Frequently Asked Questions about IBM Informix Database Driver for Perl DBI ========================================================================== IBM Informix Database Driver for Perl DBI Version 2008.0513 (2008-05-13) -------------------------------------------------------------------------- WHAT IS THE DIFFERENCE BETWEEN IBM INFORMIX DATABASE DRIVER FOR PERL DBI AND DBD::INFORMIX? Spelling. The official product name had to be changed from DBD::Informix to IBM Informix Database Driver for Perl because the acronym DBD is a contested trademark of two other companies in the USA, so Informix could not release the product as DBD::Informix without potentially infringing on this trademark, and when IBM bought Informix (2001-07-01), the IBM name was prefixed to Informix products. Internally, Perl and DBI still uses the name DBD::Informix to access the driver, and much of the documentation still references DBD::Informix because that is how Perl references it, and because it is less of a mouthful than IBM Informix Database Driver for Perl DBI. -------------------------------------------------------------------------- HOW DO I REPORT TECHNICAL PROBLEMS WITH DBD::INFORMIX? See the information available via "perldoc DBD::Informix::TechSupport" and in the README file. -------------------------------------------------------------------------- WHY IS IBM INFORMIX ESQL/C A PRODUCT PREREQUISITE FOR DBD::INFORMIX? DBD::Informix is freely available software that is licensed on the same terms as Perl, under the GNU General Public License or the Perl Artistic License. However, to compile or use DBD::Informix, you need some IBM Informix software on your computer -- specifically, you need either IBM Informix ESQL/C or IBM Informix Client SDK. This provides a compiler and the supporting libraries necessary to connect to Informix databases. This software must be licenced from IBM. To purchase any IBM Informix software, look in the the IBM Informix Web site (http://www.ibm.com/software/data/informix), or contact your local IBM Sales Office. IBM Informix ClientSDK may be downloaded for some platforms from: http://www.ibm.com/software/data/informix/downloads.html -------------------------------------------------------------------------- WHERE CAN I FIND DOCUMENTATION FOR IBM INFORMIX PRODUCTS? You can download PDF files for most IBM Informix product manuals at the IBM Informix web-site: http://www.ibm.com/software/data/informix/pubs Electronic manuals are not available for some of the older product versions (but they are truly obsolete and should not be in use). --------------------------------------------------------------------------- WHICH VERSIONS OF ESQL/C AND CLIENT SDK ARE SUPPORTED? For details on which versions of ESQL/C and Client SDK are supported, consult the documentation: perldoc DBD::Informix::TechSupport -------------------------------------------------------------------------- WHICH OTHER VERSIONS OF IBM INFORMIX ESQL/C EXIST? Informix ESQL/C exists in versions 5.0x (obsolete), 5.1x, 5.2x, 6.0x (obsolete), 7.0x (obsolete), 7.1x (obsolete), 7.2x (obsolete), 8.0x (obsolete), 8.1x, and 9.x. Anything earlier than version 5.00 is very obsolete and cannot be used to build DBD::Informix. Within the 9.x family, the 9.0x, 9.1x, 9.2x and 9.30 versions are obsolete, and the other available versions are mostly part of Client SDK. Former Name Current Name ----------- ---------------------- ESQL/C 9.11 - ESQL/C 9.11 (obsolete) ESQL/C 9.12 - DevSDK 9.12 (obsolete) ESQL/C 9.13 - Client SDK 2.00 (obsolete) ESQL/C 9.14 - Client SDK 2.01 (obsolete) ESQL/C 9.15 - Client SDK 2.02 (obsolete) ESQL/C 9.16 - Client SDK 2.10 (obsolete) ESQL/C 9.20 - Client SDK 2.20 (obsolete) ESQL/C 9.21 - Client SDK 2.30 (obsolete) ESQL/C 9.30 - Client SDK 2.40 (obsolete) ESQL/C 9.40 - Client SDK 2.50 (obsolete) ESQL/C 9.50 - Client SDK 2.60 ESQL/C 9.51 - Client SDK 2.70 ESQL/C 9.52 - Client SDK 2.80 ESQL/C 9.53 - Client SDK 2.81 ESQL/C 2.90 - Client SDK 2.90 (Nov 2004) ESQL/C 3.00 - Client SDK 3.00 (Jul 2007) ESQL/C 3.50 - Client SDK 3.50 (May 2008) With the 7.3x servers, you would normally use Client SDK 2.80 or later. You should be planning to upgrade soon, too. With the 8.2x or later servers, you would normally use Client SDK 2.70 or later. If you have a 9.40 server, you would normally use Client SDK 2.70 or later; for IDS 10.00, you should use Client SDK 2.90 or later. For IDS 11.10, you should use Client SDK 3.00; for IDS 11.50, you should use Client SDK 3.50. Finally, note that Client SDK is available free of charge, so you should use it if at all possible. You can make