Masterful data modeling

Despite what some people may think, data modeling is still the preferred method for creating database schemas. Unfortunately, modeling often gets pushed to the back burner in lieu of creating tables and relationships in the middle of coding the application. For those who would push data modeling to the front burner if only they had a better tool, there’s Embarcadero’s smooth and easy ER/Studio. Version 7.1 adds a number of exciting new features.

You can run ER/Studio either as a stand-alone client or connected to a central repository. The repository allows you to create a centralized database to house your models and apply security to control who can alter models and define enterprise-level data dictionaries for use in all models. The repository doesn’t yet allow access to sub-models without also allowing access to the main model, and it’s hampered by other minor shortcomings as well. Embarcadero, however, says it is working to enhance the functionality soon.

Easy imports
Reverse engineering an existing model is not only easy, it also comes with some attractive options. Usually when you import an existing model you have to spend a lot of time arranging the tables in some kind of meaningful format before you can even begin working; on really large models I’ve seen this process take as long as three days. Using ER/Studio you can reformat your models with a single click into one of seven model designs -- including circular, hierarchical, orthogonal, symmetric, and tree -- and you have plenty of options to control how each layout behaves. You can define handling options for both connected and disconnected entities including, but not limited to, node and edge spacing, staggering, and space between nodes.

You can also easily organize subject areas by defining any number of sub-models or using colored shapes to highlight different subject areas. For example, you could place all of the customer tables in a yellow circle, the distribution tables in a green box, and the billing tables in an orange pentagon. The colors work well for smaller models, but for larger models where you have hundreds of entities to fit on the screen, you will need to define sub-models for each logical section. Sub-models provide a very efficient way to view only those entities you want to see.

Capacity planning
ER/Studio boasts a new capacity planning feature that will help architects project disk requirements on the production system. For each table you can count the number of rows that are currently held. In the capacity-planning screen you can define many options for sizing your physical model including initial size, maximum size, growth rate, index usage, row overheads, and much more. After you fill in the required data, you can generate a report showing projected database growth over time. This is an extremely useful function that often goes overlooked in even the biggest enterprise development scenarios. One little extra I’d like to see added would be the capability to specify expansion percentages. Say a child table is always 25 percent larger than its parent. It would be nice to simply specify the growth of the parent table, and have its children taken care of automatically without needing to do the math.