IDS Forum

Re: Length of Blob Column

Posted By: Andreas Legner
Date: Tuesday, 24 January 2017, at 5:29 a.m.

In Response To: Re: Length of Blob Column (DAVID GROVE)

Hi David,

I just came over=20
http://www.ibm.com/support/knowledgecenter/SSGU8G=5F12.1.0/com.ibm.dbext.do=
c/ids=5Fr0055115.htm=20
-> GETLENGTH() function.

You'd get to this through the excompat blade bundled with the server:

dbaccess <your=5Fdatabase> <<!
execute function sysbldprepare("excompat.1.0", "create");
!

-> real function name seems to be dbms=5Flob=5Fgetlength() which is defined=
=20
for blob and clob arguments.

Seems to do just what you wanted, and all bundled, obviously since=20
11.70.xC5 (might be able to just copy this blade to an older version=20
even?).

Second point:
the length of an sblob is not and cannot be known to the row "containing"=20
the sblob (should rather read "pointing to") as, by nature of sblobs, the=20
sblob is not owned by the row (can be pointed to by zero to many rows -=20
but nobody really owns it, and it doesn't have any notion of who/what is=20
pointing to it). You'd always be able to modify any sblob, so any length=20
information within a row having an sblob field would never be reliable.
As a consequence of this any attempt to determine any attribute of an=20
sblob, e.g. its length, would have to open the real blob ... which can be =

costly in larger queries, esp. when having this somewhere down in a=20
complex where clause.

HTH,
Andreas

From: "DAVID GROVE" <david.grove@alaska.gov>
To: ids@iiug.org
Date: 19.01.2017 18:58
Subject: Re: Length of Blob Column [38519]
Sent by: ids-bounces@iiug.org

Informix 12.10=20
Solaris 10 (SPARC)=20

The issue of someone needing to have a LENGTH() or SIZE() function that=20
applies to sblobs has come up irregularly, but repeatedly, in this forum=20
since=20
at least 2006. I have participated in many of those discussions. I, and=20
others, have made requests, over the years, for IBM to provide this=20
functionality-- just like they do for CHAR data types. And blobs. But, not =

sblobs.=20

At least one person with IBM connections has acknowledged that this has=20
been=20
requested for a long time, and stated that it would be forthcoming. To=20
date,=20
nada.=20

Anyway, Mr. Nunes has helpfully posted this link a few times, in the past: =

http://www.ibm.com/developerworks/data/zones/informix/library/techarticle/d=
b=5Fsblob.html=20

It really is helpful-- it provides some kit and info to aid in "rolling=20
your=20
own" LENGTH function.=20

Now, I find myself, again needing this functionality and information. I=20
have=20
used the information in the article above, successfully, years ago. But, I =

no=20
longer have it.=20

I recently attempted to download that article again, so I could use its=20
valuable content to create (actually, I think it contained a binary=20
version=20
for SPARC Solaris) a new blade to provide the needed functionality. That=20
is,=20
to create a blade to implement a LENGTH() function for sblobs.=20

The link above is dead. Does anyone know where that article, or comparable =

information, might currently reside? IBM declined to provide needed=20
functionality, but did provide (unsupported) resources to enable a=20
customer to=20
build his own. But, now, even that seems to be non-existent.=20

If it is no longer necessary because IBM has now implemented some form of=20
LENGTH() function for sblobs in IDS, I would be happy to learn of it. Our=20
version 12.10FC3 still doesn't have it.=20

If that material is "out there", and anyone knows where it is, please let=20
me=20
know.=20

I did note that, in one or two past threads on this topic, someone asked=20
why=20
this capability is needed. I would say for the same reason that one might=20
want=20
to retrieve (or use in WHERE clause) the LENGTH of a CHAR.=20

Thank you.=20

DG=20

***************************************************************************=
****=20

Forum Note: Use "Reply" to post a response in the discussion forum.=20

Messages In This Thread

• Length of Blob Column
  MARY ANNA SINGER -- Thursday, 25 February 2010, at 4:04 p.m.
  • Re: Length of Blob Column
    Fernando Nunes -- Thursday, 25 February 2010, at 6:02 p.m.
    • Re: Length of Blob Column
      Fernando Nunes -- Friday, 26 February 2010, at 9:18 a.m.
    • Re: Length of Blob Column
      DAVID GROVE -- Thursday, 19 January 2017, at 12:57 p.m.
      • Re: Length of Blob Column
        DAVID GROVE -- Thursday, 19 January 2017, at 1:03 p.m.
        • Re: Length of Blob Column
          Paul Watson -- Thursday, 19 January 2017, at 1:14 p.m.
          • Re: Length of Blob Column
            DAVID GROVE -- Thursday, 19 January 2017, at 3:22 p.m.
            • Re: Length of Blob Column
              Paul Watson -- Thursday, 19 January 2017, at 3:27 p.m.
      • Re: Length of Blob Column
        Paul Watson -- Thursday, 19 January 2017, at 1:09 p.m.
      • Re: Length of Blob Column
        DAVID GROVE -- Thursday, 19 January 2017, at 6:06 p.m.
      • Re: Length of Blob Column: A Solution
        DAVID GROVE -- Monday, 23 January 2017, at 5:45 p.m.
      • Re: Length of Blob Column
        Andreas Legner -- Tuesday, 24 January 2017, at 5:29 a.m.
        • Re: Length of Blob Column
          DAVID GROVE -- Tuesday, 24 January 2017, at 7:34 p.m.
          • Re: Length of Blob Column
            Paul Watson -- Tuesday, 24 January 2017, at 8:01 p.m.
            • Re: Length of Blob Column
              DAVID GROVE -- Tuesday, 24 January 2017, at 8:31 p.m.
              • Re: Length of Blob Column
                DAVID GROVE -- Wednesday, 25 January 2017, at 7:23 p.m.
                • Re: Length of Blob Column
                  Paul Watson -- Wednesday, 25 January 2017, at 7:27 p.m.
                • Re: Length of Blob Column
                  John Miller iii -- Thursday, 26 January 2017, at 1:30 a.m.

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