ERwin/ERX first hit the streets in 1989 and has not hit the brakes since. Logic Works has not blinked and has managed to keep its product in the forefront of database modeling tools.
Installation is painless; you simply feed in four diskettes and you're set. After you have ERwin/ERX installed, you face the infamous blank page. Yes, it's time to begin your database model. Fortunately, ERwin/ERX surrounds you with the tools you need to develop your model quickly. You will notice a floating toolbox that lets you click and create independent and dependent entities, edit attributes of entities, specify subtype relationships, and create identifying, non-identifying, and non-specific relationships.
Above your model is a toolbar with buttons for DB Sync, connect to database, changing the target server, and subject area editor. The most useful are the buttons for switching between entity level, attribute level, entity definition, and physical schema level. After you click on the toolbox and select the Independent Entity icon tool, you simply click on the blank page to create your first entity. Next, you right-click on the entity to bring up a selection of editors (so as to be able to define the attributes, and so on). You can also have a pulldown menu for the editor selection. I found it initially confusing to be forced to right-click on each entity to select the editor I needed to use. Simply click on Option-Preference-Show Editor Menu and Show Display Menu. Now two additional pulldown menus appear at the top of your screen that have the options available when you right-click on an entity.
Inside the product are several bells and whistles that make life easier. For instance, you can use the GoTo option to jump quickly to a particular entity in your data model. After pulling up GoTo, you can scroll down in the list of entity objects after you type in the first letter of the entity. GoTo can either jump to the entity (by default) or open the entity editor on the selected entity. This type of control is icing on the cake: It makes a repetitive task such as making changes to attributes of entities a lot easier.
ERwin/ERX is able to have multiple models open at the same time, making it simple to copy and paste between models thanks to the MDI support. I found the new On-Diagramming feature very useful. You can click on and directly edit an object in the Diagram window, which makes changing the relationships and attributes much easier.
I was able to toggle my diagrams between IDEF1X (Integration DEFinition for Information Modeling) notation and IE (Information Engineering) notation. IE support is a new feature with this version of ERwin/ERX. The IDEF1X support can be crucial if you are working on a federal process reengineering project.
One truly great feature is the ability to bring chaos to order by reverse-engineering databases. ERwin/ERX can reverse-engineer tables, foreign-key declarations, and indexes, and it can infer primary keys and relationships, but not triggers, which ERwin can generate. This feature can be a godsend if you are working on a messy database that lacks modeling information, or if you are converting from one database system (such as Ingres) to another (such as Microsoft SQL Server). You have a tremendous selection of target servers to choose from, including Informix 7, DB2, Rdb 6, Teradata, Progress, Sybase System 11 and 10, Oracle7, Microsoft SQL Server 6 and 4.2, IBM OS/400, SQLBase, Ingres, NetWare SQL, and several desktop databases including Clipper, FoxPro, dBASE III, dBASE IV, Access, and Paradox.
You can use ERwin/ERX to create indexes, triggers, and stored procedures and to define business rules. It has a full-blown reporting tool that lets you create reports on entities, attributes, relationships, constraints, and subject areas and either print them or send them off to a DDE server application or to another Windows application. If you have multiple individuals working on the data model, then you will need to use a third-party version control software, in this case Intersolv's PVCS (version 5.1 or later). PVCS support is tightly integrated with the menu structure of ERwin, becoming another option on the "Save As" menu. However, Logic Works is banking on many developers migrating over to their new ModelMart product (formerly known as AOS). This CASE workgroup tool provides version control, central model management with conflict management, and the ability to merge models. Also bundled inside ModelMart are a few bells and whistles such as a read-only model viewer called ERwin Navigator that you can give to all of your pesky programmers who want to peek at the existing data model without messing with it. Just remember that additional copies of Navigator cost $795 each, while ModelMart starts at around $19,995 for 10 ERwin/ERX users and up to 20 Navigator users. You need a ModelMart-enabled version of ERwin to use the two products together (it costs the same as the normal version of ERwin).
Some larger models can start looking like the Los Angeles freeway system after 50 or so tables. The lines are often so criss-crossed that you cannot make out exactly what is going on. ERwin/ERX has a useful feature that lets you drag lines exactly where you want them to go, helping you get a clear picture of relationships.
I hate a dry "feature only" manual. Fortunately, the manual that comes with ERwin/ERX is detailed and provides background material on both the how and the why of database design. Overall, the manual is a nice teaching tool and the online help is complete.
While I like doing as much as possible on the screen, I find that I get a lot more accomplished in my design when I print it out and walk through it. Therefore, any features that help in the printing area score high in my book. ERwin/ERX 2.5 has a number of new printing niceties. Things such as headers and footers become very useful with sub-models. Print preview makes it easy to spot tables that may overlap pages prior to printing everything and finding it out after the fact. The new print scaling makes printout resizing a snap. If you are like me, your database designs can grow and grow and, before you know it, they can exceed the total print size allowed by your modeling product. ERwin/ERX has addressed this potential problem by accommodating a page grid of up to 18 by 12 pages, allowing database model printouts of a whopping 140 square feet! Features such as these help distinguish a mature product from a newcomer. (See Figure 1.)
No Undo! It's hard to comprehend that there is not any undo support. We all make mistakes and would like to undo what we just did. Come on, guys! ERwin/ERX still suffers as a 16-bit product. A 32-bit version is slated for revision 2.6, so you can finally use your 32-bit ODBC drivers, and it should be shipping about the time you read this review, but you will still not find any long file name support. Version 2.6 will, however, enable you to compare or update your model against the database or to generate delta alter scripts of any changes that have been made.
Undo support can be achieved by adding the ERwin ModelMart workgroup tool, but I still think it should be a part of the basic package. Modifying tables with cascading referential constraints is always tricky. ERwin provides a minimal solution by allowing you to group the associated tables in a subset; ERwin will drop the entire subset in reverse referential order. With a little work, ERwin could automate this process and figure out referential relationships itself without forcing users to manually group tables into subsets.
I always check if a vendor has a forum on CompuServe. Nothing annoys me more then banging my head against the wall with a problem and not being able to throw the problem out to other users and get real feedback rather then a sanitized reply from technical support. Fortunately, Logic Works (GO LOGICWORKS) has its own support forums on CompuServe.
Some CompuServe forums can be intimidating: a couple of users verbally taking the head off a new user just for posting an innocent question. At the other extreme is a forum that is as stiff as a cadaver. I found Logic Works' forum to be an active site with a number of ERwin/ERX users sharing tips and an overall friendly spirit.
Technical support is an often overlooked cost that can sneak up on you and take a hefty bite out of your budget. Logic Works ERwin/ERX includes 45 days of free technical support. After that period, you must pay $560 for one year, which includes phone support and upgrades. I bugged the technical support folks at Logic Works on several occasions and they always answered promptly, were very helpful, and put up with all of my questions.
ERwin/ERX stands among several other key products from Logic Works, including BPwin for business process modeling and specialized flavors of ERwin for PowerBuilder, SQL Windows, and Visual Basic. I hate redoing models, so I think its MSP Migrator for ERwin is useful because it can read in your legacy CASE and then export it into an ERwin format, saving you a lot of valuable time.
I have barely scratched the surface of all of the features in ERwin/ERX. There is not enough room to explain how ERwin/ERX lets you attach pre-generation and post-generation scripts to tables. Suffice it to say, you do not run out of features in this product. ERwin/ERX is an outstanding choice as a data-modeling tool. It is understandable that it has won numerous readers' choice awards from DBMS and other database magazines.
