hive学习001 hive的使用，

hive学习001 hive的使用，

概念

  hive是一个数据仓库（数据库与数据仓库概念我也不是很清楚），不过他可以建很多数据库，很多数据库下又会有很多的表。提供了一种HIVE QL的查询语言。

结构

 

（图选自hive 用户指导1.0，版本不同会有差异http://wenku.baidu.com/link?url=Oe4fznW4mkt5yS418-oPSFwGFEJYrco9NkGH-2LBMsdSztQ_jloUg6xKcGD3_pXewnNTMUA6X-UWAuIg8HioNu8kSwjyAnQRapUoCkz5vki点击打开链接）

使用

   HIVE提供了dbc、webgui、cli这样的接口：

1.CLI的使用

 使用的是Bitvise SSH Client的Linux远程桌面程序：步骤如图示

WEB-GUI使用

JDBC方式使用

   java程序中绑定hive数据库（类似于mysql、oracle数据库一类），wiki地址：https://cwiki.apache.org/confluence/display/Hive/HiveServer2+Clients#HiveServer2Clients-JDBC点击打开链接

 

import java.sql.SQLException; import java.sql.Connection; import java.sql.ResultSet; import java.sql.Statement; import java.sql.DriverManager;

public class HiveJdbcClient {   privatestatic String driverName ="org.apache.hive.jdbc.HiveDriver";     /**    * @param args    * @throws SQLException    */   publicstatic void main(String[] args) throws SQLException {       try{       Class.forName(driverName);     }catch (ClassNotFoundException e) {       // TODO Auto-generated catch block       e.printStackTrace();       System.exit(1);     }     //replace "hive" here with the name of the user the queries should run as     Connection con = DriverManager.getConnection("jdbc:hive2://localhost:10000/default","hive", "");//获取数据源     Statement stmt = con.createStatement();     String tableName ="testHiveDriverTable";     stmt.execute("drop table if exists "+ tableName);     stmt.execute("create table "+ tableName + " (key int, value string)");     // show tables     String sql ="show tables '" + tableName + "'";     System.out.println("Running: "+ sql);     ResultSet res = stmt.executeQuery(sql);     if(res.next()) {       System.out.println(res.getString(1));     }        // describe table     sql ="describe " + tableName;     System.out.println("Running: "+ sql);     res = stmt.executeQuery(sql);     while(res.next()) {       System.out.println(res.getString(1) +"\t" + res.getString(2));     }       // load data into table     // NOTE: filepath has to be local to the hive server     // NOTE: /tmp/a.txt is a ctrl-A separated file with two fields per line     String filepath ="/tmp/a.txt";     sql ="load data local inpath '" + filepath + "' into table " + tableName;     System.out.println("Running: "+ sql);     stmt.execute(sql);       // select * query     sql ="select * from " + tableName;     System.out.println("Running: "+ sql);     res = stmt.executeQuery(sql);     while(res.next()) {       System.out.println(String.valueOf(res.getInt(1)) +"\t" + res.getString(2));     }       // regular hive query     sql ="select count(1) from " + tableName;     System.out.println("Running: "+ sql);     res = stmt.executeQuery(sql);     while(res.next()) {       System.out.println(res.getString(1));     }   } }



接下来一篇就是SQL方言各类特性