Database II final part 2 (chapter 9)

What is the difference between the first load and a refresh load

First load is the initial load which populated initially empty data warehouse tables Refresh load-every subsequent load

what is the purpose of data cleansing?

Data cleansing is used because it is common for data to have data quality problems.

briefly describe the transformation process

Transformation refers to the process of transforming the structure of extracted data in order to fit the structure of the target data warehouse model

briefly describe the extraction process

extraction refers to the retrieval of analytically useful data from the operational sources that will eventually be loaded into the data warehouse

What is the purpose of data warehouse/data mart front-end applications

can retrieve data from either from the data warehouse itself or from dependent data marts that contain a subset of the data from the data warehouse

Fact table attributes

contains foreign keys connecting it to the dimension tables and measures related to the subject of anaylsis

What is the difference between the relational and the multidimensional data base model?

main difference is in the method of locating the data. in relational model, a search has to take place in the fact table in order to locate a record multidimensional cube-every record can be looked up directly, eliminating the need for a search

What are the two main purposes of OLAP/Bi tools?

1. for arranged direct analysis of dimensionally modeled data 2. for the creation of front-end applications

Briefly describe the load process

Load refers to the process of loading the extracted, transformed, and quality assured data into the target data warehouses

what is the difference between OLAP and OLIP?

Online transaction processing, updating, modifying, deleting, querying, and presenting data from databases for operational purposes Online analytical processing (OLAP)- refers to querying and presenting data from data warehouses and/or data marts for analytical purposes

Briefly describe the data warehouse deployment process

alpha release, beta release, production release

What are the three basic OLAP/BI tool features?

Slice and dice-operation adds, replaces, or eliminates specified dimension attributes from others Pivot(rotate)-operation does not change the values displayed in the origninal query, it simply reorganizes them Drill down and drill up-drill down is to make the granularity of the data is query result finer, and drill up means make it coarser

What is an executive dashboard?

executive dashboard is intended for use by higher-level decision makers within an organiztion

How is database management software used in the process of creating a data warehouse?

using CREATE to create data warehouse tables, populate the data warehouse with the appropriate relevant data retrieved from the operational databases.