使用 EF Core 处理Sqlite数据库

1.通过NuGet安装Microsoft.EntityFrameworkCore.Sqlite

在这里插入图片描述

2.编写生成数据库的实体类

因为EF Core是通过实体类来作为数据库的字段

public class User
{
    /// <summary>
    /// 主键 Id
    /// </summary>
    [Key]
    public int Id { get; set; }
    /// <summary>
    /// 数据库 Name
    /// </summary>
    [Column("Name")]
    public string Name { get; set; }
    /// <summary>
    /// 数据库 Sex
    /// </summary>
    [Column("Sex")]
    public string Sex { get; set; }
}

3.编写EF Core的实体类

public class AppDbContext : DbContext
{
    private readonly string _connection;
    //实体表，提供给外部crud使用，PersonInfos内部有DataContext 的实例
    public DbSet<User> User { get; set; }
    public AppDbContext()
    {
        //1、获取连接数据库的字符串
        _connection = ConfigurationManager.ConnectionStrings["SqliteEF6ConnectionStr"].ConnectionString;
    }
    //2、联接数据库
    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        base.OnConfiguring(optionsBuilder);
        optionsBuilder.UseSqlite(_connection);
    }
    //3、建立实体和数据库表格 一 一 映射。  
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<User>().ToTable("User").HasKey(b => b.Id);
    }
}

4.创建数据库语句及增删改查

/// <summary>
/// 创建数据库
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button1_Click(object sender, EventArgs e)
{
    AppDbContext dbContext = new AppDbContext();
    dbContext.Database.EnsureCreated();
}
/// <summary>
/// 增加数据
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button2_Click(object sender, EventArgs e)
{
    AppDbContext dbContext = new AppDbContext();
    User user = new User();
    user.Name = "Test";
    user.Id = 1;
    user.Sex = "男";
    dbContext.Add(user);
    User user2 = new User();
    user2.Name = "Test";
    user2.Id = 3;
    user2.Sex = "男";
    dbContext.Add(user2);
    dbContext.SaveChanges();
}
/// <summary>
/// 修改数据
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button3_Click(object sender, EventArgs e)
{
    AppDbContext dbContext = new AppDbContext();
    User? user = dbContext.User.Where(b => b.Id == 3).FirstOrDefault();
    user.Sex = "女";
    dbContext.SaveChanges();
}
/// <summary>
/// 删除数据
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button4_Click(object sender, EventArgs e)
{
    AppDbContext dbContext = new AppDbContext();
    User? user = dbContext.User.Where(b => b.Id == 3).FirstOrDefault();
    dbContext.Remove(user);
    dbContext.SaveChanges();
}
/// <summary>
/// 查询数据
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button5_Click(object sender, EventArgs e)
{
    AppDbContext dbContext = new AppDbContext();
    List<User> users = dbContext.User.ToList();
}