C#数据库连接

using System;

using System.Data.SqlClient;

namespace 数据库连接及使用
{
    class 连接
    {
        //创建连接对象
        private SqlConnection conn = null;
        //创建连接所需要的信息
        private string ConnStr = "server = .;database = BookShop;uid = sa;pwd = 123456";//我的数据库是用sa进行登录的，密码是123456
        //做一个打开设置
        public bool Openconnection()
        {
            if(conn == null)
            {
                conn = new SqlConnection(ConnStr);
            }
            try
            {
                conn.Open();
                return true;
            }
            catch (Exception)
            {

                return false;
            }
            
        }
        //做一个关闭设置
        public void CloseConnection()
        {
            conn.Close();
            conn.Dispose();
        }
        //对数据库进行操作
        public SqlDataReader ExecReader(string sqlQuery)
        {
            //创建使用命令的对象
            SqlCommand cm = new SqlCommand();

            //设置让对象进行连接
            cm.Connection = conn;
            //sqlQuery是对象要用的命令
            cm.CommandText = sqlQuery;
            try
            {
                //执行查询操作
                SqlDataReader dr = cm.ExecuteReader();//执行用的

return dr; } catch (Exception) { return null; } } } }

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Data.SqlClient;
 4 
 5 namespace 数据库连接及使用
 6 {
 7     class 使用
 8     {
 9         public List<String> GetBook()
10         {
11             //创建存储的集合
12             List<String> boooks = new List<string>();
13             //创建数据库对象
14             连接 db = new 连接();
15             if (db.Openconnection())
16             {
17                 SqlDataReader dr = db.ExecReader("select * from Books");
18                 if (dr!=null)
19                 {
20                     while (dr.Read())//Read()是对dr数据进行判断，前进下一行，如果有就返回true
21                     {
22                         boooks.Add((int)dr["ID"] + "");
23                     }
24                 }
25                 //关闭数据库读取
26                 dr.Close();
27                 //关闭数据库连接
28                 db.CloseConnection();
29             }
30             return boooks;
31         }
32     }
33 }

using System;
using System.Collections.Generic;


namespace 数据库连接及使用
{
    class Program
    {
        static void Main(string[] args)
        {
            使用 m = new 使用();
           List<String> arr = m.GetBook();
            foreach (object o in arr)

            {

                Console.WriteLine(o.ToString() + " ");

            }
            Console.ReadKey();
        }
    }
}

create database BookShop
   go 
   use BookShop
go
create table Books
(
 ID    int    identity(1,1) primary key,
[Type]    nvarchar(20) not null,
Name    nvarchar(100) not null,
Author    nvarchar(30) not null,
Price    decimal check(Price>0) not null,
Cover    nvarchar(100) not null,
TotalNum    bigint check(TotalNum>10) not null,
SaleNum    bigint not null
)
go

insert into Books([Type],Name,Author,Price,Cover,TotalNum,SaleNum)
values(‘小说‘,‘三国演义‘,‘罗贯中‘,49.99,‘‘,100,1)
insert into Books([Type],Name,Author,Price,Cover,TotalNum,SaleNum)
values(‘小说‘,‘红楼梦‘,‘曹雪芹‘,69.99,‘‘,100,1)
insert into Books([Type],Name,Author,Price,Cover,TotalNum,SaleNum)
values(‘小说‘,‘水浒传‘,‘施耐庵‘,39.99,‘‘,100,1)
insert into Books([Type],Name,Author,Price,Cover,TotalNum,SaleNum)
values(‘小说‘,‘西游记‘,‘吴承恩‘,29.99,‘‘,100,1)
insert into Books([Type],Name,Author,Price,Cover,TotalNum,SaleNum)
values(‘小说‘,‘封神榜‘,‘姜子牙‘,999.99,‘‘,100,1)

select * FROM Books