Home > Software > Data-Warehouse > DataStage
Interview Questions   Tutorials   Discussions   Programs   Discussion   

DataStage - What is lookup table?

asked mar September 20, 2014 06:33 AM  

What is lookup table?


1 Answers

answered By Mswami   0  
Lookup table is a reference table in which we will pass a key column from source table and we will get the required  data once the key column matches.

Lookup Stage:

The Lookup stage is most appropriate when the reference data for all lookup stages in a job is small enough to fit into available physical memory. Each lookup reference requires a contiguous block of shared memory. If the Data Sets are larger than available memory resources, the JOIN or MERGE stage should be used.

Lookup stages do not require data on the input link or reference links to be sorted. Be aware, though, that large in-memory lookup tables will degrade performance because of their paging requirements. Each record of the output data set contains columns from a source record plus columns from all the corresponding lookup records where corresponding source and lookup records have the same value for the lookup key columns. The lookup key columns do not have to have the same names in the primary and the reference links.
   add comment

Your answer

Join with account you already have



Ready to start your tutorial with us? That's great! Send us an email and we will get back to you as soon as possible!