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Add EF Core 3.1 database seeding example.
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‎Examples/EFCoreSeedDb/.config/dotnet-tools.json‎

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{
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"version": 1,
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"isRoot": true,
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"tools": {
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"dotnet-ef": {
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"version": "3.1.7",
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"commands": [
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"dotnet-ef"
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]
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}
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}
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}

‎Examples/EFCoreSeedDb/EFCoreSeedDb.csproj‎

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<Project Sdk="Microsoft.NET.Sdk">
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<PropertyGroup>
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<OutputType>Exe</OutputType>
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<TargetFramework>netcoreapp3.1</TargetFramework>
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</PropertyGroup>
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<ItemGroup>
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<PackageReference Include="Bogus" Version="30.0.4" />
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<PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="3.1.7">
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<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
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<PrivateAssets>all</PrivateAssets>
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</PackageReference>
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<PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="3.1.7" />
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</ItemGroup>
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</Project>

‎Examples/EFCoreSeedDb/Program.cs‎

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using System;
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using System.Collections.Generic;
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using System.Linq;
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using Bogus;
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using Bogus.Extensions;
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using Microsoft.EntityFrameworkCore;
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using static System.Console;
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namespace EFCoreSeedDb
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{
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class Program
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{
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static void Main(string[] args)
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{
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WriteLine("Bogus Blog Example!");
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using var ctx = new BloggingContext();
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var blogs = ctx.Blogs
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.Include(b => b.Posts)
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.ToList();
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foreach( var blog in blogs)
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{
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WriteLine($"Blog Id: {blog.BlogId}");
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WriteLine($"Blog Url: {blog.Url}");
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foreach( var post in blog.Posts )
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{
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WriteLine($" Post Id: {post.PostId}");
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WriteLine($" Title: {post.Title}");
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WriteLine($" Content: {post.Content}");
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}
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WriteLine();
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WriteLine();
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}
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}
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}
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public class BloggingContext : DbContext
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{
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public DbSet<Blog> Blogs { get; set; }
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public DbSet<Post> Posts { get; set; }
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protected override void OnConfiguring(DbContextOptionsBuilder options)
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{
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options.UseSqlite("Data Source=blogging.db");
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options.EnableSensitiveDataLogging();
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}
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protected override void OnModelCreating(ModelBuilder modelBuilder)
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{
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base.OnModelCreating(modelBuilder);
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FakeData.Init(10);
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modelBuilder.Entity<Blog>().HasData(FakeData.Blogs);
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modelBuilder.Entity<Post>().HasData(FakeData.Posts);
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}
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}
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/// <summary>
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/// Example uses Faker[T]
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/// </summary>
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public static class FakeData
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{
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public static Faker<Blog> BlogFaker;
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public static Faker<Post> PostFaker;
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public static List<Blog> Blogs = new List<Blog>();
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public static List<Post> Posts = new List<Post>();
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public static void Init(int count)
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{
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var postId = 1;
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PostFaker = new Faker<Post>()
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.RuleFor(p => p.PostId, _ => postId++)
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.RuleFor(p => p.Title, f => f.Hacker.Phrase())
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.RuleFor(p => p.Content, f => f.Lorem.Sentence());
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var blogId = 1;
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BlogFaker = new Faker<Blog>()
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.RuleFor(b => b.BlogId, _ => blogId++)
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.RuleFor(b => b.Url, f => f.Internet.Url())
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.RuleFor(b => b.Posts, (f, b) =>
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{
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var posts = PostFaker.GenerateBetween(3, 5);
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FakeData.Posts.AddRange(posts);
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foreach( var post in posts )
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{
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post.BlogId = b.BlogId;
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}
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return null; // Blog.Posts is a getter only. The return value has no impact.
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});
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Blogs = BlogFaker.Generate(count);
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}
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}
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/// <summary>
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/// Example uses Faker facade
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/// </summary>
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public static class FakeData2
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{
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public static int BlogId = 1;
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public static List<Blog> Blogs = new List<Blog>();
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public static int PostId = 1;
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public static List<Post> Posts = new List<Post>();
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private static Faker f;
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public static void Init(int count)
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{
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f = new Faker();
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GenerateBlogs(count);
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}
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private static void GenerateBlogs(int blogCount)
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{
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for( var i = 0; i < blogCount; i++, BlogId++ )
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{
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var blog = new Blog
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{
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BlogId = BlogId,
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Url = f.Internet.Url()
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};
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Blogs.Add(blog);
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var postCount = f.Random.Number(3, 5);
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GeneratePost(blog, postCount);
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};
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}
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private static void GeneratePost(Blog b, int postCount)
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{
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for( var i = 0; i < postCount; i++, PostId++ )
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{
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var post = new Post
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{
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PostId = PostId,
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BlogId = b.BlogId,
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Title = f.Hacker.Phrase(),
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Content = f.Lorem.Sentence()
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};
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Posts.Add(post);
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}
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}
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}
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public class Blog
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{
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public int BlogId { get; set; }
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public string Url { get; set; }
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public List<Post> Posts { get; } = new List<Post>();
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}
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public class Post
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{
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public int PostId { get; set; }
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public string Title { get; set; }
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public string Content { get; set; }
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public int BlogId { get; set; }
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public Blog Blog { get; set; }
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}
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}

