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
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();
其他回答
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();
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
查询数据:不存在实体
string query = "SELECT r.Name as roleName, ur.roleId, u.Id as userId FROM dbo.AspNetUserRoles AS ur INNER JOIN dbo.AspNetUsers AS u ON ur.UserId = u.Id INNER JOIN dbo.AspNetRoles AS r ON ur.RoleId = r.Id ";
ICollection<object> usersWithRoles = new List<object>();
using (var command = _identityDBContext.Database.GetDbConnection().CreateCommand())
{
command.CommandText = query;
command.CommandType = CommandType.Text;
await _identityDBContext.Database.OpenConnectionAsync();
using (var reader = await command.ExecuteReaderAsync())
{
while (await reader.ReadAsync())
{
usersWithRoles.Add(new {
roleName = reader.GetFieldValueAsync<string>(0).Result,
roleId = reader.GetFieldValueAsync<string>(1).Result,
userId = reader.GetFieldValueAsync<string>(2).Result
});
}
}
}
详细:
[HttpGet]
[Route("GetAllUsersWithRoles")]
public async Task<IActionResult> GetAllUsersWithRoles()
{
string query = "SELECT r.Name as roleName, ur.roleId, u.Id as userId FROM dbo.AspNetUserRoles AS ur INNER JOIN dbo.AspNetUsers AS u ON ur.UserId = u.Id INNER JOIN dbo.AspNetRoles AS r ON ur.RoleId = r.Id ";
try
{
ICollection<object> usersWithRoles = new List<object>();
using (var command = _identityDBContext.Database.GetDbConnection().CreateCommand())
{
command.CommandText = query;
command.CommandType = CommandType.Text;
await _identityDBContext.Database.OpenConnectionAsync();
using (var reader = await command.ExecuteReaderAsync())
{
while (await reader.ReadAsync())
{
usersWithRoles.Add(new {
roleName = reader.GetFieldValueAsync<string>(0).Result,
roleId = reader.GetFieldValueAsync<string>(1).Result,
userId = reader.GetFieldValueAsync<string>(2).Result
});
}
}
}
return StatusCode(200, usersWithRoles); // Get all users
}
catch (Exception e)
{
return StatusCode(500, e);
}
}
结果如下所示:
[
{
"roleName": "admin",
"roleId": "7c9cb1be-e987-4ec1-ae4d-e4c9790f57d8",
"userId": "12eadc86-6311-4d5e-8be8-df30799df265"
},
{
"roleName": "user",
"roleId": "a0d5ef46-b1e6-4a53-91ce-9ff5959f1ed8",
"userId": "12eadc86-6311-4d5e-8be8-df30799df265"
},
{
"roleName": "user",
"roleId": "a0d5ef46-b1e6-4a53-91ce-9ff5959f1ed8",
"userId": "3e7cd970-8c52-4dd1-847c-f824671ea15d"
}
]
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();
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();
}
}
}
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