RE: Logical File or OPNQRYF or any other way ? - Legacy

Hi, Dave - back again!

So you say a flat file is equivalent to first normal form. That is not what 
I've seen elsewhere. Webopedia 
http://www.webopedia.com/TERM/F/flat_file_database.html has this definition:

A relatively simple database system in which each database is contained in a 
single table. In contrast, relational database systems can use multiple tables 
to store information, and each table can have a different record format. 

Very basic, I know. Elsewhere I saw a discussion on this, where an example of a 
flat file looked like what you see if you read through a multiple-format 
logical file - some fields (or extent of bytes) were the same but the rest was 
a coin toss. That is more my idea of a flat file - some identifying set of 
bytes tells you what kind of information is in the record, but otherwise it is 
a free-for-all. 

(This is even done in stuff from IBM. Have you looked at the output file for 
the database monitor - ironically, it is a monitor for SQL only! There is a 
record ID, and different columns have differeing meanings, dependent on this 
record ID. This is NOT my idea of a good time. There is also a join field 
explicitly called, to help in self joins, IIRC. Now there are Redbooks or 
Redpapers that give examples of extracting information from this mess, and 
Centerfield Technology, my former employer, has products that convert this data 
into some level of normalization.)

Are you saying that you canNOT create a first normal form in Oracle? But you 
can on the iSeries? That a "true" relational database will force third or 
higher normal form?

I must be missing something here - it seems we are not talking about exactly 
the same thing - maybe you are talking physical structure (as Date speaks of) 
versus the application level. I don't know yet.

Thanks
Vern
-------------- Original message -------------- 

> Charles & Rob, 
> 
> 
---snip---

> 
> So let's bring things somewhat full circle: My definition of the 
> legacy iSeries file structures being flat (1st normal form) when 
> compared to such structures as true relational, or IMS or the like, is 
> correct. I'll certainly accept someone's change of my definition that 
> most files for most applications built on the iSeries files are 
> non-relational. 
> 
>