‎Examples/EFCoreSeedDb/README.md‎

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[1]:https://docs.microsoft.com/en-us/ef/core/get-started/
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[2]:https://docs.microsoft.com/en-us/ef/core/modeling/data-seeding
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## EF Core Seed Database Example with Bogus
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#### Requirements
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* **.NET Core 3.1** or later
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* **EF Core 3.1** or later
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#### Description
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The `EFCoreSeedDb` example is based on the [**EF Core Tutorial**][1] with the [**HasData**][2] method using **Bogus**.
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To run the example, perform the following commands *inside* this `EfCoreSeedDb` folder:
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* `dotnet restore`
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* `dotnet build`
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* `dotnet ef migrations add InitialCreate`
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* `dotnet ef database update`
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* `dotnet run`
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After the `dotnet` commands are executed above, you should have a `blogging.db` SQLite DB file that you can open and inspect the sample data generated from Bogus. Additionally, the `dotnet run` command will print out the data generated by Bogus to the console read from the `blogging.db` SQLite DB file.
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The basic approach is to pre-generate your Bogus data in-memory, in static properties, before sending sample data to EF Core.
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* `FakeData` - Uses the `Faker<T>` approach.
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* `FakeData2` - Uses the `Faker` facade approach.
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Either approach above can be used; pick whichever fits your preference and coding style.

‎Examples/Examples.sln‎

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Microsoft Visual Studio Solution File, Format Version 12.00
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# Visual Studio Version 16
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VisualStudioVersion = 16.0.29613.14
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MinimumVisualStudioVersion = 16.0.29613.14
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Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "EFCoreSeedDb", "EFCoreSeedDb\EFCoreSeedDb.csproj", "{7B012C90-4B93-4DB8-A0BA-AA91460DE392}"
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EndProject
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Global
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GlobalSection(SolutionConfigurationPlatforms) = preSolution
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Debug|Any CPU = Debug|Any CPU
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Debug|x64 = Debug|x64
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Debug|x86 = Debug|x86
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Release|Any CPU = Release|Any CPU
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Release|x64 = Release|x64
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Release|x86 = Release|x86
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EndGlobalSection
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GlobalSection(SolutionProperties) = preSolution
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HideSolutionNode = FALSE
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EndGlobalSection
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GlobalSection(ProjectConfigurationPlatforms) = postSolution
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{7B012C90-4B93-4DB8-A0BA-AA91460DE392}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
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{7B012C90-4B93-4DB8-A0BA-AA91460DE392}.Debug|Any CPU.Build.0 = Debug|Any CPU
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{7B012C90-4B93-4DB8-A0BA-AA91460DE392}.Debug|x64.ActiveCfg = Debug|Any CPU
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{7B012C90-4B93-4DB8-A0BA-AA91460DE392}.Debug|x64.Build.0 = Debug|Any CPU
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{7B012C90-4B93-4DB8-A0BA-AA91460DE392}.Debug|x86.ActiveCfg = Debug|Any CPU
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{7B012C90-4B93-4DB8-A0BA-AA91460DE392}.Debug|x86.Build.0 = Debug|Any CPU
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{7B012C90-4B93-4DB8-A0BA-AA91460DE392}.Release|Any CPU.ActiveCfg = Release|Any CPU
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{7B012C90-4B93-4DB8-A0BA-AA91460DE392}.Release|Any CPU.Build.0 = Release|Any CPU
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{7B012C90-4B93-4DB8-A0BA-AA91460DE392}.Release|x64.ActiveCfg = Release|Any CPU
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{7B012C90-4B93-4DB8-A0BA-AA91460DE392}.Release|x64.Build.0 = Release|Any CPU
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{7B012C90-4B93-4DB8-A0BA-AA91460DE392}.Release|x86.ActiveCfg = Release|Any CPU
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{7B012C90-4B93-4DB8-A0BA-AA91460DE392}.Release|x86.Build.0 = Release|Any CPU
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EndGlobalSection
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EndGlobal

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