The 12 Rules of OLAP

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The 12 Rules of OLAP

E. F. Codd, father of the relational database, and his associates have produced a white paper listing the 12 rules for OLAP (on-line analytical processing) systems. The list is fundamentally a formula for a successful information system, whether you call it an EIS, a DSS, or a business information system. For more information on the white paper, call Arbor Software, Santa Clara, CA, (408) 727-5800.


 1. Multidimensional conceptual view. This supports EIS "slice-and-dice"
    operations and is usually required in financial modeling.
 2. Transparency. OLAP systems should be part of an open system that
    supports heterogeneous data sources. Furthermore, the end user should
    not have to be concerned about the details of data access or conversions.
 3. Accessibility. The OLAP should present the
 user with a single
    logical schema of the data.
 4. Consistent reporting performance. Performance should not degrade
    as the number of dimensions in the model increases.
 5. Client/server architecture. Requirement for open, modular systems.
 6. Generic dimensionality. Not limited to 3-D and not biased toward
    any particular dimension. A function applied to one dimension
    should also be able to be applied to another.
 7. Dynamic sparse-matrix handling. Related both to the idea of nulls
    in relational databases and to the notion of compressing large files,
    a sparse matrix is one in which not every cell contains data. OLAP
    systems should accommodate varying storage and data-handling options.
 8. Multiuser support. OLAP systems, like EISes, need to support
    multiple concurrent users, including their individual views or
    slices of a common database.
 9. Unrestricted cross-dimensional operations. Similar to rule 6; all
    dimensions are created equal, and operations ac
ross data dimensions
    do not restrict relationships between cells.
10. Intuitive data manipulation. Ideally, users shouldn't have to use
    menus or perform complex multiple-step operations when an intuitive
    drag-and-drop action will do.
11. Flexible reporting. Save a tree. Users should be able to print just
    what they need, and any changes to the underlying financial model
    should be automatically reflected in reports.
12. Unlimited dimensional and aggregation levels. A serious tool
    should support at least 15, and preferably 20, dimensions.