Is it known who "invented" materialized path approach in modeling
hierarchical data with SQL?

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Can anyone tell me who is "Peter Chen"and all his writings. Thanks

I am reading the following:
In a functional dependency X --> Y
the value of Y is *determined* by the X component.
and the value of X uniquely determines the value of Y.

I'd like to hear thoughts on what books, in your opinion, are true
classics in the field of software engineering. I read a lot on the
topic - at least a book a month for many years. There are many good
authors, however, the only book on making software that is truly

Many of my customers indicates that they want to switch to MySQL etc. in a
near future. And since MySQL (among others) doesn't support Triggers, the
idea of having triggers to maintain hierarchical data becomes a problem.
The article on "Maintaining Hierarchies" by Itzik

Or should I title it "question to Jan?"
Could standard definition
FORANY t1,t2 t1.x=t2.x -->
EXISTS t3,t4 t3.x=t4.x=t2.x & t3.y=t1.y & t3.z=t2.z & t4.y = t2.y &

What's the difference, if any, between managing a database and managing the
data contained in a database.
In terms of people's roles and responsibilities,  what are the advantages of
having the same person responsible for managing the database and the data in

I wonder if anyone can tell me the name of the general case of a particular
operation.  I have not seen it discussed here in my lurking.
I first saw the operation in the Allocation process of an ERP package, but
the problem is easy enough to generalize.  The particular thing about ...

I'm confused by the term "relational completeness."
As near as I can tell, someone (Codd?) came up with
a set of operations on relations, and said they were complete,
because they were just as expressive as the relational calculus,

I have 3 tables: TUsers, TUserGroups, TUserGroupMembers. Now I want to
create a new table TPermissions which needs to contain information about
what a user or a usergroup has permissions for in my application. To that
end I'm thinking something like:

In this discussion, I'm trying to compare two very different reasons for
using a DBMS.  I'm calling them the "integrated data store" (IDS) and the
"encapsulated data store" (EDS).  What I think I've seen is that people who
build an IDS and people who build an EDS use the same tools ...

A table T contains list of items and their common properties.
Some of those items in the list also have additional
properties. Let's say that there are 3 groups of items
- group 'a' doesn't have any additional properties, group

A few years ago,  I was at a client site, dealing with the BANNER
application.  BANNER manages a wide variety of administrative data for a
university.  BANNER has a huge number of little tiny reference tables one
for each different code type.  I don't remember the exact number,  but ...

   I have fair knowledge of B-tree and hash indexing mechanisms. What
data structure/algorithms should I read upon if I want to create indexes
on multiple keys of a same relation? For e.g if a Employee relation has
EmpNo, EmpName, EmpSalary, EmpDepth attributes & users can query ...