Re: Is File Record Format Level ID the only way to determine if twofiles are identical?

You're killing me Chuck :). Thanks for the info. I sure didn't know
that changing from a field Alpha to Zone will not cause the Format ID.



"CRPence" <CRPbottle@xxxxxxxxx> wrote in message
news:<mailman.2046.1232575364.21608.rpg400-l@xxxxxxxxxxxx>...

Lim Hock-Chai wrote:

Is File Record Format Level ID the only way to determine if
format of two files are identical? If so, can someone point
me to a api that I can use to retrieve the
Record Format Level ID of a file?

The only valid comparison for "identical" is to either confirm that

the format is shared by the other file, or to extract & then compare

all

of the specific format & field attributes for which "identical" can be

inferred. There is an API to list record formats [and sharers] for a
file, plus the DSPDBR command.

The Record Format Level Identifier is merely a hash, which can
conveniently be used to _infer_ that the attributes of a given format
does *not* match a prior extracted LvlId from the [functionally] same
file. The opposite can not be inferred, so each attribute of interest

must be verified, for a matching hash. As a hash, it is impossible to

infer definitively that two identical hash values are indicative of

two

identical formats. It is possible that several distinct formats

[across

the hashed attributes] will generate the same hash value; and in fact,

the change of a field data type between Alpha and Zoned, without a
change in its length, is likely to generate the same FmtLvlId. It is
the responsibility of the developer to ensure the changed format has
also generated a new [hash] level.

Yes, IO buffer comparison is all I needed. I was hopping that there

is

a file in QSYS2 or a field in INFDS that can tell me if io buffer of

two

different files are the same. I guess there is no such thing.

Well, I

have no choice but go for the api.

The system database cross-reference file QADBIFLD in QSYS [and its
logicals, e.g. SYSCOLUMNS in QSYS2] have a variety of field

attributes.

If those attributes are sufficient to determine "identical" for

your

purposes, then any exception to the join [or ordered line comparison]

of

the field attributes of two files can verify the format of each file
does not match the other. One specific attribute that I know is not
available [but should not be relevant for I/O buffer] is the

"allocated

length" of a VARCHAR.

Regards, Chuck