C#从数据库mysql读取数据

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usingSystem;

usingSystem.Collections.Generic;

usingSystem.ComponentModel;

usingSystem.Data;

usingSystem.Drawing;

usingSystem.Linq;

usingSystem.Text;

usingSystem.Threading.Tasks;

usingSystem.Windows.Forms;

usingMySql.Data.MySqlClient;

namespace电子商务

{

publicpartialclassForm1:Form

{

publicForm1()

{

InitializeComponent();

}

privatevoidForm1_Load(objectsender,EventArgse)

{

}

privatevoidbutton1_Click(objectsender,EventArgse)

{

stringstr ="Host=localhost;User ID=root;Password=;Port = 3306;DataBase=animals;Charset=utf8;";

MySqlConnectionconn =newMySqlConnection(str);

conn.Open();//

////拿到数据库并打开连接

//string sql = "select *from student";

//MySqlCommand cmd = new MySqlCommand(sql, conn);

//MySqlDataAdapter mda = new MySqlDataAdapter(cmd);

//DataSet ds = new DataSet();

//mda.Fill(ds);

//dataGridView1.DataSource = ds.Tables[0];

////MySqlDataReader dr = cmd.ExecuteReader();

//conn.Close();

/*1.访问数据库的五大步骤

2.拿到要发送的sql语句

3.执行 sql 语句

4.拿到执行后的聚过

5.关闭连接切记关闭连接

////1 拿到数据库的连接并打开连接

//string url = "User ID=root;Password=;Host=localhost;Port=3306;Database=xx;charset=xx;";

//MySqlConnection con = new MySqlConnection(url);

//con.Open();

////2.要拿到要发送的sql语句

//string sql = "select id from student where name='kobe'";

//MySqlCommand com = new MySqlCommand(sql, con);

//// 3 执行 sql 语句

//MySqlDataReader reader = com.ExecuteReader();

//reader.Read();// Read() 每次调用都会从结果集中返回一行数据

//reader.GetInt32(0);

/*1.访问数据库的五大步骤

2.拿到要发送的sql语句

3.执行 sql 语句

4.拿到执行后的聚过

5.关闭连接切记关闭连接

//1 拿到数据库的连接并打开连接

stringurl ="User ID=root;Password=;Host=localhost;Port=3306;Database=students;";

MySqlConnectioncon =newMySqlConnection(url);

con.Open();

//2.要拿到要发送的sql语句

stringsql ="select *from student where name='kobe'";

MySqlCommandcom =newMySqlCommand(sql, con);

// 3 执行 sql 语句

MySqlDataReaderreader = com.ExecuteReader();

reader.Read();// Read() 每次调用都会从结果集中返回一行数据

//reader.GetInt32(0);

Console.WriteLine(reader.GetInt32(0));

con.Close();

////对数据库进行增删改查

////1 拿到数据库的连接并打开连接

//string url = "User ID=root;Password=root;Host=localhost;Port=3306;Database=students;";

//MySqlConnection con = new MySqlConnection(url);

//con.Open();

//string sql = "insert into student values(11,'hahahaha','man',6)";//添加信息

//MySqlCommand cmd = new MySqlCommand(sql, con);

//int result = cmd.ExecuteNonQuery();

//Console.WriteLine("数据库打开结果："+result);

//con.Close();

//FindStudent("kobe");

}

publicstaticboolFindStudent(stringname)

{

boolb =false;

stringurl ="User ID=root;Password=root;Host=localhost;Port=3306;Database=students;";

MySqlConnectioncon =newMySqlConnection(url);

con.Open();

stringsql ="select *from studnet where name='{0}' ";

sql =string.Format(sql, name);

// Console.WriteLine(sql);

MySqlCommandcmd =newMySqlCommand(sql, con);

MySqlDataReaderreader = cmd.ExecuteReader();

b = reader.Read();

returnb;

}

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