please find the below inforamtion which differentiates JOINS LOOK UP and MERGE stages.
may be bit tough to read(format)..
u can follow the below example for reading ...
model for joins is RDBMS,model for look up is RAM LU table and model for merge is Master-update
JOINS LOOK UP MERGE
MODEL RDBMS-Style relational , Source-in RAM LU table , Master-Update(s)
MEMORY light , heavy , light
# AND NAMES OF INPUT "2 or more:left,right" , "1 source ,N LU tables" , 1 Master N update(s)
MANDATORY INPUT SORT both inputs , no , all inputs
DUPLICATES IN PRIMARY INPUT ok(x-product) , ok , warning!
DUPLICATES IN SECONDARY INPUT ok(x-product) , warning! , ok when only N=1
OPTIONS ON UNMATCHED PRIMARY "keep(left outer),drop(inner)" ,[fail] continue|drop|reject , [keep]|drop
OPTIONS ON UNMATCHED SECONDARY "keep(right outer),drop (inner)" , none , capture in reject set(s)
OUTPUTS 1 , "1 out ,1 reject" , "1 out,n rejects"
CAPTURED IN REJECT SETS nothing , unmatched primary entries , unmatched secondary entries
