參數(shù)說明

示例代碼中的參數(shù)說明如下。

示例代碼

• Java示例代碼：

  說明

  以Maven項(xiàng)目為例，請(qǐng)先在pom.xml文件中添加DriverManager依賴，代碼示例：

  <dependency>
   <groupId>mysql</groupId>
   <artifactId>mysql-connector-java</artifactId>
   <version>8.0.27</version>
  </dependency>

  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()) {
  
              String selectSql = "SELECT * FROM `courses`";            //輸入希望執(zhí)行的SQL。
              resultSet = statement.executeQuery(selectSql);
  
              while (resultSet.next()) {
                  System.out.println(resultSet.getString("name"));
              }
          }
          catch (SQLException e) {
              e.printStackTrace();
          }
      }
  }

• Python3示例代碼：

  說明

  請(qǐng)先安裝PyMySQL。

  • Python3安裝命令：pip3 install PyMySQL

  • Python2安裝命令：pip install pymysql==0.9.3

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

• C示例代碼：

  說明

  請(qǐng)先安裝mysql.h頭文件，以CentOS為例，執(zhí)行如下命令：

  sudo yum install mysql-devel

  #include <stdio.h>
  #include <mysql.h>
  #include <string.h>
  
  int main(void)
  {
      MYSQL *t_mysql;
  
      MYSQL_RES       *res = NULL;
      MYSQL_ROW       row;
      char            *query_str = NULL;
      int             rc, i, fields;
      int             rows;
  
      char select[] = "select * from courses";    // 輸入希望執(zhí)行的SQL。
      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 0;
      }
  
      fields = mysql_num_fields(res);
      while ((row = mysql_fetch_row(res))) {
          for (i = 0; i < fields; i++) {
              printf("%s\t", row[i]);
          }
          printf("\n");
      }
      mysql_close(t_mysql);
  
  }
                      

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