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

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. ¶
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 across 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.