nationavon
MIS
Is there a maximum size for scalars in perl. Is there a buffer size I can set? I am having trouble when I do a sql select with the Oracle DBI if the string is too long.
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Scalars
- Thread starter nationavon
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luckydexte
Programmer
nationavon,
This is straight from my Perl book:
The longest string fills all of your available memory (although you wouldn't be able to do much with that). This is in accordance with the principle of "no built-in limits" that Perl follows at every opportunity.
Brandon
This is straight from my Perl book:
The longest string fills all of your available memory (although you wouldn't be able to do much with that). This is in accordance with the principle of "no built-in limits" that Perl follows at every opportunity.
Brandon
- Thread starter
- #3
nationavon
MIS
From reading that it sounds like my problem lies with the DBI Oracle module.
How long is the string you're trying to read? If it's longer than 200 or so, you may need to set an option to tell the interface you need longer strings. I don't know about Oracle, but in MySQL if you want to read a string (or glob) longer than 200 you need this statement:
Tracy Dryden
tracy@bydisn.com
Meddle not in the affairs of dragons,
For you are crunchy, and good with mustard.
Code:
$dbh->{'LongReadLen'} = 1024;Tracy Dryden
tracy@bydisn.com
Meddle not in the affairs of dragons,
For you are crunchy, and good with mustard.
What is the Oracle column type of the long string field?
Hardy Merrill
Mission Critical Linux, Inc.
Hardy Merrill
Mission Critical Linux, Inc.
"Programming the Perl DBI" by Descartes and Bunce has a section towards the back that describes each of the databases - the Oracle section describes
String data handling
VARCHAR2(size) - limit 2000 bytes for Oracle 7, and 4000 bytes for Oracle 8
CHAR - limit 2000 bytes
RAW - limit 2000 bytes
LONG/BLOB data handling
LONG - can hold up to 2 GB
LOB - can hold up to 4 GB
FILE - can hold up to 4 GB
The book on p. 141-142 says
"LongReadLen typically defaults to 0 or a small value
like 80, which means that little or no LONG data will
be fetched at all. If you plan to fetch any LONG
datatypes, you should set LongReadLen within your
application to slightly more then the length of the
longest column you expect to fetch. Setting it too
high just wastes memory."
Read the perldocs for DBI on LongReadLen - on *nix, do
perldoc DBI
and search(using the slash "/"
for "LongReadLen" - there's a lot of great info in there to help you.
HTH.
Hardy Merrill
Mission Critical Linux, Inc.
String data handling
VARCHAR2(size) - limit 2000 bytes for Oracle 7, and 4000 bytes for Oracle 8
CHAR - limit 2000 bytes
RAW - limit 2000 bytes
LONG/BLOB data handling
LONG - can hold up to 2 GB
LOB - can hold up to 4 GB
FILE - can hold up to 4 GB
The book on p. 141-142 says
"LongReadLen typically defaults to 0 or a small value
like 80, which means that little or no LONG data will
be fetched at all. If you plan to fetch any LONG
datatypes, you should set LongReadLen within your
application to slightly more then the length of the
longest column you expect to fetch. Setting it too
high just wastes memory."
Read the perldocs for DBI on LongReadLen - on *nix, do
perldoc DBI
and search(using the slash "/"
for "LongReadLen" - there's a lot of great info in there to help you.HTH.
Hardy Merrill
Mission Critical Linux, Inc.
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