In order to better visualize the relationships in a complex database, I'd like to create a graph/chart that shows the tables, and their relationships. Hibernate was used to create the database, and I have access to both the x.cfg.xml file and a Create schema.
Is there a tool that reads in SQL and creates a graph for visual analysis? Are there other means than drawing it by hand?
There is a tool I use sometimes called DbVisualizer which is very helpful for doing exactly what you're looking for. I've used it primarily with PostgreSQL but it's supposed to support most major databases.
If you're just looking for entity-relationship diagramming software that can reverse engineer an existing MYSQL database, give MySQL Workbench a look. The reverse engineering capabilities require the paid version but it's worth it with large databases.
I've actually enjoyed using the table visualizer in Microsoft SQL Server Enterprise Manager. You didn't specify what flavor of SQL you prefer, so I thought I'd mention it in case it might be useful.
For MySQL, I believe MySQL Workbench might be a useful tool.
If you are looking for a opensoure solution you may also take a look at DBDesigner from fabForce.net.
You can check this query tool, its still Beta so its free.
From the product's site : ..
Data tables are not always islands. Many times they relate to one another. Marie-Alix enables you to define relationships between tables, and then view the data accordingly...."
I've used TOAD to do this in the past, works great with Oracle and SQL Server. All sorts of visualization tools included, and one of the better sql client interfaces.