DW - Data Warehousing & Modeling

Dimensional hierarchy

A dimensional hierarchy denotes how data is organized at various levels of aggregation. An analyst uses a dimensional hierarchy to identify various trends at one level, drill down to lower levels to detect causes for these trends, and roll up to higher levels to see the effects the trends have on the whole business.


This is the process of converting normalized tables again into a de-normalized form. Here, a table may contain redundant information. This is a common technique within data warehousing where star schemas are used to optimize performance. Denormalizing a database consumes more space and slows OLTP performance but improves query performance in a BI environment.

Data quality

Data quality pertains to aspects such as availability, completeness, accuracy, consistency, relevance and timeliness of data. High data quality is essential to business intelligence’s role as a means of decisional support. 

Poor data quality examples: missing fields, old or inaccurate information, data conflicts, inaccessible data in legacy systems.

Data mapping

Data mapping is a process of defining a link between two distinct data models. It is used in software engineering to describe ideal ways to represent and access any form of information. It is used in data warehousing by linking source data models to target data models and additional for describing any transformations between these two models.

Change data capture (CDC)

Change data capture (CDC) is the process of capturing changes made at the data source and applying them throughout the enterprise. CDC minimizes the resources required for ETL (extract, transform, load) processes because it only deals with data changes. The goal of CDC is to ensure data synchronicity.

Data scientist

A data scientist is a job title for an employee or business intelligence (BI) consultant who excels at analyzing data, particularly large amounts of data, to help a business gain a competitive edge. To do so, the employee is using statistical & data mining techniques.

Data Mashup

A data mashup is the integration of heterogeneous digital data from multiple sources for business purposes.

Data Latency

Data latency, in a data warehouse context, is the time between the creation of data in a source system and the exact time at which the same data is available for end users on the business intelligence platform.

Role-based security

A role-based security is a user-level security feature that allows you to restrict access to a certain feature in the system based on the user role.

In a reporting system, a role-based security layer will enable you to assign roles for each user by allowing or restricting them from performing certain tasks.


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