2021年大数据HBase（十一）：Apache Phoenix的视图操作

2021-10-11 16:31:42 浏览数 (1)

Apache Phoenix的视图操作

一、应用场景

因为我们之前已经创建了 MOMO_CHAT:MSG 表，而且数据添加的方式都是以PUT方式原生API来添加的。故此时，我们不再需要再使用Phoenix创建新的表，而是使用Phoenix中的视图，通过视图来建立与HBase表之间的映射，从而实现数据快速查询。

二、视图介绍

我们可以在现有的HBase或Phoenix表上创建一个视图。表、列蔟和列名必须与现有元数据完全匹配，否则会出现异常。当创建视图后，就可以使用SQL查询视图，和操作Table一样。

三、语法说明

代码语言：javascript复制
create view "my_hbase_table" (
  rowkey varchar primary key,
  列族.列名1 数据类型,
  列族.列名2 数据类型,
  ....
)

考虑以下几个问题：

  1. 视图如何映射到HBase的表？ 视图的名字必须是：命名空间.表名
  2. 视图中的列如何映射到HBase的列蔟和列？  列名必须是：列蔟.列名
  3. 视图中的类如何映射到HBase的ROWKEY？ 指定某个列为primary key，自动映射ROWKEY

四、建立MOMO_CHAT:MSG的视图

1、参考SQL语句

-- 创建MOMO_CHAT:MSG视图

代码语言：javascript复制
CREATE VIEW
IF
	NOT EXISTS "MOMO_CHAT"."MSG" (
		"pk" VARCHAR PRIMARY KEY,  -- 指定ROWKEY映射到主键
		"C1"."msg_time" VARCHAR,
		"C1"."sender_nickyname" VARCHAR,
		"C1"."sender_account" VARCHAR,
		"C1"."sender_sex" VARCHAR,
		"C1"."sender_ip" VARCHAR,
		"C1"."sender_os" VARCHAR,
		"C1"."sender_phone_type" VARCHAR,
		"C1"."sender_network" VARCHAR,
		"C1"."sender_gps" VARCHAR,    "C1"."receiver_nickyname" VARCHAR,
		"C1"."receiver_ip" VARCHAR,
		"C1"."receiver_account" VARCHAR,
		"C1"."receiver_os" VARCHAR,
		"C1"."receiver_phone_type" VARCHAR,
		"C1"."receiver_network" VARCHAR,
		"C1"."receiver_gps" VARCHAR,
		"C1"."receiver_sex" VARCHAR,
		"C1"."msg_type" VARCHAR,
	  "C1"."distance" VARCHAR 
	);

2、尝试查询一条数据

代码语言：javascript复制
SELECT * FROM "MOMO_CHAT"."MSG" LIMIT 1;

五、完成陌陌查询案例

1、需求

根据日期、发送人账号、接收人账号查询历史消息

2、编写SQL实现陌陌案例

代码语言：javascript复制
SELECT
	C1."sender_account",
	C1."receiver_account",
	C1."msg_time",
	C1."message" 
FROM
	MOMO_CHAT.MSG 
WHERE
	substr( C1."msg_time", 0, 10 ) = '2021-07-16' 
	AND C1."sender_account" = '18461866438' 
	AND C1."receiver_account" = '13641568674';

3、使用java连接Phoenix: 

代码语言：javascript复制
@Override    
public List<Msg> getMessage(String date, String sender, String receiver) throws Exception {
        Class.forName(PhoenixDriver.class.getName());         
        Connection connection = DriverManager.getConnection("jdbc:phoenix:node1:2181");
        PreparedStatement ps = connection.prepareStatement("SELECT * FROM MOMO_CHAT.MSG T WHERE substr("msg_time", 0, 10) = ? " 
        	  "AND T."sender_account" = ? " 
        	  "AND T."receiver_account" = ? ");
        ps.setString(1, date);         
        ps.setString(2, sender);
        ps.setString(3, receiver);        
        ResultSet rs = ps.executeQuery();        
        List<Msg> msgList = new ArrayList<>();
        while(rs.next()) {            
        	Msg msg = new Msg();            
        	msg.setMsg_time(rs.getString("msg_time"));            
        	msg.setSender_nickyname(rs.getString("sender_nickyname"));            
        	msg.setSender_account(rs.getString("sender_account"));            
        	msg.setSender_sex(rs.getString("sender_sex"));            
        	msg.setSender_ip(rs.getString("sender_ip"));            
        	msg.setSender_os(rs.getString("sender_os"));            
        	msg.setSender_phone_type(rs.getString("sender_phone_type"));            
        	msg.setSender_network(rs.getString("sender_network"));            
        	msg.setSender_gps(rs.getString("sender_gps"));            
        	msg.setReceiver_nickyname(rs.getString("receiver_nickyname"));            
        	msg.setReceiver_ip(rs.getString("receiver_ip"));            
        	msg.setReceiver_account(rs.getString("receiver_account"));            
        	msg.setReceiver_os(rs.getString("receiver_os"));            
        	msg.setReceiver_phone_type(rs.getString("receiver_phone_type"));            
        	msg.setReceiver_network(rs.getString("receiver_network"));            
        	msg.setReceiver_gps(rs.getString("receiver_gps"));            
        	msg.setReceiver_sex(rs.getString("receiver_sex"));            
        	msg.setMsg_type(rs.getString("msg_type"));            
        	msg.setDistance(rs.getString("distance"));            
        	msgList.add(msg);        
        }
        return msgList;    
}