CMS CMS and Database Questions
 

Just trying to get an idea of how this CMS works.

Looking at the database* in the cms_node table* what are these nodeleft* noderight* and nodeparent items?

Also* what is the contenttypeid? Where does this content ID come from? For example* a thread or post promoted to an article seems to take on the contenttypeid of 18. What are some of the other contenttypeid's that I am likely to see in there* besides 17 which I assume is a section contentypeid.

In addition* when looking at the cms_article table I noticed that some of the entries have something within previewtext while others do not. Why is this* all threads were promoted the same way with the same settings?

Thanks in advance!