添加EFCoreTest项目

Former-commit-id: 1c394a4d4b42a2f7aac54cd74d87840e2b913b5b

labs/EFCoreTest/.gitignore

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+*.bak
+*.suo
+*.db
+*.db-shm
+*.db-wal
+*.user
+.vs
+obj
+Obj
+bin
+Bin
+debug
+Debug
+release
+Release
+Logs
+logs
+node_modules

labs/EFCoreTest/EFCoreTest.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="3.1.2" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="3.1.2" />
+    <PackageReference Include="Pomelo.EntityFrameworkCore.MySql" Version="3.1.1" />
+  </ItemGroup>
+
+</Project>

labs/EFCoreTest/EFCoreTest.sln

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+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 16
+VisualStudioVersion = 16.0.29814.53
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "EFCoreTest", "EFCoreTest.csproj", "{4BB784D0-B6BB-4450-9E34-F64EA74B5555}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{4BB784D0-B6BB-4450-9E34-F64EA74B5555}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{4BB784D0-B6BB-4450-9E34-F64EA74B5555}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{4BB784D0-B6BB-4450-9E34-F64EA74B5555}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{4BB784D0-B6BB-4450-9E34-F64EA74B5555}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {C2F655E3-914B-48C5-A6C5-7674A05F5CFD}
+	EndGlobalSection
+EndGlobal

labs/EFCoreTest/Program.cs

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+using Microsoft.EntityFrameworkCore;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace EFCoreTest
+{
+    public class MyDbContext : DbContext
+    {
+        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
+        {
+            optionsBuilder.UseSqlite("Data Source=data.db;");
+            //optionsBuilder.UseMySql("Server=139.180.143.95;Port=3306;Database=test;Uid=admin;Pwd=admin;");
+        }
+
+        protected override void OnModelCreating(ModelBuilder modelBuilder)
+        {
+            modelBuilder.Entity<User>();
+            modelBuilder.Entity<Role>();
+            modelBuilder.Entity<UserRole>().HasOne(o => o.User).WithMany(o => o.UserRoles).HasForeignKey(o => o.UserId);
+            modelBuilder.Entity<UserRole>().HasOne(o => o.Role).WithMany(o => o.UserRoles).HasForeignKey(o => o.RoleId);
+            modelBuilder.Entity<UserRole>().HasIndex(o => new { o.UserId, o.RoleId }).IsUnique();
+        }
+    }
+
+    public class Entity
+    {
+        public Guid Id { get; set; }
+
+        public Entity()
+        {
+            this.Id = Guid.NewGuid();
+        }
+    }
+
+    public class User : Entity
+    {
+        public string UserName { get; set; }
+        public List<UserRole> UserRoles { get; set; } = new List<UserRole>();
+    }
+
+    public class Role : Entity
+    {
+        public string Name { get; set; }
+        public List<UserRole> UserRoles { get; set; } = new List<UserRole>();
+    }
+
+    public class UserRole : Entity
+    {
+        public Guid UserId { get; set; }
+        public Guid RoleId { get; set; }
+        public User User { get; set; }
+        public Role Role { get; set; }
+    }
+
+    class Program
+    {
+        static void Main(string[] args)
+        {
+            using (var db = new MyDbContext())
+            {
+                if (db.Database.EnsureCreated())
+                {
+                    db.Set<User>().Add(new User { UserName = "test" });
+                    db.SaveChanges();
+                }
+                Console.WriteLine(db.Set<User>().FirstOrDefault()?.UserName);
+            }
+        }
+    }
+}