Mysql Database structure

[A10]

I need to know about the database structure used by testlink. I understand that testlink has classes which can populate themselves with data from the database. I'm interested in information about the database structure

So far I've gathered test projects, test suites, and test cases are organized inside of a tree. Node positions are stored in nodes_hierarchy. nodes_hierarchy.id is an id to a particular table depending on nodes_hierarchy.node_type_id.

Which table are test cases stored in? Is it tcversions?

What is stored in testplan_tcversions? Why does user_assignments.feature_id hold an id for the testplan_tcversions table?

If I wanted to retrieve all information about a particular test case, what tables in the database would I need to query?

If I wanted to retrieve all information about a particular test suite what tables would I need to query?

The executions table has a column for tcversion_id. Is the tcversion_id an id for a test case in the tcversions table? Do I need to know more than a tcversion_id to get all information about a particular test case?

And one final question that's not about database structure. The Assigned column in the overview section on the General Test Metrics page (/lib/results/resultsGeneral.php) seems to be way off. I can get the numbers it gets if I query for count(distinct( user_assignments.id )) where build_id = a particular build we're interested. Should that page instead be querying for distinct feature_id s?

Thanks for reading this far. Would you mind answering some of my questions?

[Unhandled]

Maybe this could help you?
http://mantis.testlink.org/view.php?id=4004