C#连接SQL server数据库命令的基本步骤

string connectionString = "Data Source=服务器名;Initial Catalog=数据库名;Integrated Security=True";

string connectionString = "Data Source=服务器名;Initial Catalog=数据库名;User ID=用户名;Password=密码";

using System;
using System.Data.SqlClient;
​
class Program
{
    static void Main()
    {
        // 定义连接字符串
        string connectionString = "Data Source=localhost;Initial Catalog=Northwind;Integrated Security=True";
​
        try
        {
            // 创建并打开数据库连接
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                connection.Open();
                Console.WriteLine("数据库连接成功！");
​
                // 定义SQL查询命令
                string sql = "SELECT CustomerID, CompanyName FROM Customers";
​
                // 创建SqlCommand对象
                using (SqlCommand command = new SqlCommand(sql, connection))
                {
                    // 执行查询并获取数据读取器
                    using (SqlDataReader reader = command.ExecuteReader())
                    {
                        // 读取查询结果
                        while (reader.Read())
                        {
                            Console.WriteLine($"客户ID: {reader["CustomerID"]}, 公司名称: {reader["CompanyName"]}");
                        }
                    }
​
                    // 执行插入命令示例
                    string insertSql = "INSERT INTO Products (ProductName, UnitPrice) VALUES (@ProductName, @UnitPrice)";
                    using (SqlCommand insertCommand = new SqlCommand(insertSql, connection))
                    {
                        // 添加参数以防止SQL注入
                        insertCommand.Parameters.AddWithValue("@ProductName", "新产品");
                        insertCommand.Parameters.AddWithValue("@UnitPrice", 9.99);
​
                        // 执行非查询命令（如INSERT、UPDATE、DELETE）
                        int rowsAffected = insertCommand.ExecuteNonQuery();
                        Console.WriteLine($"插入了{rowsAffected}行数据。");
                    }
                }
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine("数据库操作出错: " + ex.Message);
        }
    }
}