Hello,
New to DS so would appreciate any help! I am looking at a join which has the following comment... "Performs cartesian product of the Facilty Expiry Date records with Time band codes".
Does anyone have any idea what this means?!
Thanks.
Join - comment info confusing!
Moderators: chulett, rschirm, roy
Re: Join - comment info confusing!
newby wrote:Hello,
New to DS so would appreciate any help! I am looking at a join which has the following comment... "Performs cartesian product of the Facilty Expiry Date records with Time band codes".
Does anyone have any idea what this means?!
Thanks.
Welcome aboard Newbie,
Cartesian product is a database concept rather than a Datastage concept so, It's not Datastage which confused you.
A cartesian product is is the result of an unrestricted join of two or more tables. ie Two or more tables are joined without any join conditions.
So if you are joining a table with 5 rows and a table with 6 rows after the join it will have 30 rows with all the possible combinations of columns in two tables.
Say, a table Employee with id and name is there and
1 a
and 2 b are the only rows it contains
Another table with only termination date is there and that is the only column it has
and let
2000-01-19
9999-12-31
are the rows contained by it
If you take a cartesian product of these tables it will look like
1 a 2000-01-19
1 a 9999-12-31
2 b 2000-01-19
2 b 9999-12-31
Hope that helps ..
Ajith
Re: Join - comment info confusing!
Ajith,
That's great - thanks very much for your help!
That's great - thanks very much for your help!