Hive项目实战三

创建表

这里总共需要创建4张表，明明只有两个数据文件，为什么要创建4张表呢？因为这里创建的表要使用orc的压缩方式，而不使用默认的textfile的方式，orc的压缩方式要想向表中导入数据需要使用子查询的方式导入，即把从另一张表中查询到的数据插入orc压缩格式的表汇中，所以这里需要四张表，两张textfile类型的表user和video，两张orc类型的表user_orc和video_orc

1.先创建textfile类型的表

create table user(
videoId string,
uploader string,
age int,
category array,
length int,
views int,
rate float,
ratings int,
comments int,
relatedId array)
row format delimited
fields terminated by "\t"
collection items terminated by "&"
stored as textfile;

create table video(
uploader string,
videos int,
friends int)
row format delimited
fields terminated by "\t"
stored as textfile;

向两张表中导入数据，从hdfs中导入

load data inpath '数据文件在hdfs中的位置' into table user;

2.创建两张orc类型的表

create table user_orc(
videoId string,
uploader string,
age int,
category array,
length int,
views int,
rate float,
ratings int,
comments int,
relatedId array)
clustered by (uploader) into 8 buckets
row format delimited fields terminated by "\t"
collection items terminated by "&"
stored as orc;

create table video_orc(
uploader string,
videos int,
friends int)
clustered by (uploader) into 24 buckets
row format delimited
fields terminated by "\t"
stored as orc;

向两张表中导入数据

insert into table user_orc select *from user;
insert into table video_orc select *from video;

这时候数据就加载到两张表中了，可以进行简单的查看

select *from user_orc limit 10;
select *from video_orc limit 10;