Data Warehouse Concepts

Data Warehouse – 

A data warehouse is a subject oriented integrated time variant and nonvolatile collection of data in support of management decision-making process.

Data Warehousing – 

Data warehousing is the process of constructing and using the data warehouse. The major processes involved are data cleaning, data integration, and data consolidation.

Data Mart –

A data mart is the subset of a data warehouse that’s of value to a specific group of users and catering to a specific subject area of the business.

Data Cube –

A data cube allows data to be modeled and viewed in multiple dimensions. it’s defined by dimensions and facts.

Dimensions-

Dimensions are the perspectives or entities with respect to which an organization wants to keep records. for example time, item, product, location etc are the dimensions of sales.

Facts – 

Facts are numeric measures. they are the quantities by which we want to analyze the relationship between dimensions. The quantity of sales, Sales Amount etc.

Start Schema –

The most common modeling paradigm for a data warehouse, in which the model contains a large central fact table and all dimension tables are directly linked to the fact table.

Snowflake Schema –

The snowflake schema is a variant of the star schema model where some dimension table is normalized, thereby splitting the data into additional dimension tables.

Fact Constellation –

A collection of stars in which multiple fact tables share same dimension tables.

Hierarchy-

A sequence of mappings from a set of low-level concepts to higher level more general concepts. Day >> Week >> month >> quarter >> Year

Roll-up-

The roll-up operation performs aggregation on a data cube, either by climbing up a dimension hierarchy or dimension reduction.

Drill Down-

The reverse of roll-up. it navigates from less detailed data to more detailed data.

Slice-

The slice operation performs a selection on one dimension of the given cube, resulting in a subcube.

Dice-

The dice operation defines a subcube by performing a selection on two or more dimensions.

Pivot-

Pivot is a visualization operation that rotates the data axes in views to provide an alternate data presentation.

Drill through- 

Navigating to the detailed data from the bottom levels.

 

 

 

 

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