README for DBD::Informix -- an Informix interface for Perl 5 using DBI.

  Portions Copyright (c) 1994-96 Alligator Descartes
  Portions Copyright (c) 1996-99 Jonathan Leffler

  You may distribute under the terms of either the GNU General Public
  License or the Artistic License, as specified in the Perl README file.

---------------------------------------------------------------------------

PREREQUISITES

   You need the following 5 items to build DBD::Informix successfully:

   1.  Perl 5.004 or later.
   2.  DBI 1.13 or later.
   3.  A C compiler which accepts function prototypes (eg GCC 2.95.2).
   4.  Informix ESQL/C 5.00 or later, or ClientSDK 2.00 or later.
   5.  A 'stores' database to which you can connect without specifying
       username or password, and in which you can create tables.  Ideally,
       the connection should not use shared memory (not olipcshm nor
       onipcshm), and you should have DBA privileges in the database.

   The default build steps are:

       perl Makefile.PL
       make
       make test
       make install

   If you aren't sure about any of these items, or if one of the build
   steps above fails when you run it, you need to read the information
   below.  The section 'BUILD AND TEST ENVIRONMENT' will help you set your
   environment variables.  If you run into problems during the build or
   test phases, read the section 'IF YOU HAVE PROBLEMS BUILDING
   DBD::INFORMIX'.

   When you have DBD::Informix working *and* installed, please use 'sh
   ItWorks' to report your successful installation.  Please check the
   output file It-Worked (especially the email address it deduces), and
   send it to the maintainers in an email with the subject "DBD::Informix
   - It Works":

           [email protected]
           [email protected]

PERL

   If you do not have Perl version 5.004 or later, then build, test and
   install it before doing anything else!  You should be using at least
   Perl version 5.004_04 and really should be using Perl 5.005_03.  Please
   ensure that you compile it with whatever options are necessary to make
   the C compiler accept prototypes; the DBD::Informix code uses
   prototypes (almost) everywhere.  You are also strongly encouraged to
   use the C compiler to create shared libraries, even if the Perl
   configuration script suggests that you use the 'ld' program directly.
   There have been endless problems for people who do not use the C
   compiler to create the shared libraries, and very few for those who do.

   Also note that to install DBD::Informix, you must be able to put files
   under the Perl lib directory.  See the file Notes/nonroot.install for
   alternative options.

DBI

   If you do not have DBI version 1.13 or later installed, then build,
   test and install it.  Although some old versions of DBD::Informix
   allowed you to use older versions of DBI than the version it was built
   with, the current versions do not.

   Note that if the 'perl Makefile.PL' process requires a later version of
   DBI, it means that there's a minor bug in these notes -- use the
   version it says.  Also note that "perl -MCPAN -e 'install Bundle::DBI'"
   will get the latest version.  Similarly, if it rejects your version of
   Perl, it means you should upgrade your Perl.

C COMPILER

   To build DBD::Informix, the C compiler must accept function prototypes.
   This is not a problem on any machine to which Informix is currently
   ported (though the HP-UX bundled compiler does not accept prototypes at
   all, and the ANSI compiler does not accept them unless told to do so).
   If you have problems, get hold of the GNU C Compiler v2.95.2 or later.
   It is available from http://egcs.cygnus.com.  You should use the same
   compiler to build Perl and DBI and DBD::Informix.  Note that Perl 5.005
   requires a C compiler which handles prototypes.

ESQL/C OR CLIENTSDK

   You must have a version of Informix ESQL/C or Informix ClientSDK
   installed on the machine where you wish to compile DBD::Informix.
   Informix Connect is not sufficient.  The Notes/Informix.Licence file
   contains more information about what you need.  ESQL/C Versions 4.1x
   and earlier are not (and will not be) supported by DBD::Informix.
   ESQL/C Versions 5.00 upwards should be OK.  If you do not have ESQL/C
   and are not prepared to buy it, then please don't try to use
   DBD::Informix; it won't work.  You can probably get Informix ClientSDK
   at a reasonable cost.  If you have Informix ODBC drivers available to
   you, consider using DBD::ODBC instead.  If you are on Linux, you should
   investigate the software available from the main Informix web site:

                        http://www.informix.com/
                      http://www.informix.com/idn

   You must also be able to compile, link and run ESQL/C programs with
   your setup.  The Makefile.PL will test that you can do this, but it
   will save you time if you ensure this before hand.  If you cannot
   compile and link free-standing ESQL/C programs, you certainly won't be
   able to hook DBD::Informix into Perl.  If you need help with
   environment variable settings, then consult the information below, and
   also the file Notes/environment.variables.

