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seed 数据库 dotnet

发布时间 2024-01-07 21:32:24作者: 虎虎生威啊

如何使用数据库

创建DataContext.cs

using Microsoft.EntityFrameworkCore;
using PokemonReviewApp.Models;

namespace PokemonReviewApp.Data
{
    public class DataContext : DbContext
    {
        public DataContext(DbContextOptions<DataContext> options) : base(options)
        {

        }

        public DbSet<Category> Categories { get; set; }
        public DbSet<Country> Countries { get; set; }
        public DbSet<Owner> Owners { get; set; }
        public DbSet<Pokemon> Pokemon { get; set; }
        public DbSet<PokemonOwner> PokemonOwners { get; set; }
        public DbSet<PokemonCategory> PokemonCategories { get; set; }
        public DbSet<Review> Reviews { get; set; }
        public DbSet<Reviewer> Reviewers { get; set; }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<PokemonCategory>()
                    .HasKey(pc => new { pc.PokemonId, pc.CategoryId });
            // ..........................
        }
    }
}

Program.cs注册服务

using Microsoft.EntityFrameworkCore;

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddDbContext<DataContext>(options =>
{
    options.UseSqlite(builder.Configuration.GetConnectionString("DefaultConnection"));
});

Seed数据库

编写seed.cs

using PokemonReviewApp.Data;
using PokemonReviewApp.Models;

namespace PokemonReviewApp
{
    public class Seed
    {
        private readonly DataContext dataContext;
        public Seed(DataContext context)
        {
            this.dataContext = context;
        }
        public void SeedDataContext()
        {
            if (!dataContext.PokemonOwners.Any())
            {
                var pokemonOwners = new List<PokemonOwner>()
                {
                    new PokemonOwner()
                    {

                        Pokemon = new Pokemon()
                        {
                            Name = "Pikachu",
                            BirthDate = new DateTime(1903,1,1),
                            PokemonCategories = new List<PokemonCategory>()
                            {
                                new PokemonCategory { Category = new Category() { Name = "Electric"}}
                            },
                            Reviews = new List<Review>()
                            {
                                new Review { Title="Pikachu",Text = "Pickahu is the best pokemon, because it is electric", Rating = 5,
                                Reviewer = new Reviewer(){ FirstName = "Teddy", LastName = "Smith" } },
                                new Review { Title="Pikachu", Text = "Pickachu is the best a killing rocks", Rating = 5,
                                Reviewer = new Reviewer(){ FirstName = "Taylor", LastName = "Jones" } },
                                new Review { Title="Pikachu",Text = "Pickchu, pickachu, pikachu", Rating = 1,
                                Reviewer = new Reviewer(){ FirstName = "Jessica", LastName = "McGregor" } },
                            }
                        },
                        Owner = new Owner()
                        {
                            FirstName = "Jack",
                            LastName = "London",
                            Gym = "Brocks Gym",
                            Country = new Country()
                            {
                                Name = "Kanto"
                            }
                        }
                    },
                    new PokemonOwner()
                    {
                        Pokemon = new Pokemon()
                        {
                            Name = "Squirtle",
                            BirthDate = new DateTime(1903,1,1),
                            PokemonCategories = new List<PokemonCategory>()
                            {
                                new PokemonCategory { Category = new Category() { Name = "Water"}}
                            },
                            Reviews = new List<Review>()
                            {
                                new Review { Title= "Squirtle", Text = "squirtle is the best pokemon, because it is electric", Rating = 5,
                                Reviewer = new Reviewer(){ FirstName = "Teddy", LastName = "Smith" } },
                                new Review { Title= "Squirtle",Text = "Squirtle is the best a killing rocks", Rating = 5,
                                Reviewer = new Reviewer(){ FirstName = "Taylor", LastName = "Jones" } },
                                new Review { Title= "Squirtle", Text = "squirtle, squirtle, squirtle", Rating = 1,
                                Reviewer = new Reviewer(){ FirstName = "Jessica", LastName = "McGregor" } },
                            }
                        },
                        Owner = new Owner()
                        {
                            FirstName = "Harry",
                            LastName = "Potter",
                            Gym = "Mistys Gym",
                            Country = new Country()
                            {
                                Name = "Saffron City"
                            }
                        }
                    },
                    new PokemonOwner()
                    {
                        Pokemon = new Pokemon()
                        {
                            Name = "Venasuar",
                            BirthDate = new DateTime(1903,1,1),
                            PokemonCategories = new List<PokemonCategory>()
                            {
                                new PokemonCategory { Category = new Category() { Name = "Leaf"}}
                            },
                            Reviews = new List<Review>()
                            {
                                new Review { Title="Veasaur",Text = "Venasuar is the best pokemon, because it is electric", Rating = 5,
                                Reviewer = new Reviewer(){ FirstName = "Teddy", LastName = "Smith" } },
                                new Review { Title="Veasaur",Text = "Venasuar is the best a killing rocks", Rating = 5,
                                Reviewer = new Reviewer(){ FirstName = "Taylor", LastName = "Jones" } },
                                new Review { Title="Veasaur",Text = "Venasuar, Venasuar, Venasuar", Rating = 1,
                                Reviewer = new Reviewer(){ FirstName = "Jessica", LastName = "McGregor" } },
                            }
                        },
                        Owner = new Owner()
                        {
                            FirstName = "Ash",
                            LastName = "Ketchum",
                            Gym = "Ashs Gym",
                            Country = new Country()
                            {
                                Name = "Millet Town"
                            }
                        }
                    }
                };
                dataContext.PokemonOwners.AddRange(pokemonOwners);
                dataContext.SaveChanges();
            }
        }
    }
}

注册seed服务


using Microsoft.EntityFrameworkCore;
var builder = WebApplication.CreateBuilder(args);


builder.Services.AddTransient<Seed>();

var app = builder.Build();

if (args.Length == 1 && args[0].ToLower() == "seeddata")
    SeedData(app);

void SeedData(IHost app)
{
    var scopedFactory = app.Services.GetService<IServiceScopeFactory>();

    using (var scope = scopedFactory.CreateScope())
    {
        // Summary:
        //     Get service of type T from the System.IServiceProvider.
        // Parameters:
        //   provider:
        //     The System.IServiceProvider to retrieve the service object from.
        // Type parameters:
        //   T:
        //     The type of service object to get.
        // Returns:
        //     A service object of type T or null if there is no such service.
        var service = scope.ServiceProvider.GetService<Seed>();
        service.SeedDataContext();
    }
}

app.Run();