Hive: HiveQL Data Defination

• DataBase

hive>show databases;

hive>show databases like 'h.*';

hive>describe database mydb;

hive>describe database extended mydb;

hive>create database  mydb;

hive>create database if not exists mydb;

hive>create database mydb location '/my/prefered/direcotry';

hive>create database mydb with dbproperties ('creator'='zhj', 'date'='2014-3-24');

hive>use mydb;

hive>drop database if exists mydb;

hive>drop database if exists mydb cascade;

hive>alter database mydb set dbproperties ('edited-by'='jack');

• Tables

create table if not exists mydb.employess(

  name               string

                          comment 'Employee name',

  salary               float  

                          comment 'Employee salary',

  subordinates    array<string> 

                          comment 'Names of subordinates',

  deductions       map<string, float>

                          comment 'Keys are deduction names,values are percentages',

  address           struct<stree:string, city:string, state:string, zip:int>

                          comment 'Home address')

  comment 'description of the table'

  tblproperties ('creator'='zhj', 'created_at'='2014-3-23',...)

  location '/usr/hive/warehouse/mydb.db/employees';

------

create table if not exists mydb.employees2 like mydb.employees;

describe extended mydb.employees;

describe mydb.employees.salary;

DROP TABLE IF EXISTS employees;

ALTER TABLE log_messages RENAME TO logmsgs;

alter table user_published_pictures SET SERDEPROPERTIES ('field.delim'=',');

create external table table-name if not exists

like existed-table

location 'path/to/external-data-store';

References

https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL#LanguageManualDDL-AlterTable%2FPartitionLocation