南大通用GBase 8a之视频数据存取demo

概述

在GBase8a数据库中视频文件如何导入，以及如何读取视频文件并播放。

实现步骤

（1）建表

CREATE TABLE "vtest" (
 "v_name" varchar(50) DEFAULT NULL,
 "v_data" longblob
)  ;   
注意： longblob类型，目前最大支持64MB的存储空间

（2）视频文件数据导入数据库

gbase> INSERT INTO vtest (v_name, v_data) VALUES ('1.mp4',  LOAD_FILE('/home/gbase/1.mp4')  );
Query OK, 1 row affected (Elapsed: 00:00:00.21)

（3）从数据库中读取视频文件并播放

def read_video_from_mysql(host, user, password, db, table, video_name, port):
   try:
       conn = pymysql.connect(
           host=host,
           user=user,
           password=******,
           database=db,
           port=port,
           charset='utf8mb4'
       )
       cursor = conn.cursor()

       sql = f"SELECT v_data FROM {table} WHERE v_name = %s"
       cursor.execute(sql, (video_name,))
       result = cursor.fetchone()

       if not result or not result[0]:
           print("未找到对应的视频数据！")
           return

       video_blob = result[0]
       with tempfile.NamedTemporaryFile(suffix='.mp4', delete=False) as temp_file:
           temp_file.write(video_blob)
           temp_file_path = temp_file.name

       cap = cv2.VideoCapture(temp_file_path)
       if not cap.isOpened():
           print("无法打开视频文件！")
           os.unlink(temp_file_path)
           return

       while cap.isOpened():
           ret, frame = cap.read()
           if ret:
               cv2.imshow('Video from GBASE', frame)
               if cv2.waitKey(25) & 0xFF == ord('q'):
                   break
           else:
               break

       cap.release()
       cv2.destroyAllWindows()
       os.unlink(temp_file_path)

   except pymysql.MySQLError as e:
       print(f"数据库操作错误：{e}")
   except Exception as e:
       print(f"程序执行错误：{e}")
   finally:
       if 'cursor' in locals():
           cursor.close()
       if 'conn' in locals():
           conn.close()

if __name__ == "__main__":
   read_video_from_mysql(
       host="192.168.56.101",
       user="gbase",
       password="******",
       db="vc_a.test",
       table="vtest",
       video_name="1.mp4",
       port=5258
   )

（4）验证执行播放效果

视频信息可以正常播放