.Net 性能优化--EFCore(EntityFrameworkCore)
新建.NET CORE CONSOLE控制台项目NetCoreConsole，管理NuGet程序包种添加一下引用
//Microsoft.EntityFrameworkCore //EFCore
//Microsoft.Extensions.Logging // 日志
//Microsoft.Extensions.Logging.Console // 日志输出到Console控制台
//Microsoft.Extensions.Logging.Debug // 日志输出到调试Debug
//Microsoft.EntityFrameworkCore.Proxies// 懒加载，延迟加载，EFCore没有懒加载，使用该库，可以实现懒加载
//Microsoft.EntityFrameworkCore.SqlServer//EFCore使用的SqlServer数据库
//Pomelo.EntityFrameworkCore.MySql//EFCore使用的MySql数据库
项目代码如下：
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using Microsoft.Extensions.Logging;
using System.Linq;
using System.Diagnostics;
using Microsoft.EntityFrameworkCore.Storage;
//Microsoft.EntityFrameworkCore //EFCore
//Microsoft.Extensions.Logging // 日志
//Microsoft.Extensions.Logging.Console // 日志输出到Console控制台
//Microsoft.Extensions.Logging.Debug // 日志输出到调试Debug
//Microsoft.EntityFrameworkCore.Proxies// 懒加载，延迟加载，EFCore没有懒加载，使用该库，可以实现懒加载
//Microsoft.EntityFrameworkCore.SqlServer//EFCore使用的SqlServer数据库
//Pomelo.EntityFrameworkCore.MySql//EFCore使用的MySql数据库
namespace NetCoreConsole
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("测试 EF core ");
BlogContext blogContext = new BlogContext();
#region ef 数据库的创建和删除
//Console.WriteLine("删除数据库");
//blogContext.Database.EnsureDeleted();
//Console.WriteLine("添加数据库");
blogContext.Database.EnsureCreated();
//Console.WriteLine("添加数据库成功");
#endregion
#region 数据迁移相关
//IEnumerable vs = blogContext.Database.GetMigrations();
//blogContext.Database.GetPendingMigrations();
//blogContext.Database.GetAppliedMigrations();
//blogContext.Database.Migrate();
//Console.WriteLine("添加数据库成功");
#endregion
#region 预先加载，懒加载
//预先加载(贪婪加载，饥饿加载，一次行加载所有)
//var list = blogContext.Blog.Include(op => op.Posts).ThenInclude(op => op.Author).ToList();
//var list = blogContext.Blog.Include(op => op.Posts).ThenInclude(op => op.Author).ToList();
//var list = blogContext.Blog.Include(op => op.Posts).ThenInclude(op => op.Author).ToList().AsQueryable();
//foreach (var item in list)
//{
// Console.WriteLine($"blog:{item}");
// foreach (var it in item.Posts)
// {
// Console.WriteLine($"Posts:{it.Title}");
// Console.WriteLine($"person:{it.Author.Name}");
// }
//}
//懒加载(延迟加载)，又称按需加载，net ef core 默认时候没有懒加载的，
//ef是有的，ef core 要使用懒加载，需要使用proxy代理类UseLazyLoadingProxies，并且导航属性要添加Virtual标记
//optionsBuilder.UseLazyLoadingProxies()
#endregion
#region IQueryable和IEnumerable不同
//IQueryable和IEnumerable不同
//IQueryable和IEnumerable都是linq操作
//IQueryable和IEnumerable都是延迟执行，tolist的时候在执行
//只不过操作的位置不同，IQueryable是在数据库一侧操作，而IEnumerable实在应用程序的内存一侧操作，
//IQueryable继承IEnumerable，IQueryable与IEnumerable 可以相互转换，IQueryable.AsIEnumerable,IEnumerable.AsIQueryable
//var item = blogContext.Post.OrderBy(op => EF.Property
//IQueryable 在数据库中的 执行脚本，IQueryable和IEnumerable都是延迟执行，tolist的时候在执行
//exec sp_executesql N‘SELECT [p].[PostId], [p].[BlogId], [p].[Content], [p].[PersonId], [p].[Title]
//FROM[Post] AS[p]
//ORDER BY[p].[Title]
//OFFSET @__p_0 ROWS FETCH NEXT @__p_1 ROWS ONLY‘,N‘@__p_0 int,@__p_1 int‘,@__p_0=1,@__p_1=2
//foreach (var it in item)
//{
// Console.WriteLine($"it:{it.Title}");
