--- vladimir konrad <vk@xxxxxxxxxxxxx> wrote: > I think that I understand basic relational theory but then I had an > idea. > Basically, instead of adding field to a table every time there is a > need for it, have a table split in two: one holds identity (id) and > one holds the attributes (linked to this id). > Basically, if in the future user decides that the subject should > have a new attribute, he can simply add "attribute definition" and > attribute_definition_set (if any) and the application would handle Basically, you would be creating your own data dictionary (i.e. system catalog) on top of the db data dictionary. The database already comes with a way to easily add columns: ddl. I have seen newbie database designers reinvent this method a hundred times. The performance hits and complexity of querying data would far out weigh any perceived maintenance gain. My .02. LewisC Lewis R Cunningham An Expert's Guide to Oracle Technology http://blogs.ittoolbox.com/oracle/guide/ LewisC's Random Thoughts http://lewiscsrandomthoughts.blogspot.com/ ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
