You could probably use something like Visio to draw boxes and lines, especially for conceptual, very high-level things. But when you're getting down to the database level, where you're building a design and you're creating DDL out of it, or you're going in the other direction where you're reaching into system catalogs and bringing things back, that starts to really require specialization. Visio isn't going to reverse-engineer that for you. Those features in erwin are valuable. In addition, erwin has versioning so you can keep versions, over time, of those models and you can compare any version to any version. If you're looking at a specific database and you want to see what changed over time, that's really useful. You can go back to a different version or connect that to your change-control processes so you can see what was released when. With versioning, you can also compare between development environments and production environments. You can see what may not have actually changed or what changes are in the works. It also enables you to do the kind of troubleshooting where you're looking at: Why on this server does this copy of something seem to behave differently than on that server? erwin highlights that really quickly for you. You don't have to closely eyeball your comparison. erwin creates a report that comes back and says what is different. And you can focus on almost anything, from the privileges in the catalog to a data type or a name anomaly. Even for servers that are case-sensitive in their structure, it will tell you the difference between something in all-caps and something that's mixed-case. If you're getting to that level of detail when you're troubleshooting, erwin is great at doing that sort of thing. In terms of the solution's visual data models for helping to overcome data source complexity, erwin shows you "what is," if you're talking about the physical layer. When it comes to being able to make things clearer and more understandable, it depends on what your structure is. If you've just reverse-engineered SAP, it's abbreviated German. You may need other tools to help you understand it. If you're doing forward work — if you're going from conceptual to logical to physical — erwin is fabulous at letting you change what you see in the graphic. You can change your data model from just looking at primary keys to looking at primary keys and foreign keys, to looking at just the definition of the table in boxes. It allows you to change that visualization depending on your audience. If you're working with the DBAs, you can add metadata and it expands the box showing the visual of the table structure, so you can concentrate on just data types, or you can do data types and nullability and foreign keys, and all different sorts of things. You can do the indexes on top of it as well. You could end up with a table graphic that's the width of your screen if you've added all the details in. And if it's too hard to look at that way — if you're trying, for instance, to make sure that EmpID Is always a varchar 250 — it also has the ability to take that graphic and move it into what's called the Bulk Editor. That looks much more like an Excel spreadsheet, within a view in your erwin model. You can sort your Excel spreadsheet by column name and see all of the details next to it. That way, everywhere EmpID shows up in that model, it is now in more of a column-row view, and you can easily look at that to make sure that all the EmpIDs say varchar 250. If you see one that's wrong, you can actually change it in the Bulk Editor and it changes it in the graphic automatically, because an erwin model really isn't a graphic, it's much more like a little Access database. So when you change it on one view, it fixes it in the other. In addition, anybody using erwin to do forward engineering will find the solution's ability to compare and synchronize data sources with data models, in terms of the speed of keeping them in sync, to be almost instantaneous. You can connect an erwin data model to a database and deploy your changes, or you can deploy just delta changes. Or you can deploy one little piece because you've identified one little piece of your model. But most of comparing and synchronizing data sources with data models comes down to people and process. The tool will absolutely help you get there, but it's not going to take on all of the requirements of putting standards and processes in place. If you haven't tied your erwin Data Modeler to your change-control, it can't help you. So it's not a dynamic connection to your servers, it's just a tool that you can use with your environments. Also, while I'm not configuring erwin, I do have templates that erwin lets me set up to configure models: different templates do colors and domains and prebuilt macros for definitions, based on different things. You don't have to configure erwin. You just have to tell it what sort of a platform you're either going to or coming from. You can also set up some draw templates and customize the colorization of different things. If you want all your primary keys to be red, you can configure that, and set that up as a template. Finally, the solution's code generation ensures accurate engineering of data sources. With reverse-engineering, I have found it to be completely accurate. I've never found a time when it didn't get the source information correctly into the model. If you're doing a data warehousing project, where you're going from source to target, erwin can produce an extremely comfortable and dependable and trusted graphic of where you're coming from, while you design where you're going to. You know what the data types are, what the nullability is — the structure of the data. You don't know all the characterizations of data values because erwin is not profiling data values. It's just picking up the catalog structure of the tables. But it is completely trustworthy, once you've reverse-engineered it. It has never let me down along those lines.
