Entityframework core where条件，执行的sql字符串及其结果
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【中文标题】Entityframework core where条件，执行的sql字符串及其结果【英文标题】：Entityframework core where condition, sql string that executed and its result 【发布时间】：2021-11-26 12:24:57 【问题描述】：我实现了一个 api 并使用了 EF 核心。
我有一个复杂的结构，它的核心实体是一个我称之为项目的实体。 我应该说我使用 EF Core 作为 DB First。然后我首先创建了我的数据库，之后我使用“Scaffold-Database”在代码中创建了我的模型。
项目的模型是：
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations.Schema;
namespace myProj_Model.Entities
public partial class Projects
public Projects()
Boreholes = new HashSet<Boreholes>();
ProjectsWorkAmounts = new HashSet<ProjectsWorkAmount>();
Zones = new HashSet<Zones>();
public long Id get; set;
public string Number get; set;
public string Name get; set;
public string Description get; set;
public string ClientName get; set;
public int? NoOfRecord get; set;
public byte[] Logo get; set;
public int? LogoWidth get; set;
public int? LogoHeight get; set;
public string Version get; set;
public byte? Revision get; set;
public byte? WorkValueIsLimit get; set;
public long? CreatedBy get; set;
public DateTime? CreatedDate get; set;
public long? ModifiedBy get; set;
public DateTime? ModifiedDate get; set;
public virtual Users CreatedBy_User get; set;
public virtual Users ModifiedBy_User get; set;
public virtual ProjectsDrillingLog ProjectsDrillingLog get; set;
public virtual ProjectsDutchCone ProjectsDutchCone get; set;
public virtual ProjectsGap ProjectsGap get; set;
//public virtual ProjectsLogDrafting ProjectsLogDrafting get; set;
public virtual ProjectsRole ProjectsRole get; set;
public virtual ProjectsUnc ProjectsUnc get; set;
public virtual ICollection<Boreholes> Boreholes get; set;
public virtual ICollection<ProjectsWorkAmount> ProjectsWorkAmounts get; set;
public virtual ICollection<Zones> Zones get; set;
我再次提到模型是由“脚手架”命令创建的。 CRUD 操作由 GenericRepository 处理：
using geotech_Tests_Model.Entities;
using geotech_Tests_Model.Interfaces;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Query.Internal;
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
namespace myProj_Model.Repositories
public class GenericRepository<T> : IGenericRepository<T> where T : class
protected geotechContext _context get; set;
public GenericRepository(geotechContext context)
this._context = context;
public void Add(T entity)
try
_context.Set<T>().Add(entity);
_context.SaveChanges();
catch (Exception eXp)
string Myname = eXp.Message;
public void AddRange(IEnumerable<T> entities)
try
_context.Set<T>().AddRange(entities);
_context.SaveChanges();
catch (Exception eXp)
string Myname = eXp.Message;
public void Update(T entity)
try
_context.Set<T>().Update(entity);
_context.SaveChanges();
catch (Exception eXp)
string Myname = eXp.Message;
public void UpdateRange(IEnumerable<T> entities)
try
_context.Set<T>().UpdateRange(entities);
_context.SaveChanges();
catch (Exception eXp)
string Myname = eXp.Message;
public IQueryable<T> Find()
return _context.Set<T>().AsQueryable();
public List<T> Find(FilterStruct filterstruct)
Expression<Func<T, bool>> myExpresion = Expresion(filterstruct);
return _context.Set<T>().AsQueryable().IgnoreAutoIncludes().Where(myExpresion).ToList ();
public T GetById(long id)
return _context.Set<T>().Find(id);
public void Remove(T entity)
try
_context.Set<T>().Remove(entity);
_context.SaveChanges();
catch (Exception eXp)
string Myname = eXp.Message;
public void RemoveRange(IEnumerable<T> entities)
try
_context.Set<T>().RemoveRange(entities);
_context.SaveChanges();
catch (Exception eXp)
string Myname = eXp.Message;
public Expression< Func<T, bool>> Expresion(FilterStruct filters)
//IQueryable<T> myQry = _context.Set<T>().AsQueryable<T>();
//IQueryable<T> myQryFilter = _context.Set<T>().AsQueryable<T>();
