Check out the database diagram tool written for Chrome and the HTML 5 canvas. It generates scripts for a database schema based on the diagrams you set up. It's only a proof of concept, but it's fun to play with. http://diagrams.seaquail.net/
a third option developed using lessons learned from microformats and RDFa, and designed to be integrated into HTML5 itself: microdata.
“Adding microdata” to your page is a matter of adding a few attributes to the HTML elements you already have.
So where is the real information? It’s in the <dd> element, so that’s where we need to put the itemprop attribute. Which property is it? It’s the name property. Where is the property value? It’s the text within the <dd> element. Does that need to be marked up? the HTML5 microdata data model says no, <dd> elements have no special processing, so the property value is just the text within the element.
This technique is also useful for microdata. There are two distinct pieces of information here: a title and an affiliation. If you wrap each piece in a dummy <span> element, you can declare that each <span> is a separate microdata property.
There are two major classes of applications that consume HTML, and by extension, HTML5 microdata:
Web browsers
Search engines
Google supports microdata as part of their Rich Snippets program.
a handy tool to see how Google “sees” your microdata properties
Just like associating a URL with a Person, you can associate a URL with an Organization. This could be the company’s home page, a contact page, product page, or anything else. If it’s a URL about, from, or belonging to the Organization, mark it up with an itemprop="url" attribute.
To handle edge cases like this, HTML5 provides a way to annotate invisible data. This technique should only be used as a last resort. If there is a way to display or render the data you care about, you should do so. Invisible data that only machines can read tends to “go stale” quickly. That is, someone will come along later and update the visible text but forget to update the invisible data. This happens more often than you think, and it will happen to you too.
itemscope says that this element is the enclosing element for a microdata item with its own vocabulary (given in the itemtype attribute). All the properties within this element are properties of http://data-vocabulary.org/Geo, not the surrounding http://data-vocabulary.org/Organization.