hive中表
-------------------
1.managed table
托管表。
删除表时，数据也删除了。
2.external table
外部表。
删除表时，数据不删。
hive命令
----------------
//创建表,external 外部表
$hive>CREATE external TABLE IF NOT EXISTS t2(id int,name string,age int)
COMMENT 'xx' ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' STORED AS TEXTFILE ;
//查看表数据
$hive>desc t2 ;
$hive>desc formatted t2 ;
//加载数据到hive表
$hive>load data local inpath '/home/centos/customers.txt' into table t2 ; //local上传文件
$hive>load data inpath '/user/centos/customers.txt' [overwrite] into table t2 ; //移动文件
//复制表
mysql>create table tt as select * from users ; //携带数据和表结构
mysql>create table tt like users ; //不带数据，只有表结构
hive>create table tt as select * from users ;
hive>create table tt like users ;
//count()查询要转成mr
$hive>select count(*) from t2 ;
$hive>select id,name from t2 ;
//
$hive>select * from t2 order by id desc ; //MR
//启用/禁用表
$hive>ALTER TABLE t2 ENABLE NO_DROP; //不允许删除
$hive>ALTER TABLE t2 DISABLE NO_DROP; //允许删除
//分区表,优化手段之一，从目录的层面控制搜索数据的范围。
//创建分区表.
$hive>CREATE TABLE t3(id int,name string,age int) PARTITIONED BY (Year INT, Month INT) ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' ;
//显式表的分区信息
$hive>SHOW PARTITIONS t3;
//添加分区,创建目录
$hive>alter table t3 add partition (year=2014, month=12);
//删除分区
hive>ALTER TABLE employee_partitioned DROP IF EXISTS PARTITION (year=2014, month=11);
//分区结构
hive>/user/hive/warehouse/mydb2.db/t3/year=2014/month=11
hive>/user/hive/warehouse/mydb2.db/t3/year=2014/month=12
//加载数据到分区表
hive>load data local inpath '/home/centos/customers.txt' into table t3 partition(year=2014,month=11);
//创建桶表
$hive>CREATE TABLE t4(id int,name string,age int) CLUSTERED BY (id) INTO 3 BUCKETS ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' ;
//加载数据不会进行分桶操作
$hive>load data local inpath '/home/centos/customers.txt' into table t4 ;
//查询t3表数据插入到t4中。
$hive>insert into t4 select id,name,age from t3 ;
//桶表的数量如何设置?
//评估数据量，保证每个桶的数据量block的2倍大小。
//连接查询
$hive>CREATE TABLE customers(id int,name string,age int) ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' ;
$hive>CREATE TABLE orders(id int,orderno string,price float,cid int) ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' ;
//加载数据到表
//内连接查询
hive>select a.*,b.* from customers a , orders b where a.id = b.cid ;
//左外
hive>select a.*,b.* from customers a left outer join orders b on a.id = b.cid ;
hive>select a.*,b.* from customers a right outer join orders b on a.id = b.cid ;
hive>select a.*,b.* from customers a full outer join orders b on a.id = b.cid ;
//explode,炸裂,表生成函数。
//使用hive实现单词统计
//1.建表
$hive>CREATE TABLE doc(line string) ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' ;1.下载hive2.1-tar.gz
2.tar开
$>tar -xzvf hive-2.1.0.tar.gz -C /soft //tar开
$>cd /soft/hive-2.1.0 //
$>ln -s hive-2.1.0 hive //符号连接
3.配置环境变量
[/etc/profile]
HIVE_HOME=/soft/hive
PATH=...:$HIVE_HOME/bin
4.验证hive安装成功
$>hive --version
5.配置hive,使用win7的mysql存放hive的元数据.
a)复制mysql驱动程序到hive的lib目录下。
...
b)配置hive-site.xml
复制hive-default.xml.template为hive-site.xml
修改连接信息为mysql链接地址，将${system:...字样替换成具体路径。
[hive/conf/hive-site.xml]
<property>
<name>javax.jdo.option.ConnectionPassword</name>
<value>root</value>
<description>password to use against metastore database</description>
</property>
<property>
<name>javax.jdo.option.ConnectionUserName</name>
<value>root</value>
<description>Username to use against metastore database</description>
</property>
<property>
<name>javax.jdo.option.ConnectionURL</name>
<value>jdbc:mysql://192.168.231.1:3306/hive2</value>
</property>
<property>
<name>javax.jdo.option.ConnectionDriverName</name>
<value>com.mysql.jdbc.Driver</value>
<description>Driver class name for a JDBC metastore</description>
</property> 6)在msyql中创建存放hive信息的数据库
mysql>create database hive2 ;
6)初始化hive的元数据(表结构)到mysql中。
$>cd /soft/hive/bin
$>schematool -dbType mysql -initSchema
hive命令行操作
------------------------
1.创建hive的数据库
$hive>hive --version //
$hive>hive --help //
$hive>create database mydb2 ; //
$hive>show databases ;
$hive>use mydb2 ;
$hive>create table mydb2.t(id int,name string,age int);
$hive>drop table t ;
$hive>drop table mydb2.t ;
$hive>select * from mydb2.t ; //查看指定库的表
$hive>exit ; //退出
$>hive //hive --service cli
$>hive //hive --service cli
通过远程jdbc方式连接到hive数据仓库
--------------------------------
1.启动hiveserver2服务器，监听端口10000
$>hive --service hiveserver2 &
2.通过beeline命令行连接到hiveserver2
$>beeline //进入beeline命令行(于hive --service beeline)
$beeline>!help //查看帮助
$beeline>!quit //退出
$beeline>!connect jdbc:hive2://localhost:10000/mydb2//连接到hibve数据
$beeline>show databases ;
$beeline>use mydb2 ;
$beeline>show tables; //显式表
使用Hive-jdbc驱动程序采用jdbc方式访问远程数据仓库
----------------------------------------------------
1.创建java模块
2.引入maven
3.添加hive-jdbc依赖
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.it18zhang</groupId>
<artifactId>HiveDemo</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>org.apache.hive</groupId>
<artifactId>hive-jdbc</artifactId>
<version>2.1.0</version>
</dependency>
</dependencies>
</project>4.App
package com.it18zhang.hivedemo;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
/**
* 使用jdbc方式连接到hive数据仓库，数据仓库需要开启hiveserver2服务。
*/
public class App {
public static void main(String[] args) throws Exception {
Class.forName("org.apache.hive.jdbc.HiveDriver");
Connection conn = DriverManager.getConnection("jdbc:hive2://192.168.231.201:10000/mydb2");
Statement st = conn.createStatement();
ResultSet rs = st.executeQuery("select id , name ,age from t");
while(rs.next()){
System.out.println(rs.getInt(1) + "," + rs.getString(2)) ;
}
rs.close();
st.close();
conn.close();
}
}