//}
//var item = blogContext.Post.OrderBy(op => op.Title).AsEnumerable().Skip(1).Take(2);
//IEnumerable在内存中的 执行脚本，IQueryable和IEnumerable都是延迟执行，tolist的时候在执行
//SELECT[p].[PostId], [p].[BlogId], [p].[Content], [p].[PersonId], [p].[Title]
//FROM[Post] AS[p]
//ORDER BY[p].[Title]
//foreach (var it in item)
//{
// Console.WriteLine($"it:{it.Title}");
//}
#endregion
#region 实体跟踪Tracking
//一种是全局修改之后在修改回来
//另外一种是，是使用AsNoTracking()直接修改
//blogContext.ChangeTracker.QueryTrackingBehavior = QueryTrackingBehavior.NoTracking;
using (IDbContextTransaction transaction = blogContext.Database.BeginTransaction())
{
//var item = blogContext.Post.Where(op => op.Title.Contains("10"));
var item = blogContext.Post.AsNoTracking().Where(op => op.Title.Contains("10"));
//foreach (var it in item)
// {
// Console.WriteLine($"it:{it.Title}");
// it.Title = "111";
// }
// blogContext.SaveChanges();
transaction.Commit();
}
//blogContext.ChangeTracker.QueryTrackingBehavior = QueryTrackingBehavior.TrackAll;
#endregion
#region 模糊查询StartsWith,,EndsWith,Contains,其中Contains和 EF.Functions.Like功能一样，但是sql语句翻译的确实不一样的
但凡使用的计算函数，索引是一定不会被用上的
//var item = blogContext.Post.Where(op => op.Title.Contains("10")).ToList();
SELECT[p].[PostId], [p].[BlogId], [p].[Content], [p].[PersonId], [p].[Title]
FROM[Post] AS[p]
WHERE CHARINDEX(N‘10‘, [p].[Title]) > 0
//foreach (var it in item)
//{
// Console.WriteLine($"it:{it.Title}");
//}
//item = blogContext.Post.Where(op => EF.Functions.Like(op.Title, "%10%")).ToList();
SELECT[p].[PostId], [p].[BlogId], [p].[Content], [p].[PersonId], [p].[Title]
FROM[Post] AS[p]
WHERE[p].[Title]
LIKE N‘%10%‘
//foreach (var it in item)
//{
// Console.WriteLine($"it:{it.Title}");
//}
#endregion
#region 自定义标量函数，linq一样可以翻译成对应的sql脚本
SELECT[p].[PostId] AS[id], [dbo].[MyFunction] ([p].[PostId]) AS[name]
FROM[Post] AS[p]
//var item = blogContext.Post.Select(op => new
//{
// id = op.PostId,
// name = BlogContext.MyFunction(op.PostId)//使用标量函数
//}).ToList();
//foreach (var it in item)
//{
// Console.WriteLine($"it:{it.name}");
//}
#endregion
#region 编译查询
#region 普通查询
//int id = 1;
//Stopwatch stopwatch = new Stopwatch();
//stopwatch.Start();
//var item = blogContext.Post.Where(op => op.PostId == id).FirstOrDefault();
//stopwatch.Stop();
//Console.WriteLine($"普通查询：item:{item.Title},用时：{stopwatch.ElapsedMilliseconds}");
// exec sp_executesql N‘SELECT TOP(1) [p].[PostId], [p].[BlogId], [p].[Content], [p].[PersonId], [p].[Title]
//FROM[Post] AS[p]
//WHERE[p].[PostId] = @__id_0‘,N‘@__id_0 int‘,@__id_0=1
#endregion
#region 编译查询
//Stopwatch stopwatch = new Stopwatch();
//stopwatch.Start();
var compileQuery = EF.CompileQuery((BlogContext context, int id) => context.Post.Where(c => c.PostId == id).FirstOrDefault());
var item = compileQuery(blogContext, 1);
//stopwatch.Stop();
//Console.WriteLine($"普通查询：item:{item.Title},用时：{stopwatch.ElapsedMilliseconds}");
#endregion
//普通查询
Func<BlogContext, Blog> unCompileQuery = context => context.Blog.Include(c => c.Posts).Where(a => a.BlogId == 1).FirstOrDefault();
Stopwatch stopwatch = new Stopwatch();
