Creating Cubes in Multidimensional Modeling
This document outlines the process of creating and configuring cubes within SQL Server Analysis Services (SSAS) using multidimensional modeling techniques. Cubes are fundamental to dimensional modeling, providing a multidimensional view of data for analysis and reporting.
Steps to Create a Cube
You can create a cube using SQL Server Data Tools (SSDT) or directly through Management Studio, though SSDT is the primary tool for development.
Using SQL Server Data Tools (SSDT)
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Open your Analysis Services project in SSDT.
If you don't have a project, create a new one of type "Analysis Services Project".
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Add a new Cube.
Right-click on the "Cubes" folder in Solution Explorer and select "New Cube...". This will launch the Cube Wizard.
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Choose a creation method.
You can choose to create a cube from existing tables in your data source view (recommended for most scenarios) or create a blank cube to define manually.
- From existing tables: The wizard will guide you through selecting fact tables and related dimension tables.
- From existing dimension/measure groups: If you've already defined these, you can use them.
- Blank Cube: For advanced users who want to build from scratch.
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Define the Fact Table and Dimensions.
If you chose "From existing tables", select your primary fact table. The wizard will then suggest related tables as dimensions. Review and confirm these relationships.
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Select Measures.
Choose the columns from your fact table that you want to expose as measures. You can also define aggregation functions (SUM, COUNT, AVG, etc.).
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Name the Cube and Cube Fields.
Provide a meaningful name for your cube and its associated measure groups, dimensions, and hierarchies.
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Complete the Wizard.
Review the summary and click "Finish" to create the cube structure.
Configuring the Cube (After Wizard)
Once the cube is created, you can further configure it in the Cube Designer:
- Browser Tab: Allows you to preview the cube data with sample queries.
- Dimensions Tab: Manage the dimensions that are part of the cube. You can add or remove dimensions, define hierarchies, and set attribute properties.
- Measures Tab: Define new measures, modify existing ones, and set aggregation behaviors.
- Calculations Tab: Create calculated members, tuples, and sets using MDX (Multidimensional Expressions) for advanced analytical scenarios.
- Slicers Tab: Define default filters or slicers that apply to the cube.
- Perspectives Tab: Create logical subsets of the cube for specific user groups or reporting needs.
- Actions Tab: Define actions that can be performed on cube data, such as drilling through to detail data.
- Mining Structures Tab: Link data mining models to the cube.
Best Practices for Cube Creation
- Descriptive Naming: Use clear and consistent names for cubes, dimensions, measures, and hierarchies.
- Appropriate Aggregations: Choose the correct aggregation functions for your measures to ensure performance and accuracy.
- Dimension Design: Ensure your dimensions are well-structured with clear hierarchies.
- Performance Tuning: Consider cube partitioning, aggregation design, and caching strategies for optimal performance.
- Security: Implement roles and permissions to control access to cube data.