We run Solarwinds Orion network management product. It uses a straightforward SQL database.
We need to pull NodeID, NodeCaption, and Comments from the 'Nodes' table and do the following:
1) Create a new table for 'Comments'. This will contain Node ID, a date/time field, and a 'Comments' field.
2) Populate a pulldown box with the NodeCaption; the identifier will be NodeID. User will select a given node and click a 'submit' button (or use Autopostback), which will then fill (3) below with the relevant info, selected from the comments table using 'NodeID'.
3) Use some sort of 'gridview' type view to display all current comments (if any) from the 'Comments' table for the selected Node.
4) A textbox will allow users to add comments. A second submit button (if not using autopostback for the initial node selection) will then add the entered text to the 'Comments table, along with the NodeID of the selected Node, and the current date/time.
That's it. Just a form to select a node, to see all current comments about it, and to add a new comment.
If possible, it'd be useful in the 'comments' gridview to have a checkbox next to each comment. If you tick the box(es), those comments will be deleted when you hit the submit button (while also uploading any new comment you have.
Please contact me if you have questions!