C# 如何连接 PostgreSQL 基础教程

1.准备

1.安装 PostgreSQL 数据库服务器
2.安装 Npgsql 驱动程序，每一个解决方案都要提前添加
3.C# 开发环境：Visual Studio

2.连接 PostgreSQL 的步骤

2.1：导入必要的命名空间

using Npgsql;

2.2：创建连接字符串

string connString = "Host = localhost;Port = 5432;Username = postgres;Password = slac1028;Database = mydb;";

2.3：创建 PostgreSQL 连接对象

NpgsqlConnection conn = new NpgsqlConnection(connString);

2.4：打开数据库连接

conn.Open();

2.5：执行数据库操作

string sql = "INSERT INTO weathers VALUES('San Francisco',40,50,0.25,'1994-11-27');";
NpgsqlCommand cmd = new NpgsqlCommand(sql, conn);
cmd.ExecuteNonQuery();

2.6：关闭数据库连接

conn.Close();

示例：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Npgsql;

namespace pgsql_demo2
{
    class Program
    {
        static void Main(string[] args)
        {
            string connString = "Host = localhost;Port = 5432;Username = postgres;Password = slac1028;Database = mydb;";
            NpgsqlConnection conn = new NpgsqlConnection(connString);
            try
            {
                conn.Open();

                string sql = "INSERT INTO weathers VALUES('San Francisco',40,50,0.25,'1994-11-27');";
                NpgsqlCommand cmd = new NpgsqlCommand(sql, conn);
                //cmd.Parameters.AddWithValue("@temp_lo", 40);
                //cmd.Parameters.AddWithValue("@temp_hi", 50);
                //cmd.Parameters.AddWithValue("@prcp", 0.25);
                //cmd.Parameters.AddWithValue("@date", 1994 - 11 - 27);

                cmd.ExecuteNonQuery();
                
                Console.WriteLine(" 数据插入成功！");
                Console.ReadKey();

            }
            catch (Exception ex)
            {
                Console.WriteLine("发生错误：" + ex.Message);
            }
            finally 
            {
                conn.Close();
            }            
        }
    }
}