what is the main differences between Lookup, Join and Merge
stages?
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Answer Posted / maruthi
ALL THESE THREE(MERGE,JOIN,LOOKUP) ARE USED TO JOIN TABLES
BASED ON THE KEY COLUMNS. AND THE DIFFERENCES ARE:
1.)MAIN DIFFERENCE:ALL THESE THREE WILL DIFFER ON THE
POPULATION OF DATA ONCE AFTER KEY COLUMN MATCHES,AND THE
MEMORY USED TO STORE TABLES.
MERGE:-CAN HAVE ANY NUMBER OF INPUT LINKS,SINGLE O/P
LINK,AND NO OF REJECT LINKS AS MANY OF UPDATE LINKS,SO WE
CAN HAVE REJECT DATA IN ANOTHER TABLES,(JOINER DONT
SUPOERTS ANT REFERENCE OR REJECT LINKS)
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