.net查询

using System;
using System.Data.SqlClient;

class Program
{
    static void Main()
    {
        string connectionString = "Server=myServerAddress;Database=myDataBase;User Id=myUsername;Password=myPassword;";
        
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            connection.Open();
            
            string sql = "SELECT * FROM Customers";
            SqlCommand command = new SqlCommand(sql, connection);
            
            using (SqlDataReader reader = command.ExecuteReader())
            {
                while (reader.Read())
                {
                    Console.WriteLine(reader["CustomerName"].ToString());
                }
            }
        }
    }
}

using System;
using System.Linq;
using Microsoft.EntityFrameworkCore;

public class Customer
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public class MyDbContext : DbContext
{
    public DbSet<Customer> Customers { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer("Server=myServerAddress;Database=myDataBase;User Id=myUsername;Password=myPassword;");
    }
}

class Program
{
    static void Main()
    {
        using (MyDbContext context = new MyDbContext())
        {
            var customers = context.Customers.ToList();
            foreach (var customer in customers)
            {
                Console.WriteLine(customer.Name);
            }
        }
    }
}