stopwatch.Start();
Console.WriteLine("普通查询开始");
for (int i = 0; i < 100000; i++)
{
var a = unCompileQuery(blogContext);
}
stopwatch.Stop();
Console.WriteLine($"编译查询 用时：{stopwatch.ElapsedMilliseconds} 毫秒");
//编译查询 一般是大量数据查询，并且参数不变的情况下比较好，但是不能返回集合
//Stopwatch stopwatch = new Stopwatch();
//stopwatch.Start();
//Console.WriteLine("编译查询开始");
//var compileQuery = EF.CompileQuery((BlogContext context, int id) => context.Blog.Include(c => c.Posts).Where(a => a.BlogId == 1).FirstOrDefault());
//for (int i = 0; i < 100000; i++)
//{
// var item = compileQuery(blogContext, 1);
//}
//stopwatch.Stop();
//Console.WriteLine($"编译查询 用时：{stopwatch.ElapsedMilliseconds} 毫秒");
#endregion
//var item = blogContext.Post.Where(op => op.Title.Contains("10"));
//foreach (var it in item)
//{
// Console.WriteLine($"it:{it.Title}");
//}
//var item = blogContext.Post.Where(op => EF.Functions.Like(op.Title,"10"));
//foreach (var it in item)
//{
// Console.WriteLine($"it:{it.Title}");
//}
Console.Read();
}
}
public class BlogContext : DbContext
{
public DbSet<Blog> Blog { get; set; }
public DbSet<Post> Post { get; set; }
public static readonly ILoggerFactory loggerFactory = LoggerFactory.Create(builder => builder.AddConsole().AddDebug());
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
//optionsBuilder.UseLoggerFactory(loggerFactory);//添加把数据库操作的信息输出到指定的控制台
//optionsBuilder.UseLazyLoadingProxies().UseSqlServer(@"server=127.0.0.1;database=mynetcore;user=sa;password=sa123;");
//Microsoft.EntityFrameworkCore.SqlServer
optionsBuilder.UseSqlServer(@"server=127.0.0.1;database=mynetcore;user=sa;password=sa123;");
//Pomelo.EntityFrameworkCore.MySql
//optionsBuilder.UseMySql(@"server=127.0.0.1;database=mynetcore;user=root;password=123456;");
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
List<Post> posts = new List<Post>();
for (int i = 0; i < 20; i++)
{
posts.Add(new Post { PostId = i + 1, PersonId = i >= 10 ? 2 : 1, Title = $"文章标题:100{i}", Content = $"文章内容:{i}", BlogId = i >= 10 ? 2 : 1 });
}
Blog blogs = new Blog { BlogId = 1, Url = "http://www.baidu.com" };
Blog blogs1 = new Blog { BlogId = 2, Url = "http://www.tianmao.com" };
Person person = new Person { PersonId = 1, Name = "123" };
Person person1 = new Person { PersonId = 2, Name = "456" };
modelBuilder.Entity<Post>().HasData(posts);
modelBuilder.Entity<Blog>().HasData(blogs, blogs1);
modelBuilder.Entity<Person>().HasData(person, person1);
}
#region 自定义标量函数
[DbFunction]
public static string MyFunction(int id)
{
throw new NotImplementedException();
}
#endregion
}
public class Blog
{
public int BlogId { get; set; }
public string Url { get; set; }
public virtual List<Post> Posts { get; set; }
}
public class Post
{
public int PostId { get; set; }
public string Title { get; set; }
public string Content { get; set; }
public int BlogId { get; set; }
public virtual Blog Blog { get; set; }
public int PersonId { get; set; }
public virtual Person Author { get; set; }
}
public class Person
{
public int PersonId { get; set; }
public string Name { get; set; }
public virtual List<Post> Posts { get; set; }
}
}