Client SDK talk to the 7.x and even 5.x servers. --------------------------------------------------------------------------- WILL DBD::INFORMIX WORK WITH ANY OF THESE OTHER VERSIONS? It is believed that DBD::Informix will work with any version of ESQL/C from version 5.00.UC1 upwards. However, it has not been tested with every such version, and many of these versions are obsolete. For example, all the 5.0x versions are obsolete because they are not officially Y2K-compliant; ditto for the 6.0x, 7.0x and 7.1x versions. It has also not been tested on every platform. Note that there is some code in Makefile.PL which enforces 'this version is obsolete' rules on ESQL/C. You may need to remove that code - but it would be better to upgrade. --------------------------------------------------------------------------- DO I NEED AN IBM INFORMIX DATABASE SERVER ON MY DEVELOPMENT MACHINE? You do not need an IBM Informix database server on the computer where you build or use DBD::Informix. However, to compile DBD::Informix, or to make any meaningful use of it after it is compiled, you must have access to a computer with an IBM Informix database server installed and running on it. One step of the configuration process for DBD::Informix validates your IBM Informix ESQL/C and database environments and checks that you have access to at least one database. If this step fails, the makefile is not generated, so DBD::Informix cannot be compiled. If you do not have the IBM Informix database system set up already, you need to do so before you try to compile DBD::Informix. If you do not know how to do the setup, you must obtain the necessary training. IBM does provide training courses in such matters; consult the Web site or your local sales office as mentioned above. -------------------------------------------------------------------------- WHICH IBM INFORMIX DATABASE SERVERS ARE AVAILABLE? IBM Informix provides a large family of products, many of which are available in a number of versions. Database storage is managed by a program separate from user applications (such as Perl + DBI + DBD::Informix). Such a database management program is called the database server. The main Informix database servers are listed below. Refer to http://www.ibm.com/software/data/informix for additional product information. Informix Standard Engine (SE) 5.x and up Informix OnLine 5.x Informix OnLine Dynamic Server (ODS) 6.x or 7.x OnLine Informix OnLine Workgroup Server (WGS) 7.x versions, UNIX and NT Informix OnLine Workstation (OWS) 7.x versions, NT Informix OnLine Extended Parallel Server (XPS) 8.x OnLine Informix Universal Server (IUS) 9.x In 1998, Informix renamed the following products: Informix Dynamic Server (IDS) 7.3 Informix Dynamic Server with Universal Data Option (IDS/UDO) 9.1x Informix Dynamic Server with Advanced Decision Support Option (IDS/ADSO) 8.x Informix Dynamic Server with Extended Parallel Option (IDS/XPO) 8.x In July 1999, the new Informix Internet Foundation.2000 products were released and included: Informix Dynamic Server.2000 (IDS.2000) 9.2x Informix Internet Foundation.2000 (IIF.2000) 9.2x In 2001, the 2000 appellation was dropped. In 2004, the current version of IDS was 9.40. In 2005, the current version of IDS was 10.00. In 2007, the current version of IDS was 11.10. In 2008, the current version of IDS was 11.50. Version 9.2x merges the 7.x and 9.x code streams. Basically, Informix Dynamic Server.2000 is the direct upgrade path if you use Informix Dynamic Server 7.3x or an earlier version of IDS or OnLine. IDS.2000 is extensible but does not come with many extensions. IIF.2000 is the upgrade for IUS and comes with standard extensions. See the Informix Web site for details. In July 1999, Informix replaced the hyphen with a space in the name Informix-ESQL/C. So now the name is Informix ESQL/C. Older manuals will not be reissued just because of the spelling change. The acronym OWS is used only internally and might mean either the OnLine Workgroup Server or the OnLine Workstation products. Informix OnLine, ODS, OWS, and WGS are all known as OnLine. Although there are major differences between the various versions, these are not significant if you are not familiar with the Informix products. To use DBD::Informix, you need to have access to an Informix database server, which means that you need either OnLine, SE, or IUS on one of the computers in your network. DBD::Informix will probably be of no use to you unless you have access to a database. You must know the version number of the database server to ensure that you compile DBD::Informix with a compatible