17-Hive DDL&DML

DDL：Data Defination Language
描述Hive表数据的结构：create alter drop.....

Hive构建在Hadoop之上
    Hive的数据存放在HDFS之上
    Hive的元数据可以存放在RDBMS之上

Database/Table

CREATE (DATABASE|SCHEMA) [IF NOT EXISTS] database_name
[COMMENT database_comment]
[LOCATION hdfs_path]
[WITH DBPROPERTIES (property_name=property_value, ...)];

default是Hive中默认的一个数据库
/user/hive/warehouse/

create database hive;

/user/hive/warehouse/<databasename>.db

DROP (DATABASE|SCHEMA) [IF EXISTS] database_name [RESTRICT|CASCADE];

create alter drop show desc use

基本数据类型
疯！！！！！！！！！！！！！！
int bigint float double decimal
boolean XXX
string
date/timestamp XXX

分隔符
行: \n
列: \001 ^A ==>
1 zhangsan 30
1$$$zhangsan$$$30
map/struct/array

Table
use ruozedata;
CREATE TABLE ruozedata_person
(id int comment 'this is id', name string comment 'this id name' )
comment 'this is ruozedata_person'
ROW FORMAT DELIMITED
FIELDS TERMINATED BY '\t' ;

create table ruozedata_emp
(empno int, ename string, job string, mgr int, hiredate string, salary double, comm double, deptno int)
ROW FORMAT DELIMITED
FIELDS TERMINATED BY '\t' ;

LOAD DATA LOCAL INPATH '/home/hadoop/data/emp.txt' OVERWRITE INTO TABLE ruozedata_emp;
local: 从本地文件系统加载数据到hive表
非local：从HDFS文件系统加载数据到hive表

OVERWRITE: 加载数据到表的时候数据的处理方式，覆盖
非OVERWRITE：追加

CREATE table ruozedata_emp2 as select * from ruozedata_emp;

CREATE table ruozedata_emp3 like ruozedata_emp;
ALTER TABLE ruozedata_emp3 RENAME TO ruozedata_emp3_new;

create alter drop show desc

创建表默认使用的是MANAGED_TABLE：内部表
ruozedata_emp_managed
drop：hdfs+meta

EXTERNAL：外部表
create EXTERNAL table ruozedata_emp_external
(empno int, ename string, job string, mgr int, hiredate string, salary double, comm double, deptno int)
ROW FORMAT DELIMITED
FIELDS TERMINATED BY '\t'
LOCATION "/ruozedata/external/emp" ;
drop: drop meta

hdfs://hadoop000:8020/ddddd
s3a://xxx/yyyy
s3n

create table ruozedata_emp4 like ruozedata_emp;

INSERT OVERWRITE TABLE ruozedata_emp4
select * FROM ruozedata_emp;

INSERT INTO TABLE ruozedata_emp4
SELECT empno,job, ename,mgr, hiredate, salary, comm, deptno from ruozedata_emp;

重跑：幂等 *****
log
2055 ==> 20
2054 ==> 20
....
1959 ==> 19

CREATE [TEMPORARY] [EXTERNAL] TABLE [IF NOT EXISTS] [db_name.]table_name -- (Note: TEMPORARY available in Hive 0.14.0 and later)
[(col_name data_type [COMMENT col_comment], ... [constraint_specification])]
[COMMENT table_comment]
[PARTITIONED BY (col_name data_type [COMMENT col_comment], ...)]
[CLUSTERED BY (col_name, col_name, ...) [SORTED BY (col_name [ASC|DESC], ...)] INTO num_buckets BUCKETS]
[SKEWED BY (col_name, col_name, ...) -- (Note: Available in Hive 0.10.0 and later)]
ON ((col_value, col_value, ...), (col_value, col_value, ...), ...)
[STORED AS DIRECTORIES]
[
[ROW FORMAT row_format]
[STORED AS file_format]
| STORED BY 'storage.handler.class.name' [WITH SERDEPROPERTIES (...)] -- (Note: Available in Hive 0.6.0 and later)
]
[LOCATION hdfs_path]
[TBLPROPERTIES (property_name=property_value, ...)] -- (Note: Available in Hive 0.6.0 and later)
[AS select_statement]; -- (Note: Available in Hive 0.5.0 and later; not supported for external tables)

CREATE [TEMPORARY] [EXTERNAL] TABLE [IF NOT EXISTS] [db_name.]table_name
LIKE existing_table_or_view_name
[LOCATION hdfs_path];

data_type
: primitive_type
| array_type
| map_type
| struct_type
| union_type -- (Note: Available in Hive 0.7.0 and later)

array_type
: ARRAY < data_type >

map_type
: MAP < primitive_type, data_type >

struct_type
: STRUCT < col_name : data_type [COMMENT col_comment], ...>

union_type
: UNIONTYPE < data_type, data_type, ... > -- (Note: Available in Hive 0.7.0 and later)

row_format
: DELIMITED [FIELDS TERMINATED BY char [ESCAPED BY char]] [COLLECTION ITEMS TERMINATED BY char]
[MAP KEYS TERMINATED BY char] [LINES TERMINATED BY char]
[NULL DEFINED AS char] -- (Note: Available in Hive 0.13 and later)
| SERDE serde_name [WITH SERDEPROPERTIES (property_name=property_value, property_name=property_value, ...)]

file_format:
: SEQUENCEFILE
| TEXTFILE -- (Default, depending on hive.default.fileformat configuration)
| RCFILE -- (Note: Available in Hive 0.6.0 and later)
| ORC -- (Note: Available in Hive 0.11.0 and later)
| PARQUET -- (Note: Available in Hive 0.13.0 and later)
| AVRO -- (Note: Available in Hive 0.14.0 and later)
| INPUTFORMAT input_format_classname OUTPUTFORMAT output_format_classname

constraint_specification:
: [, PRIMARY KEY (col_name, ...) DISABLE NOVALIDATE ]
[, CONSTRAINT constraint_name FOREIGN KEY (col_name, ...) REFERENCES table_name(col_name, ...) DISABLE NOVALIDATE

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