Hi,
I'm interested in using the columnar feature, and after doing some intinial research, I found that Teradata automatically determines if a column should be row or column format. I was hoping to get more information on how Teradata actually determines this, and if there is a certain way to enable this, or if the DDLs have to be in a certain format?
I did find many resources online with sample DDLs. In some, after the PARTITION BY COLUMN statement, the columns are specfied, and then ROWs are specfied. In others, they are not specified at all:
create table employee_hybrid
(emp_no integer,
dept_no integer,
first_name varchar(20),
last_name varchar(20),
salary decimal(10,2))
no primary index
partition by column
(emp_no no auto compress,
dept_no
,Row (first_name, last_name, salary)
no auto compress);
create table employee_columnar
(emp_no integer,
dept_no integer,
first_name varchar(20),
last_name varchar(20),
salary decimal(10,2))
no primary index
partition by column;
My question is, if Teradata automatically deterimnes which format to store, then how exactly does it do so, and what format would the DDLs have to be in? Would the second example be enough?
I also found a ppt deck from Teradata labs here:
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CDAQFjAA&url=http%3A%2F%2Fwww.monash.com%2Fuploads%2FTeradata-Columnar-September-2011.ppt&ei=ERyBUcmGH8PA4AOA3YDoCg&usg=AFQjCNEYsGfnFui6LGeurey__7FK3jFt1Q&sig2=sok3PuDeSRyoR3ISrDAywg&bvm=bv.45921128,d.dmg
The ppt indicates that Teradata automatically determines which format, but doesn't go into much detail afterwards. Any insight would be appreciated.
Thanks