AW: Tables and PFs

[Buck <kc2hiz@xxxxxxxxx>]

Birgitta Hauser wrote:
> There is a nice article about the differences between DDS described physical
> and logical files and SQL Defined Tables, Views and Indexes:
>
> Modernizing Database Access
> The Madness Behind the Methods
> By Dan Cruikshank
> http://www-03.ibm.com/systems/resources/systems_i_software_db2_pdf_Performance_DDS_SQL.pdf

That's a nice link Birgitta, thank you.  Somehow I missed it when it
came out in January 2006.  I'm sure it must seem to you that you repeat
yourself endlessly, but those repetitions can always help a new person...

I was a bit doubtful that an SQL table always validated on the write, so
I did a small experiment.

CREATE TABLE buck/ddl (nbr DECIMAL(9,0) NOT NULL DEFAULT 0,txt
char(50) not null )
ovrdbf dds ddl
call ddsddl
Data mapping error on member DDL.
C
I/O error CPF5029 was detected in file DDS.

Application error.  RNX1299 unmonitored by DDSDDL at statement
  0000000015, instruction X'0000'.


The RPG program is simple too:
 * test data validation for DDS files vs DDL files
fdds       uf a f   55        disk

idds       aa  01
i                                  1    5  nbr
i                                  6   55  txt

c                   eval      nbr = '$bad$'
c                   eval      txt = '$bad$'
c                   except    writedds
c                   eval      *inlr = *on

odds       eadd         writedds
o                       nbr                  5
o                       txt                 55

For completeness, I also ran the program over a DDS-defined file:
     A          R DDSR
     A            NBR            9P 0
     A            TXT           50A

and it runs without error.

Very much something to think about.
Viel danke.
  --buck