What are the various types of lookups in DataStage?
There are two types of Lookups in Datastage i.e. Normal lkp and Sparse lkp.
Which three lookup types may be performed in the lookup stage?
The Lookup stage can have a reference link, a single input link, a single output link, and a single rejects link.
What is sparse lookup in DataStage?
A sparse lookup is also known as a direct lookup because the lookup is performed directly on the database. Typically, you use a sparse lookup when the target table is too large to fit in memory. You can also use the sparse lookup method for real-time jobs. You can use the sparse lookup method only in parallel jobs.
What are the two types of lookups?
There are two kinds of lookup operations: Datacap database lookups and third-party lookups.
How does lookup work in DataStage?
The Lookup stage has a stream input and a reference input. The stage uses one or more key columns in the stream input to search for data in a reference table. The data from the reference table is then added to the stream output.
How does lookup work in Datastage?
What is the difference between lookup and merge join transformation?
Merge Join allows you to join to multiple columns based on one or more criterion, whereas a Lookup is more limited in that it only fetches a one or more values based on some matching column information — the lookup query is going to be run for each value in your data source (though SSIS will cache the data source if …
What is the disadvantage of using sparse look up over normal look up?
Normal will provide data for an in-memory look up whereas Sparse will access the database directly. Normal might provide poor performance when the reference data is huge as it has to load large data into memory.
What is sequential file in Datastage?
The Sequential File stage is a file stage that allows you to read data from or write data one or more flat files. The stage can have a single input link or a single output link, and a single rejects link. When you edit a Sequential File stage, the Sequential File stage editor appears.
What’s the difference between VLOOKUP and Hlookup?
The most commonly used LOOKUP functions in Excel are VLOOKUP and HLOOKUP. VLOOKUP allows you to search a data range that is set up vertically. HLOOKUP is the exact same function, but looks up data that has been formatted by rows instead of columns.