List<QueryStruct> queries = filters.Queries;
Expression predicateBody = null;
ParameterExpression myExp = Expression.Parameter(typeof(T), typeof(T).Name);
if (queries != null)
foreach (QueryStruct query in queries)
Expression e1 = null;
Expression left = Expression.Property(myExp, typeof(T).GetProperty(query.columnName));
Type actualType = Type.GetType(left.Type.FullName);
var myValue = Convert.ChangeType(query.value, actualType);
Expression right = Expression.Constant(myValue);
e1 = ApplyOperand(left, right, query.operatorName);
if (predicateBody == null)
predicateBody = e1;
else
predicateBody = ApplyAndOr(predicateBody, e1, query.AndOr);
//var p = Expression.Parameter(typeof(T), typeof(T).Name);
//if (predicateBody == null) predicateBody = Expression.Constant(true);
//MethodCallExpression whereCallExpression = Expression.Call(
//typeof(Queryable),
//"Where", new Type[] myQryFilter.ElementType ,
//myQryFilter.Expression, Expression.Lambda<Func<T>, bool> > (predicateBody, myExp));
var Lambda = Expression.Lambda <Func<T, bool>>(predicateBody, myExp);
return Lambda;
public static Expression ApplyOperand(Expression Left, Expression Rigth, OperandEnum Operand)
Expression result = null;
switch (Operand)
case (OperandEnum.Equal):
result = Expression.Equal(Left, Rigth);
break;
case (OperandEnum.NotEqual):
result = Expression.NotEqual(Left, Rigth);
break;
case (OperandEnum.GreaterThan):
result = Expression.GreaterThan(Left, Rigth);
break;
case (OperandEnum.GreaterThanOrEqual):
result = Expression.GreaterThanOrEqual(Left, Rigth);
break;
case (OperandEnum.LessThan):
result = Expression.LessThan(Left, Rigth);
break;
case (OperandEnum.LessThanOrEqual):
result = Expression.LessThanOrEqual(Left, Rigth);
break;
return result;
public static Expression ApplyAndOr(Expression Left, Expression Rigth, AndOrEnum AndOr)
Expression result = null;
switch (AndOr)
case (AndOrEnum.And):
result = Expression.And(Left, Rigth);
break;
case (AndOrEnum.AndAlso):
result = Expression.AndAlso(Left, Rigth);
break;
case (AndOrEnum.AndAssign):
result = Expression.AndAssign(Left, Rigth);
break;
case (AndOrEnum.Or):
result = Expression.Or(Left, Rigth);
break;
case (AndOrEnum.OrAssign):
result = Expression.OrAssign(Left, Rigth);
break;
case (AndOrEnum.OrElse):
result = Expression.OrElse(Left, Rigth);
break;
return result;
我的 Startup.cs 中有这样的 ConfigureServices：
public void ConfigureServices(IServiceCollection services)
services.AddCors(options =>
options.AddPolicy(_appCorsPolicy,
builder =>
builder.WithOrigins("http://127.0.0.1:23243")
.AllowAnyHeader();
//.AllowAnyMethod();
);
);
//****************************************************************************************
services.AddControllers();
services.AddControllersWithViews().AddNewtonsoftJson(options => options.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore);
services.Configure<IISOptions>(options =>
);
services.AddAutoMapper(typeof(Startup));
// Register the Swagger generator, defining 1 or more Swagger documents
services.AddSwaggerGen(c =>
c.SwaggerDoc("v1", new OpenApiInfo Title = "Organization, .Net Core", Version = "V 01" );
// Set the comments path for the Swagger JSON and UI.
var xmlFile = $"Assembly.GetExecutingAssembly().GetName().Name.xml";
var xmlPath = Path.Combine(AppContext.BaseDirectory, xmlFile);
c.IncludeXmlComments(xmlPath);
);
string connectionStr = Configuration.GetConnectionString("DefaultConnection");
services.AddDbContext<geotechContext>(options => options.UseLazyLoadingProxies().UseSqlServer(connectionStr));
//Farzin
services.Add(new ServiceDescriptor(typeof(IProjectsService), typeof(ProjectsService), ServiceLifetime.Scoped));
// AddServicesHere
之后，我的项目实体有了一个服务类。 GetById 是我在 Service 类中拥有的几个函数之一。
