Data warehousing interview questions

For Informatica:

Let them know which version you are familiar with as well as what role. Informatica 7.x has divided the developer and administrator roles.

You will most likely be asked specific questions for building a mapping and workflow. Know what the difference is between sttic and reusable objects for both. Be prepared to demonstrate how to create a connection, source definition (flat file and relational), use expression transformation, lookups (connected and disconnected), aggregators, normalizers, update strategies, how to modify source and target sql overrides, etc.

For Erwin:

Know the difference between Logical and Physical models.
Know how to use the Reverse Engineer and Comparison features.
The dimension model feature is pretty weak, but you might want to know how Erwin treats dimensional modeling.

Other topics:

Anything you know about RDBMS is worth discussing.

In Oracle, you can talk about referential integrity as it applies to DW. Views and Materialized Views, Partitioning, Bitmap Indexing (when to use), and any other specifics as related to DW (for 10g there is the new Bitmap join Index).

Always, always offer details of your knowledge, and ask questions to get the customer's perspectives (you do not want to push Kimball concepts if the customer is hard-set on Inmon).

Anything you can bring to the table regarding the customers business systems (i.e. SAP, Peoplesoft, etc.) will help separate you from the pack. Also anything you know about business processes such as:, Order Fulfillment, Inventory Analysis, Finance, etc. will also separate you.


3. Adapted from response by Shaquille on Wednesday, August 11, 2004

Here are the few questions that might be posed:

Data Warehousing questions:
1) What is source qualifier?
2) Difference between DSS & OLTP?
3) Explain grouped cross tab?
4) Hierarchy of DWH?
5) How many repositories can we create in Informatica?
6) What is surrogate key?
7) What is difference between Mapplet and reusable transformation?
8) What is aggregate awareness?
9) Explain reference cursor?
10) What are parallel querys and query hints?
11) DWH architecture?
12) What are cursors?
13) Advantages of de normalized data?
14) What is operational data source (ODS)?
15) What is meta data and system catalog?
16) What is factless fact schema?
17) What is confirmed dimension?
18) What is the capacity of power cube?
19) Difference between PowerPlay transformer and power play reports?
20) What is IQD file?
21) What is Cognos script editor?
22) What is difference macros and prompts?
23) What is power play plug in?
24) Which kind of index is preferred in DWH?
25) What is hash partition?
26) What is DTM session?
27) How can you define a transformation? What are different types of transformations in Informatica?
28) What is mapplet?
29) What is query panel?
30) What is a look up function? What is default transformation for the look up function?
31) What is difference between a connected look up and unconnected look up?
32) What is staging area?
33) What is data merging, data cleansing and sampling?
34) What is up date strategy and what are th options for update strategy?
35) OLAP architecture?
36) What is subject area?
37) Why do we use DSS database for OLAP tools?

Business Objects Popular Q&A:
38) What is a universe?
39) Analysis in business objects?
40) Who launches the supervisor product in BO for first time?
41) How can you check the universe?
42) What are universe parameters?
43) Types of universes in business objects?
44) What is security domain in BO?
45) Where will you find the address of repository in BO?
46) What is broad cast agent?
47) In BO 4.1 version what is the alternative name for broadcast agent?
48) What services the broadcast agent offers on the server side?
49) How can you access your repository with different user profiles?
50) How many built-in objects are created in BO repository?
51) What are alertors in BO?
52) What are different types of saving options in web intelligence?
53) What is batch processing in BO?
54) How can you first report in BO by using broadcast agent?
55) Can we take report on Excel in BO?