using System;

​

using System.Text.Json;

using Microsoft.EntityFrameworkCore;

using Microsoft.Data.Sqlite;

using System.Linq;

​

public class UserEntity

    {

        //1.why query will call the constructor?

        public UserEntity(string name, string password) {

            Id=Guid.NewGuid();

            Name = name;

            Salt = Guid.NewGuid().ToString();

            //2.why [Password] is different,what is the rule

            Password = Salt;

        }

        public Guid Id { get; set; }

        public string Name { get; set; }

        public string Password { get; set; }

        public string Salt { get; set; }

    }

public class MyDbContext:DbContext

{

    public MyDbContext(DbContextOptions<MyDbContext> options)

        : base(options)

    {

        Database.EnsureCreated();

    }

​

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)

    {

    }

​

    protected override void OnModelCreating(ModelBuilder modelBuilder)

    {

    }

    public DbSet<UserEntity> User { get; set; }

}

public class Program

{

    public static void Main()

    {

        //config database context by sqlite

        var connection = new SqliteConnection("DataSource=:memory:");

            connection.Open();

            var options = new DbContextOptionsBuilder<MyDbContext>()

                    .UseSqlite(connection)

                    .Options;

        using (var context = new MyDbContext(options))

        {

            var admin = new UserEntity("admin", "admin123");

            Console.WriteLine(JsonSerializer.Serialize(admin));

            context.User.Add(admin);

            context.SaveChanges();

        }   

        using (var context = new MyDbContext(options))

        {

            var user = context.User.FirstOrDefault();

            Console.WriteLine(user == null ? "" : JsonSerializer.Serialize(user));

        }   

    }

}