Data Warehousing Interview Questions

1) Explain some disadvantages of data ware house?

These are some of the disadvantages of data ware house: –

1) It represents a very large project with a very broad scope which is a big disadvantage.
2) Upfront costs are very huge and the duration of the project from the start to the end user is significant.
3) It is inflexible and unresponsive to the departmental needs.

2) Explain about the top design?

In a top design model data ware house is designed in a normalized enterprise model. This is chiefly used for business intelligence and management capabilities. Data used for business purpose and management can be met through a data ware house. It is used to generate dimensional views and is known to be good and stable against business changes.

3) Explain about the non-volatile feature of data ware house?

Data once written and saved in data ware house is static and it can never be deleted and over written once confirmed. It will be static and read-only. This can be used for future reporting and it allows good security feature.

4) What are the different interconnected layers of a data ware house?

There are four different interconnected layers they are: –
? Operational database layer
? Informational access layer
? Data access layer
? Meta data layer.

5) What do you know about Data warehousing?

Data warehousing is used for reporting and analysis of the data. It is primarily used to analyze data. Some of the additional uses of it are extraction and retrieval of data, manage, load and manipulate data. It has various tools which can transform, load, extract and manage the data.

6) Explain about the time variant feature of Data ware housing?

Data ware house detects and tracks all the changes according to time. This allows a database developer to detect the changes across time which helps him to keep a log.

7) Explain about the top design?

In a top design model data ware house is designed in a normalized enterprise model. This is chiefly used for business intelligence and management capabilities. Data used for business purpose and management can be met through a data ware house. It is used to generate dimensional views and is known to be good and stable against business changes.

8) Explain about hybrid design model?

Due to the various risks and disadvantages presented by top down and bottom down models it has become imperative that Hybrid methodologies be used. This is used for fast turn around time and enterprise wide data consistency. This uses features and benefits from top down and bottom down models.

9) State some of the disadvantages of data ware houses?

Some of the disadvantages are as follows: –

1) Data ware house can be costly due to high maintenance of the database. It is usually not static.
2) There is always a risk of it delivering outdated results which makes it less productive.
3) A fine line exists between data ware house and operational systems.

10) Explain about the bottom up design?

Bottom up design provides the advantage of a quick turnaround. As soon as the first data marts are created business values can be returned. Some of the disadvantages caused are due to multiple versions and false truth operations. Conforming dimensions and tight management can mitigate these risks.

11) State some of the benefits of data ware housing?

These are some of the benefits of data ware housing they are: –

1) Regardless of the data source it provides common data model this feature makes analysis of data much easier.
2) Inconsistency is identified during the loading process.
3) In case there is a crash of the database, database programmer can feel comfortable because it is stored in the data ware housing.4) It is very efficient and will not slow down the operational system.

12) What do you think about the future of data ware housing?

Data ware housing will be used by organizations to analyze their huge pool of data.With the development of various data ware house appliances performance of data ware housing applications can be improved. There would be many more apps working in accordance with the Gartner Group report which makes it much user friendly and reliable.

13) State two major differences between a data ware house and operational data ware house?

There exist two major differences they are: –
1) It integrates information from a pre existing source database
2) It is used for analysis usually for OLAP where huge amounts of data occur frequently.
5) Explain about the integrated data ware house stage?
At this stage data ware house gets updated every time a transaction occurs. The transactions performed during this time are passed back to the operational systems which records the transactions.
6)These are some of the questions make sure that you learn many more questions.