beginner's question
Date: 1999/12/02
Message-ID: <3846A1FE.B27718EB_at_nervana.montana.edu>#1/1
For any schema where any table can (somehow) be connected
to any other table through a connected path of
primary_key/foreign pairs, it must be possible for an
external parsing routine to read the data dictionary and
construct a connected, directional graph of the entire
schema.
Given this, and also given an arbitrary collection of GUI
query screens, where each widget in the query screen can be
toggled on or off, and where each widget in the query screen
is associated with a (tablename, column_name, data_type)
touple, then it must be (is it?) possible for that external
parsing routine to read the "widget state" of the screen
and dynamically construct the "foreign_key=primary_key"
clauses needed to make a logical select statement.
In other words, any query screen that interactively prompts
for the "SELECT columns" part of a select statement as well
as the "WHERE constraints" part of the select statement, the
only hard part left is to add in the "link this table to
that table" clauses. The programmer who designed the schema
can do this. But what about a parsing routine that only
knows the state of the query screen?
--
/* Sandy Pittendrigh >--oO0>
* http://nervana.montana.edu/~sandy
* sandy_at_nervana.montana.edu
*/
Received on Thu Dec 02 1999 - 00:00:00 CET