_SWXContext();
//执行数据操作sql,返回受影响的行数
string sql = "update Sys_Role set SortValue=1 ;";
int count = _Context.Database.ExecuteSqlCommand(sql);
Console.WriteLine(count);

3.自定义SqlQuery，执行列表查询，在上线文中不存的对象。

示例代码1:

QLLB_SWXContext _Context = new QLLB_SWXContext();
//特别说明，自定义分装的不支持 单个值查询
//不支持object 查询
//自定义查询操作 SqlQuery
string sql = "select sum(ViewCount)*1.11 as allCount from Article;";
TempData result = _Context.Database.SqlQuery<TempData>(sql).FirstOrDefault();
Console.WriteLine(result.AllCount);

对象定义

public class TempData
{
    public int CategoryID { get; set; }
    public string Title { get; set; }
    public int ArtCount { get; set; }
    /// <summary>
    /// 求和结果
    /// </summary>
    public decimal AllCount { get; set; }
}

示例代码2：

执行视图查询：

--定义视图，文章分类和对应分类的文章数量
create view view_CateCount
as
select C.CategoryID,C.Title,  (
select count(*) from Article where CategoryID=C.CategoryID
) as ArtCount  from ArticleCategory C;

C#代码：

//组合查询
string sql2 = "select * from view_CateCount;";
List<TempData> tempList = _Context.Database.SqlQuery<TempData>(sql2).ToList();
foreach (var item in tempList)
{
    Console.WriteLine(item.Title);
}

SqlQuery扩展定义：

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Infrastructure;
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.Data.SqlClient;
using System.Reflection;
using System.Text;

namespace QL.Card.Entity
{
    public static class DbContextExtensions
    {
        private static void CombineParams(ref DbCommand command, params object[] parameters)
        {
            if (parameters != null)
            {
                foreach (SqlParameter parameter in parameters)
                {
                    if (!parameter.ParameterName.Contains("@"))
                        parameter.ParameterName = $"@{parameter.ParameterName}";
                    command.Parameters.Add(parameter);
                }
            }
        }

        private static DbCommand CreateCommand(DatabaseFacade facade, string sql, out DbConnection dbConn, params object[] parameters)
        {
            DbConnection conn = facade.GetDbConnection();
            dbConn = conn;
            conn.Open();
            DbCommand cmd = conn.CreateCommand();
            if (facade.IsSqlServer())
            {
                cmd.CommandText = sql;
                CombineParams(ref cmd, parameters);
            }
            return cmd;
        }

        public static DataTable SqlQuery(this DatabaseFacade facade, string sql, params object[] parameters)
        {
            DbCommand cmd = CreateCommand(facade, sql, out DbConnection conn, parameters);
            DbDataReader reader = cmd.ExecuteReader();
            DataTable dt = new DataTable();
            dt.Load(reader);
            reader.Close();
            conn.Close();
            return dt;
        }

        public static IEnumerable<T> SqlQuery<T>(this DatabaseFacade facade, string sql, params object[] parameters) where T : class, new()
        {
            DataTable dt = SqlQuery(facade, sql, parameters);
            return dt.ToEnumerable<T>();
        }

        public static IEnumerable<T> ToEnumerable<T>(this DataTable dt) where T : class, new()
        {
            PropertyInfo[] propertyInfos = typeof(T).GetProperties();
            T[] ts = new T[dt.Rows.Count];
            int i = 0;
            foreach (DataRow row in dt.Rows)
            {
                T t = new T();
                foreach (PropertyInfo p in propertyInfos)
                {
                    if (dt.Columns.IndexOf(p.Name) != -1 && row[p.Name] != DBNull.Value)
                        p.SetValue(t, row[p.Name], null);
                }
                ts[i] = t;
                i++;
            }
            return ts;
        }
    }
}

EF Core中执行Sql语句查询操作之FromSql，ExecuteSqlCommand，SqlQuery

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