Datastage Interview Questions and Answers Part-4
31) Differentiate between Operational Datastage (ODS) and Data warehouse?
We can say, ODS is a mini data warehouse. An ODS doesn’t contain information for more than 1 year while a data warehouse contains detailed information regarding the entire business.
32) NLS stands for what in Datastage?
NLS means National Language Support. It can be used to incorporate other languages such as French, German, and Spanish etc. in the data, required for processing by data warehouse. These languages have same scripts as English language.
33) Can you explain how could anyone drop the index before loading the data in target in Datastage?
In Datastage, we can drop the index before loading the data in target by using the Direct Load functionality of SQL Loaded Utility.
34) Does Datastage support slowly changing dimensions ?
Yes. Version 8.5 + supports this feature
35) How can one find bugs in job sequence?
We can find bugs in job sequence by using DataStage Director.
36) How complex jobs are implemented in Datstage to improve performance?
In order to improve performance in Datastage, it is recommended, not to use more than 20 stages in every job. If you need to use more than 20 stages then it is better to use another job for those stages.
37) Name the third party tools that can be used in Datastage?
The third party tools that can be used in Datastage, are Autosys, TNG and Event Co-ordinator. I have worked with these tools and possess hands on experience of working with these third party tools.
38) Define Project in Datastage?
Whenever we launch the Datastage client, we are asked to connect to a Datastage project. A Datastage project contains Datastage jobs, built-in components and Datastage Designer or User-Defined components.
39) How many types of hash files are there?
There are two types of hash files in DataStage i.e. Static Hash File and Dynamic Hash File. The static hash file is used when limited amount of data is to be loaded in the target database. The dynamic hash file is used when we don’t know the amount of data from the source file.
40) Define Meta Stage?
In Datastage, MetaStage is used to save metadata that is helpful for data lineage and data analysis.