Question

• SQ1. What is a data warehouse (DWH)? Why does an organization need both operational DB and DWH (analytical DB)?
• SQ2. What are the differences between a data mart and a DWH? What are the differences between an independent data mart and a dependent data mart?
• SQ3. What are the four core components of a data warehousing system? How are they different from the main components of an operational database system?
• SQ4. What are the two functional differences between operational data and analytical data? How are they related to the data makeup differences and the technical differences between the two types of data?

Answer 1

answer-

SQ1. What is a data warehouse (DWH)? Why does an organization need both operational DB and DWH (analytical DB)?

A data warehouse is an information system which stores historical and commutative data from single or multiple sources. It is designed to analyze, report, integrate transaction data from different sources .

organization need both operational DB and DWH so that using operational database it can provide security of data and its access . Database act as an efficient handler to balance the requirement of multiple applications using the same data while DWH helps organization users to access critical data from some sources all in one place. It provides consistent information on various cross-functional activities .

SQ2. What are the differences between a data mart and a DWH? What are the differences between an independent data mart and a dependent data mart?

The vital difference between a data warehouse and a data mart is that a data warehouse is a database that stores information-oriented to satisfy decision-making requests whereas data mart is complete logical subsets of an entire data warehouse.

In simple words, a data mart is a data warehouse limited in scope and whose data can be obtained through summarizing and selecting the data from the data warehouse or with the help of distinct extract, transform and load processes from source data system.

The data is stored in a single, centralised repository in a data warehouse. As against, data mart stores data decentrally in the user area.

The construction of data warehouse involves top-down approach. Conversely, while constructing a data mart the bottom-up approach is used.

differences between an independent data mart and a dependent data mart -

The main difference between dependent and independent data marts is that the dependent data marts get data from an already created data warehouse while the independent data marts get data directly from an operational source and/or external source.

A dependent data mart obtains data from a data warehouse. It improves data centralization. Furthermore, if it is necessary to develop one or more physical data marts, it is possible to configure them as dependent data marts.

An independent data mart does not get data from the central or the main data warehouse. Therefore, an independent data mart does not have any association with the main data warehouse or other data marts. Hence, storing and performing analytics on each data mart is a separate task. Mostly, this data mart type is suitable for small groups or sections within an organization.

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