public EventResult GetById(long id)
EventResult result = new EventResult();
//result.Data = service.GetById (id);
result.Data = service.Find().IgnoreAutoIncludes().Where(a => (a.Id == id)).FirstOrDefault();
return result;
现在的主要问题是，响应时间相当长。我跟踪每一行代码，甚至是执行的 sql 命令。 Sql profiler 显示发送到 SqlServer 的 sql 命令。命令是：
exec sp_executesql N'SELECT TOP(1) [g].[Id], [g].[gtp_ClientName], [g].[CreatedBy], [g].[CreatedDate], [g].[gtP_Description], [g].[gtp_Logo], [g].[gtp_LogoHeight], [g].[gtp_LogoWidth], [g].[ModifiedBy], [g].[ModifiedDate], [g].[gtP_Name], [g].[gtp_NoOfRecord], [g].[gtP_ProjectNumber], [g].[gtp_Revision], [g].[gtp_Version], [g].[gtp_WorkValueIsLimit]
FROM [gt_Projects] AS [g]
WHERE [g].[Id] = @__id_0',N'@__id_0 bigint',@__id_0=1
没有任何关系，这个sql的执行结果是一个简单的行，没有任何额外的数据。但我大摇大摆地得到的答案是包含所有相关数据的复杂记录。
Result of query
我希望招摇的结果是这样的
Expected Result
但结果是这样的：
"errorNumber": 0,
"errorMessage": "",
"eventId": 0,
"data":
"createdBy_User":
"projectsRoleId1": null,
"boreholeCreatedByNavigations": [],
"boreholeModifiedByNavigations": [],
"boreholeTypeCreatedByNavigations": [
"boreholes": [],
"id": 1,
"abbriviation": "P",
"name": "Primary",
"description": "Primary Boreholes",
"order": 1,
"color": null,
"createdBy": 1,
"createdDate": "1400-05-27T00:00:00",
"modifiedBy": 1,
"modifiedDate": "1400-05-27T00:00:00"
],
"boreholeTypeModifiedByNavigations": [
"boreholes": [],
"id": 1,
"abbriviation": "P",
"name": "Primary",
"description": "Primary Boreholes",
"order": 1,
"color": null,
"createdBy": 1,
"createdDate": "1400-05-27T00:00:00",
"modifiedBy": 1,
"modifiedDate": "1400-05-27T00:00:00"
],
"boreholesWorkAmountCreatedByNavigations": [],
"boreholesWorkAmountModifiedByNavigations": [],
"dailyActivityDaCoSupervisorNavigations": [],
"dailyActivityDaSpecialistNavigations": [],
"dailyActivityDaSupervisorNavigations": [],
"dailyActivityDaTechnision01Navigations": [],
"dailyActivityDaTechnision02Navigations": [],
"created_Projects": [
"projectsDrillingLog": null,
"projectsDutchCone": null,
"projectsGap": null,
"projectsRole": null,
"projectsUnc": null,
"boreholes": [],
"projectsWorkAmounts": [],
"zones": [],
"id": 2,
"number": "001",
"name": "Yes",
"description": "ss",
"clientName": "ss",
"noOfRecord": 1,
"logo": null,
.........
.........
"id": 5,
"workActivity": 6,
"project": 1,
"activityPredicted": 5,
"activityActual": null,
"startDatePredicted": null,
"endDatePredicted": null,
"startDateActual": null,
"endDateActual": null,
"createdBy": null,
"createdDate": null,
"modifiedBy": null,
"modifiedDate": null
],
"zones": [],
"id": 1,
"number": "001",
"name": "No",
"description": "ss",
"clientName": "ss",
"noOfRecord": 1,
"logo": null,
"logoWidth": 11,
"logoHeight": 11,
"version": "1",
"revision": 1,
"workValueIsLimit": 1,
"createdBy": 1,
"createdDate": "1400-06-01T00:00:00",
"modifiedBy": 1,
"modifiedDate": "1400-06-01T00:00:00"
答案包含近 4700 行数据，这发生在我的数据库几乎是空的时候。 我不知道为什么以及我应该怎么做才能得到我的预期结果作为答案。
【问题讨论】：
你是对的。我从我的 Db 设置中删除了 .UseLazyLoadingProxies() ，现在一切正常。非常感谢。 【参考方案1】：我注意到你有.UseLazyLoadingProxies()，这意味着你可以从数据库中加载一些数据，然后通过访问属性触发加载更多数据；例如，您只下载了一个项目，但一旦您尝试访问其 Boreholes 集合，该访问将触发另一个查询，如 SELECT * FROM Boreholes WHERE projectId = (whatever the current project id is) 以在返回之前填充钻孔集合..
这意味着当序列化程序枚举您的起始Project 的属性时，寻找可以序列化的数据，而不是在访问某些相关数据的导航属性时获取“null”或“空”，它是序列化程序这会触发每个相关实体的数据库查找......然后它会序列化所有这些相关实体并枚举 它们的道具会触发更多查找。
一开始只是一个项目，然后滚雪球加载每个相关实体上下树，甚至可能是整个数据库，只是因为您要求序列化程序将项目对象转换为 json..
删除延迟加载代理功能将停止该功能，但项目的其他部分不会在访问时自动加载数据；您对此所做的可能是关于如何加载相关数据的更广泛的设计决策..
【讨论】：
我不需要自动加载数据。如果我需要项目数据的其他部分，那么我使用 Include。无论如何，我感谢你的帮助。非常感谢。 @FarzinSotoodi 那么你必须关闭你的延迟加载。那么你每次都会得到不必要的信息以上是关于Entityframework core where条件，执行的sql字符串及其结果的主要内容，如果未能解决你的问题，请参考以下文章
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