version of Informix ESQL/C and run it in a compatible runtime environment. Possible versions are 5.0x, (6.0x), 7.1x, 7.2x, (8.0x), 9.0x, or 9.1x, the x is a string such as '0.UC1' and yields a complete version string such as 7.22.UC2. Note that DBD::Informix does not work with Version 4.1x or earlier versions of the database servers. -------------------------------------------------------------------------- CAN DBD::INFORMIX BE COMPILED WITHOUT IBM INFORMIX ESQL/C? To compile DBD::Informix, you should have an IBM Informix ESQL/C compiler. If you built Perl with the same C compiler as the IBM Informix Classic 4GL c-code compiler uses, then you may be able to build DBD::Informix with a version 6.00 or later C4GL compiler. You would configure the build with the command: ESQL=c4gl perl Makefile.PL make make test This is not supported; it is not a good option and it should only be used as a last resort. The resulting executable code might be much larger than if you use a pure ESQL/C version. You cannot use IBM Informix 4GL Version 4.1x because it uses the ESQL/C Version 4.1x compiler, which does not provide the features that DBD::Informix needs. This compilation technique was shown to work in 1997 using DBD::Informix Version 0.56 (with Perl 5.004 and DBI Version 0.90) with IBM Informix 4GL 6.05.UC1 on a Sun Sparc 20 running Solaris 2.5.1. It was also shown to work in 2002 on a Sun UltraSparc running Solaris 7 with DBD::Informix 1.03.PC1, Perl 5.8.0, DBI 1.30, IBM Informix 4GL 7.31.UC3, with both Sun's WorkShop 6 update 2 C 5.3 2001/05/15 C compiler and with the GNU C Compiler (GCC) 3.1. Note that you should set the environment variable DBD_INFORMIX_ESQLCC_REMOVE_OPTIONS_REGEX to "^-KPIC$" to avoid warnings from GCC, and DBD_INFORMIX_ESQLLD_REMOVE_OPTIONS_REGEX to the same value to prevent linkage warnings. Note that Solaris is a simple environment to handle; other environments such as HP-UX are less easy. -------------------------------------------------------------------------- CAN DBD::INFORMIX RUN ON A COMPUTER DIFFERENT FROM WHERE IT WAS COMPILED? To run DBD::Informix only on the computer where you compiled it, you do not need any extra software, and you can skip the rest of this subsection. To run DBD::Informix on a different computer from where you compiled it, the other computer must have the same architecture as the computer used for compiling. However, the computers need not be identical; for example, code compiled on a Sun Sparc 20 can be run on a Sun Sparc 10. Every computer where you will use DBD::Informix must have either an IBM Informix ESQL/C development license, or an IBM Informix runtime license. Otherwise, you violate the terms of your license agreement with IBM (Informix). Either way, the license on the other computer should be the same version as the development license used to compile the software. (If you know enough about the compatability requirements for different versions of Informix products to argue about the finer points ignored by the "same version" criterion, you probably do not need to read this.) If you use a 5.x database server (OnLine or SE), you need an Informix ESQL/C RunTime license. If you will use a database on a remote computer, you will also need an Informix Net (or Informix Star) license. Note that OnLine 5.2x is distributed with Informix Star functionality. If you are using a 5.0x server, you should upgrade. In particular, using OnLine 5.0x is dangerous as the archives might not be restorable, which is not something you want to find out after the system has crashed and you need to restore it. If you use a 6.0x or 7.1x database server, you also need an Informix ESQL/C RunTime license. However, you do not need a separate license for remote database access because the remote database access technology is part of the basic product. If you use a 6.0x, 7.0x or 7.1x server, it is long past time to upgrade. If you use a 7.2x, 9.x or later database server, you need an Informix Connect license, and you do not need a separate license for remote database access because the remote database access technology is part of the basic product. If you use a 7.2x server earlier than 7.24, you should upgrade. If you use an 8.0x or 8.1x database server, you need either an Informix ESQL/C RunTime license or an Informix Connect license. The initial 8.00 version was released shortly after the 7.10 version was released, and the changes made in 7.20 for Informix Connect might not have been propagated to Version 8.0x. This has not been tested; you may have to extemporize to get DBD::Informix to work. If you are using an 