Difference between JOIN,LOOKUP,MERGE?

Answer Posted / rajesh pandi

1.if a source have huge volume of datea, then that time we have to use join, or merge stage
2.if you want to filter the unmatched record from reference files, then we should use merge stage only
3.join stage can have 'n' number of input link(1 left link 1right link other links called intermediate link) but only one output link...
Merge stage cane have 'n' no of input link (1 master link n update link) and one output link And equal no of reject link as same as update link
Look up stage can have n number of input link and 1 output link and one reject link
4.join we can do all join operation inner, left outer, right outer, full outer but in merge and lookup we can only do a inner join and left outer join

Is This Answer Correct ?    0 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

What could be a data source system?

587


What is usage analysis in datastage?

831


Which warehouse using in your datawarehouse

1690


How many types of sorting methods are available in datastage?

642


What all the types of jobs you developed?

680






Name the different types of Lookups in Datastage?

739


1.new record it will insert but changes of natural key is not present in taget i want to update (here key is composite natural key )can any one help this to explan how to do

1665


Is possible to create skid in dim,fact tables?

2197


In work load management there are three options of Low priority, Medium priority and High Priority Jobs which can be used for resource management. why this feature is developed when there is already jobs prescheduled by scheduler or autosys. what will be the use of workload management then?

1057


What is use Array size in datastage

1321


What are the different plug-ins stages used in your projects?

637


Explain Quality stage?

678


Is the value of staging variable stored temporarily or permanently?

587


How to perform incremental load in datastage?

685


why do u need the IOS upgradation in a FC switch

1886