RE: Level Check Question (jt)

["jt" <jt@xxxxxx>]

Been meaning to get back to this-un, also.

There's no direct connection between specifying field-level DDS in LF and
using a Field Reference file.  Just that shops that like the one approach
probably like the other.  (Moot point if you have code-generators doing
both, of course.)

Afaik, field level described LF won't cause any level checks (unless
changed).

| -----Original Message-----
| From: midrange-l-bounces@xxxxxxxxxxxx
| [mailto:midrange-l-bounces@xxxxxxxxxxxx]On Behalf Of Tom Liotta
| Sent: Friday, March 12, 2004 10:23 PM
| To: midrange-l@xxxxxxxxxxxx
| Subject: RE: Level Check Question (jt)
|
|
| midrange-l-request@xxxxxxxxxxxx wrote:
|
| >   9. RE: Level Check Question (jt) (jt)
| >
| >| Isn't this a practical side-effect of DDS LFs anyway? As long as
| >| (1) the LF _explicitly_ lists fields and (2) programs use the LF
| >| to access the data, there should be no problems if new fields are
| >| added to the PF nor if the fields are rearranged in the PF. (It
| >| doesn't matter if fields are added at the end, in the middle
| or wherever.)
| >
| >That's correct, and was the standard in the first 38 shop I worked in
| >(Liebert in '82).  There are other benefits as well, such as
| making it more
| >convenient to do multi-format LF and join LF.  However afaik, most shops
| >doing this would normally have the added overhead of an organized and
| >maintained central FldRef file or "Data Dictionary".
|
| I don't see the connection to a 'FldRef' file. Why would this
| come into it at all (other than that it might be a good idea regardless)?
|
|
| >| Programs using old LFs shouldn't need to be recompiled although
| >| the old LFs themselves do (though I'm not clear why they _have_
| >| to be other than that's the way DB2/400 was written.)
| >
| >I don't think they do need recompiled if they use old LFs with the fields
| >specified explicitly... ?  Also, the main reason I switched to
| ChgPF is that
| >it's my (partial) understanding IBM does some pointer switching to avoid
| >rebuilding the access paths (unless necessary).
|
| Yes, the explicit LFs were the ones I was meaning when I said
| "old LFs", i.e., ones that were effectively unchanged even if
| recompiled. Also, I agree about CHGPF... a great tool -- helps
| avoid numerous LF re-compiles _especially_ explicit LFs and
| related *pgms. Implicit LFs though can still get formet level Id
| changes after CHGPF and lead to need for *pgm recompiles.
| Possibly explicit LFs as well; I just haven't run into them.
|
| Tom Liotta