Connect to a database by using an application

Step 1: Obtain the connection information of a database

1. Log on to the DMS Database Lab console.
2. In the left-side navigation pane, right-click the required instance to which the database belongs.
3. Select Get connection information from the shortcut menu. In the dialog box that appears, you can view the connection information of the database.
   
   The following figure shows the Connection information dialog box.

Step 2: Connect to the database by using an application

• Use Java to connect to the database:

  import java.sql.Connection;
  import java.sql.DriverManager;
  import java.sql.ResultSet;
  import java.sql.Statement;
  
  public class DatabaseConnection
  {
      public static void main(String args[]) {
          String connectionUrl= "jdbc:mysql://Host:Port/myDatabase";    
  
          ResultSet resultSet;
  
          try (Connection connection=DriverManager.getConnection(connectionUrl,"myUsername","myPassword");  
               Statement statement = connection.createStatement()) {
  
              // Query the courses table.
              String selectSql = "SELECT * FROM `courses`"; 
              resultSet = statement.executeQuery(selectSql);
  
              while (resultSet.next()) {
                  // Display the name column in the courses table.
                  System.out.println(resultSet.getString("name"));
              }
          }
          catch (SQLException e) {
              e.printStackTrace();
          }
      }
  }

• Use Python to connect to the database:

  import pymysql
  
  connection = pymysql.connect(host='Host',     
                         port=Port,
                         user='myUsername',
                         passwd='myPassword',
                         db='myDatabase')
  
  try:
      with connection.cursor() as cursor:
          // Query the courses table.
          sql = "SELECT * FROM `courses`"        
          cursor.execute(sql)
          for result in cursor:
               // Display the query result.
               print(result)
  finally:
      connection.close()

• Use C to connect to the database:

  #include <stdio.h>
  #include <mysql.h>
  #include <string.h>
  
  void main(void)
  {
      MYSQL *t_mysql;
  
      MYSQL_RES       *res = NULL;
      MYSQL_ROW       row;
      char            *query_str = NULL;
      int             rc, i, fields;
      int             rows;
  
      // Query the courses table.
      char select[] = "select * from courses";
      t_mysql = mysql_init(NULL);
  
      if(NULL == t_mysql){
          printf("init failed\n");
      }
  
      if(NULL == mysql_real_connect(t_mysql, Host, myUsername, myPassword, myDatabase,
              Port, NULL, 0)){
          printf("connect failed\n");
      }
  
      if(mysql_real_query(t_mysql, select, strlen(select)) ! = 0){
          printf("select failed\n");
      }
  
      res = mysql_store_result(t_mysql);
      if (NULL == res) {
           printf("mysql_restore_result(): %s\n", mysql_error(t_mysql));
           return -1;
      }
  
      fields = mysql_num_fields(res);
      while ((row = mysql_fetch_row(res))) {
          // Display each column in the courses table.
          for (i = 0; i < fields; i++) {
              printf("%s\t", row[i]);
          }
          printf("\n");
      }
      mysql_close(t_mysql);
  
  }