What a data model actually is

A data model is a CONTRACT between a query and every template that will ever read it. That sentence is the whole lesson, and it is why its shape matters more than its content. Concretely, a data model is one or more data sets — usually SQL — arranged into a structure with names. The template does not see your query. It sees the STRUCTURE the query produced: a group called G_INVOICE containing an element called INVOICE_NUMBER. Every field placed in every template binds to those names. SO CHANGING THE MODEL LATER BREAKS THINGS YOU HAVE FORGOTTEN ABOUT. Rename an element and every template referencing it renders blank — not an error, a blank space where a supplier's invoice number used to be. Move an element between groups and the loops stop finding it. The report still runs and still produces a document, which is what makes this the most…

In this module: Module 4 · BI Publisher: data models, templates and bursting

1. 1What a data model actually isFree preview
2. 2SQL data sets: writing the query
3. 3Parameters and lists of values
4. 4Bursting: one run, many recipients
5. 5RTF templates: the practical subset
6. 6Excel and eText templates
7. 7Sub-templates and reuse
8. 8Layout, pagination and the printed page
9. 9Localisation: Arabic, dates and numbers
10. 10Performance: making a slow report fast
11. 11Security in BI Publisher
12. 12Scheduling and delivery
13. 13What breaks: five BI Publisher failures
14. 14Lab briefing · A supplier statement, end to end