8.0x or 8.1x server, you should upgrade. Further, both the DBI and DBD::Informix modules will need to be installed on the second machine, and should go into the same directory on both machines. That means that Perl must be installed in the same location on both machines. And unless you compiled DBD::Informix with the environment variable DBD_INFORMIX_RELOCATABLE_INFORMIXDIR set, you will need to have the Informix software installed in the same place on both machines. -------------------------------------------------------------------------- MY PROGRAM WORKS OK WHEN I RUN IT FROM THE COMMAND LINE BUT FAILS WHEN I RUN IT VIA A WEB SERVER (CGI, MOD_PERL, ETC), OR FROM A CRON JOB? The answer is the environment - almost invariably. You should establish exactly what the environment is when your script is run, using some surrogate for your real script that uses DBI and DBD::Informix. Then you will have to work out how to set the INFORMIXDIR, INFORMIXSERVER and LD_LIBRARY_PATH environment variables properly. With Apache, this is usually the SetEnv directive (possibly PassEnv instead). Other web servers will have equivalents. You could also consider trying to set the environment in a BEGIN block, but it may well set the environment too late to be useful. Note that DBD::Informix version 1.00 and later normally build the DBD::Informix shared library so that it references the Informix shared libraries with absolute pathnames. This should mean that the web server does not need to set LD_LIBRARY_PATH or the local equivalent environment variable. The configuration process records a default value for INFORMIXDIR and INFORMIXSERVER; these may be adequate for your production environment. Similar comments apply to jobs run by cron. Unlike jobs run with the 'at' command, cron jobs get only the most minimal environment set. You should ensure that the environment is set correctly by a script before it attempts to access DBD::Informix. -------------------------------------------------------------------------- IN THE FOLLOWING CODE, I GET ERROR -280 (A QUOTED STRING EXCEEDS 256 BYTES) WHEN THE VALUE OF $LONGCHARSTRING CONTAINS MORE THAN 256 CHARACTERS. THIS IS ODD BECAUSE LONGCHARCOL IS DEFINED TO CONTAIN MANY MORE THAN 256 CHARACTERS (EG CHAR(2500)). Please note that IDS version 9.30 and later and corresponding versions of ESQL/C do not impose this limitation. It could be time to upgrade. $sql = "INSERT INTO SomeTable(LongCharCol) VALUES('$longcharstring')"; my $sth = $dbh->prepare($sql) or die($DBI::errstr); $sth->execute() or dir($DBI::errstr) ESQL/C has an irritating limitation that the longest character string literal that it allows is 256 characters long. Furthermore, in most versions, you cannot embed newlines in string literals. There's a simple workaround which always works; use a place-holder in place of the string. This has the additional advantage of not breaking when the $longcharstring variable itself contains quote characters, whereas the example code will break. $sql = "INSERT INTO SomeTable(LongCharCol) VALUES(?)"; my $sth = $dbh->prepare($sql) or die($DBI::errstr); $sth->execute($longcharstring) or dir($DBI::errstr) Using placeholders is also the most reliable way to enter user defined data into the database (eg from a web page). If you take arbitrary data typed by the user, even using the $dbh->quote method, it may be possible for the user to break your system. In the original example, if $longcharstring contains: '); DELETE FROM SomeTable; DROP TABLE OtherTable; COMMIT WORK; and you run the command as written, then your database might be missing two (presumably important) tables. Ensure that the web user has the minimum possible privileges (CONNECT for the database, and no more than the minimum necessary table-level privileges on any table). -------------------------------------------------------------------------- WHEN I TRY TO BUILD THE SHARED LIBRARY, I GET AN ERROR MESSAGE ABOUT LOTS OF MISSING SYMBOLS LIKE PERL_NEWAV (REFERENCED IN DBDATTR.O) AND PERL_NEWSV (REFERENCED IN INFORMIX.O) AND MAIN. WHAT'S UP? This most frequently occurs when you need to modify the esql script to change the default compiler from cc to (typically) gcc, and you don't respect the INFORMIXC environment variable. At the start of the original esql script is a line that reads: CC=${INFORMIXC=cc} # Original version If you need to change that to use gcc by default, then modify it to keep the option of overriding the C compiler with the INFORMIXC environment variable, because DBD::Informix uses INFORMIXC to ensure that it can build the shared library on many systems (specifically, this is necessary on Solaris 2.6, Solaris 7 and Linux; it will be necessary on many SVR4-derived systems). CC=${INFORMIXC=gcc} # Correct change CC=${INFORMIXC=/usr/local/bin/gcc} # Correct change CC=gcc # Incorrect change CC=/usr/local/bin/gcc # Incorrect change Why? On these platforms, the -G option needs to be relayed to the C compiler or loader, but the esql script thinks that -G is an option intended for its own benefit. So, to get the -G option to the C compiler, it is set in the ESQLLD environment variable, and INFORMIXC is set to run the esqlld Perl script. If you modify esql to ignore INFORMIXC, you make it ignore a lot of hard work -- and cause the build to fail. See also the information about DBD_INFORMIX_ESQLCC_REMOVE_OPTIONS_REGEX and DBD_INFORMIX_ESQLLD_REMOVE_OPTIONS_REGEX in the file Notes/environment.variables. -------------------------------------------------------------------------- HOW CAN I UPDATE BLOBS You cannot update BYTE and TEXT blobs fully automatically with DBD::Informix. You can insert them; you can delete them; you can select them; all without paying very much attention to the issues. You cannot update them without using special measures. Technically, the DESCRIBE request must give DBD::Informix information about the types of the paramaters on the RHS of the SET clause in an UPDATE statement. Without that type information, DBD::Informix does not know that it needs to treat the parameter specially. [This should change in 2003 when IBM releases IBM Informix ClientSDK 2.81 - ESQL/C 9.53 - and IBM IDS 9.40, but the feature won't be available on older versions of the servers.] On the other hand, starting with version 1.03.PC1, you can update them. See the code in test file t/t73blobupd.t for an illustration of how to do it using the Informix type support with bind_param (and, one day, bind_param_inout). See also 'perldoc DBD::Informix'. -------------------------------------------------------------------------- WHEN I DO "perl makefile.PL" IT FAILS WITH ERROR -369. IT ALSO FAILS WITH THAT ERROR IF I TRY TO RUN esqlbasic. WHAT DOES IT MEAN AND WHAT MUST I DO TO FIX IT? Error -369 always means that the ESQL/C you are using is not installed correctly. Usually it means that: 1) although you copied off the distribution media, you did not run the installesql script. You need to provide a serial number (eg AAA#A123456) and an activation key (eg ABCDEF). Until you do this, the software will not let you use the libraries at runtime, even if you can compile with it. Or, 2) if you installed ESQL/C correctly, something else was subsequently installed incorrectly and wrote over one of the ESQL/C libraries. Either way, the corrective action is to reinstall either the ESQL/C product or the other product which overwrote the ESQL/C libraries. The other circumstance under which this can occur with ClientSDK 2.80 or later is if there is an internal error in the installation process. The licence number for such versions should be supplied automatically; if you get this error, then there is probably a bug in the installation code. -------------------------------------------------------------------------- HOW DO I CONFIGURE DBD::INFORMIX TO CONNECT TO A REMOTE DATABASE? How do you connect using DB-Access across the network? That's how you connect using DBD::Informix, too. For example, you will create an entry in your local sqlhosts file that references the remote system: remote_tcp oltlitcp remote service_name You will then simply do: $dbh = DBI->connect("dbi:Informix:dbase\@remote_tcp", "", "") or die "A horrible death!"; Note that if you also had a local database, you'd have an entry in the sqlhosts file such as: local_shm olipcshm local service_name And your connect statement will be: $dbh = DBI->connect("dbi:Informix:dbase\@local_shm", "", "") or die "A horrible death!"; Or, in other words, there is essentially no difference between the local and remote connections. If you need to specify username and password, do so in place of the empty strings. If you want to omit the '\@server' part, you can set $INFORMIXSERVER to the correct value. NB: The default value of $INFORMIXSQLHOSTS is $INFORMIXDIR/etc/sqlhosts. NB: On Linux in particular, you often need the FQDN (fully qualified domain name) of the server in place of 'local' or 'remote'. Usually, what 'uname -n' gives is what you need for the local machine. =========================================================================== Jonathan Leffler Informix Database Engineering, IBM Information Management @(#)$Id: FAQ,v 2008.1 2008/05/13 17:11:20 jleffler Exp $