Study notes of C [8] SQL [1]

Download here SQL, I downloaded it 2019 edition , The installation link is placed below ：

SQL server Download and install the tutorial _H_2239903439 The blog of -CSDN Blog _sql Download the installation tutorial SQL server（2019 edition ） Install one 、SQL server download 1、SQL server Not much to say , Go straight to the point . If you can download it on the official website, try to download it on the official website （ Install on one side SQL server Download at the same time SSMS）. Download link ：SQL server Official website 2、 Under the download bar , Click to download ------ Double click the file to install 3、 The type of installation we need is to choose “ basic （B）”.3、 Don't talk nonsense , Accept and it's over . How can I marry you if I don't accept it ？4、 Choose your installation path , The default installation path is C disc , alternate path （ It depends on the situation ）.5、 After a long wait .6、 Click on “ install SSMS”.https://blog.csdn.net/qq_42681203/article/details/109442893?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522165063245516780271934148%2522%252C%2522scm%2522%253A%252220140713.130102334..%2522%257D&request_id=165063245516780271934148&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2~all~sobaiduend~default-1-109442893.142%5Ev9%5Econtrol,157%5Ev4%5Econtrol&utm_term=SQL+server%E4%B8%8B%E8%BD%BD&spm=1018.2226.3001.4187

  Some problems will be encountered during installation , You can see the following link , Basically solve the problem ：

SQL Server（ solve the problem ） The connection to the server was established successfully , But an error occurred during the login process .(provider: Shared Memory Provider, error:0 - There are no processes on the other end of the pipe ._AoboSir The blog of -CSDN Blog _ The connection to the server was established successfully , But an error occurred during the login process If you're using a newly created SQL Server User name and password The following problems occur when connecting to the database . Reading this blog can help you solve this problem . The connection to the server was established successfully , But an error occurred during the login process .(provider: Shared Memory Provider, error:0 - There are no processes on the other end of the pipe .)(Microsoft SQL Server, error ：233) There are no processes on the other end of the pipe . Action in question https://blog.csdn.net/github_35160620/article/details/52676416?spm=1001.2014.3001.5506

【 example 1】 Create a connection with the native SQL Server Database connection , And use exception handling .

According to the title requirements , Connect SQL Server The user name used for database is sa、 The password for 123456789,【 The account and password here can be set by yourself 】 The database connected is Test.【 Pay attention to the name on your database 】, There was a problem signing in here , You can see the following link ：

Unable to open the database requested by login _weixin_34216036 The blog of -CSDN Blog System.Data.EntityException: The underlying provider failed on Open. ---> System.Data.SqlClient.SqlException: Unable to open the database requested by login "CivilProductAdShow". Login failed . user 'gpwebuser' Login failed .1. Open the Database Enterprise Manager , Then select the database --- Security ...https://blog.csdn.net/weixin_34216036/article/details/93864674?ops_request_misc=&request_id=&biz_id=102&utm_term=VS%E6%98%BE%E7%A4%BA%E6%95%B0%E6%8D%AE%E5%BA%93%E8%BF%9E%E6%8E%A5%E5%A4%B1%E8%B4%A5%EF%BC%8C%E6%97%A0%E6%B3%95%E7%99%BB%E5%BD%95%E6%89%80%E8%AF%B7%E6%B1%82%E7%9A%84%E6%95%B0%E6%8D%AE%E5%BA%93&utm_medium=distribute.pc_search_result.none-task-blog-2~all~sobaiduweb~default-5-93864674.142%5Ev9%5Econtrol,157%5Ev4%5Econtrol&spm=1018.2226.3001.4187

  Need to be in SQL Create a new database named Test The database of , To show that the link is successful

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace SQL
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            // Write database connection string 
            string connStr = "Data source=.;Initial Catalog=Test;User ID=sa;Password=123456789";
            // establish SqlConnection Example 
            SqlConnection conn = null;
            try
            {
                conn = new SqlConnection(connStr);
                // Open database connection 
                conn.Open();
                MessageBox.Show(" Database connection successful ！");
            }
            catch (Exception ex)
            {
                MessageBox.Show(" Database connection failed ！" + ex.Message);
            }
            finally
            {
                if (conn != null)
                {
                    // Close database connection 
                    conn.Close();
                }
            }
        }
    }
}