Perry Spiller wrote:
Drew et al
I can see that the discussion has left me behind, somewhat.
I became baffled at a certain point in following Drew's
"whatever" and gave up in favour of other things. But I was
left with one significant impression.
Before I detail that, let me say that I have, with commercial
s/ware, used (created) flatfile databases in the past - the
distant past. But none in more recent times - like, 15 years.
The first thing that struck me was the terminology. I'm
familiar with file, record, field, indexed and non-indexed
(i.e. searchable) , exporting data and so on.
When I opened Drew's Tutorial, I was struck by a range of
unfamiliar terms.
A database table is a collection of records. Each record contains
individual pieces of data called fields. The SQL 92 standard introduces
the terms catalog and schema, which refer to the organization of data in
database systems. Fields are contained in records, records are contained
in tables, tables are contained in schemas, and schemas are contained in
catalogs. Finally, all of the elements are stored in a database. A
schema is also likely to contain views, aliases, indexes, triggers, and
structured types.
Table 11. Simplistic database definitions
Term Simplistic Definition
Field Individual piece of data such as a first name, or date.
Record Collection of related fields, treated as a single unit; a record
is a single row of fields.
Table Collection of records.
Schema Collection of tables, views, aliases, indexes, triggers, and
structured types. Frequently used to mean the structure of a group of
tables.
Catalog Collection of schemas.
Database Encapsulates all of the items, including catalogs, schemas,
tables, records, and fields.
Many database systems do not support catalogs or schemas, especially
smaller database systems. Larger database systems are more likely to
support catalogs and schemas, but the names and precise definitions
differ between different database systems. For example, in some systems
a table is called a catalog and in others a table is called a schema—the
different usages were in place before the SQL92 standard provided a
common definition.
All of these are complicated by the fact that the atual definition is
different depending on the database vendor.... Even so, the word Schema
is used to mean a few different things.
--
Andrew Pitonyak
My Macro Document: http://www.pitonyak.org/AndrewMacro.odt
My Book: http://www.hentzenwerke.com/catalog/oome.htm
Info: http://www.pitonyak.org/oo.php
See Also: http://documentation.openoffice.org/HOW_TO/index.html
