Dimension

Enhanced Definition

In the context of data warehousing and business intelligence on IBM z/OS, a dimension is a structural component that categorizes and describes data in a fact table, providing context for analytical queries. It represents a perspective or attribute along which business data can be analyzed, answering the "who, what, where, when, why" of a business event.

Key Characteristics

- Hierarchical Structure: Dimensions often contain attributes organized into natural hierarchies (e.g., Time dimension: Year > Quarter > Month > Day; Product dimension: Category > Subcategory > Product).
- Descriptive Attributes: They consist of descriptive attributes that provide meaningful context for the measures in fact tables (e.g., Customer Name, Product Description, Geographic Region).
- Surrogate Keys: Typically employs a unique, system-generated integer key (surrogate key) as its primary key, which is then used to join to fact tables, insulating the data warehouse from changes in operational source system keys.
- Slowly Changing Dimensions (SCD): Strategies (Type 1, Type 2, Type 3) are implemented to handle changes in dimension attributes over time, preserving or updating historical context as required.
- Conformed Dimensions: Dimensions that are shared and consistently defined across multiple fact tables or data marts, ensuring consistent analysis across different business processes.

Use Cases

- Sales Analysis: Analyzing sales figures (facts) by Product, Customer, Time, or Geography dimensions to identify trends and performance.
- Financial Reporting: Aggregating financial data (e.g., revenue, expenses) by Account, Department, or Fiscal Period dimensions for budgeting and compliance.
- Supply Chain Optimization: Tracking inventory levels and movement by Supplier, Warehouse, or Product dimensions to improve efficiency.
- Customer Relationship Management (CRM): Segmenting customers and analyzing their behavior based on Demographic, Purchase History, or Interaction dimensions.
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