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?
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
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();
}
}
}
其他回答
我找到了EntityFrameworkCore包。RawSQLExtensions在github上。要使用它,添加nuget包。
<PackageReference Include="EntityFrameworkCore.RawSQLExtensions" Version="1.2.0" />
这个库没有文档,但下面是我在。net 6 + EF Core 6 + Npgsql 6中使用它
public class DbResult
{
public string Name { get; set; }
public int Age { get; set; }
}
using EntityFrameworkCore.RawSQLExtensions.Extensions;
var results = await context.Database
.SqlQuery<DbResult>(
@"select name, age from ""users"" where age > @Age",
new NpgsqlParameter("@Age", 15))
.ToListAsync();
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。
现在,直到EFCore有新的东西,我将使用命令 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避免Sql注入。
dbData.Product.FromSql("SQL SCRIPT");
FromSql不支持全查询。例如,如果你想包含一个WHERE子句,它将被忽略。
一些链接:
使用实体框架核心执行原始SQL查询
原始SQL查询
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");
}