                             *** BEWARE ***

   DBD::Informix version 0.61 has been tested on Informix Universal Server
   version 9.14.UC4 (on a Sparc 20 running Solaris 2.6).  Where the IUS
   database uses the same types as were available in earlier versions of
   Informix products, there doesn't seem to be any problem.  However, it
   is known to fail badly (sometimes with an assert firing and a core
   dump, but sometimes with an error such as -402 'Address of a host
   variable is NULL' or a verbose message about an unrecognized data type
   being treated as a null value) if it encounters one of the IUS-specific
   data types.  IUS is also now known as Informix Dynamic Server Universal
   Data Option, or IDS-UDO.

   The pre-IUS data types which are known to work are the following, plus
   their various synonyms:
       SMALLINT, INTEGER, SERIAL
       DATE, DATETIME, INTERVAL
       SMALLFLOAT, FLOAT, DECIMAL, MONEY
       CHAR, VARCHAR (NCHAR, NVARCHAR)
       BYTE, TEXT

   The IUS-specific data types which probably work are:
       BOOLEAN, INTEGER8, SERIAL8, LVARCHAR

   The IUS-specific data types which probably do not work include:
       BLOB, CLOB
       Any user-defined type
       ROW types
       Collection types (SET, LIST, MULTISET)

   Handling the other types is more complex; they represent the antithesis
   of Perl's untyped variables.

   As an example of the problems, the IUS SysProcedures table in the
   system catalog has a ParamTypes column of the type RtnParamTypes, and
   therefore DBD::Informix will not work if you try to select all the
   columns from this table.  There are probably other columns in the
   system catalog for which this is true.  And there may be other tables
   which won't work for the same reason.

                        *** YOU WERE WARNED ***

   DBD::Informix has been tested with some version 8.x (OnLine XPS, now
   known as Informix Dynamic Server Extended Parallel Option or IDS-XPO)
   versions of ESQL/C and databases.  There may still be some problems,
   but...

                 *** YOU WERE WARNED ABOUT THIS TOO ***

   DBD::Informix will compile under ClientSDK 2.01.UC1 (ESQL/C 9.14.UC1),
   but some tests will fail.  This appears to be a bug in this version of
   ClientSDK.  Working with the same code under ClientSDK 2.02.UC2 (ESQL/C
   9.15.UC2) and 2.10.UC1 (ESQL/C 9.16.UC1), the failures in t/t31nulls.t
   and t/t32nulls.t now pass.

                *** YOU WERE ALSO WARNED ABOUT THIS ***

   Most versions of ESQL/C which support shared libraries have shared
   linking as the default behaviour, which is correct.  Other versions
   reportedly have static linking as the default behaviour, which is a
   pain in the posterior.  The Makefile.PL will add the '-shared' flag to
   the ESQL/C command line to try to force shared libraries for ESQL/C
   versions 7.20 and upwards.  If this does not work for you, or if you
   are building a static Perl, you will need to set the environment
   variable DBD_INFORMIX_ESQLC_LINKAGE either to nothing if your version
   of ESQL/C does not support the '-shared' option at all, or to '-static'
   to force static linkage.  You could also use this environment variable
   to bootstrap any special ESQL/C compiler options into the build process
   (eg '-thread' if you are experimenting with threaded Perl and threaded
   ESQL/C); you are advised to set '-static' or '-shared' as well.

                *** YOU WERE ALSO WARNED ABOUT THIS ***

STORES DATABASE

   Unless you have a 'stores' database that you can connect to without
   specifying a username or password (and in which you can create tables),
   you will need to set various environment variables to tell the build
   and test code for DBD::Informix which database to use for testing and
   exactly how to connect to it.  For more details on the environment
   variables which can be set, see the section BUILD AND TEST ENVIRONMENT.

   You *must* have a fully working Informix environment before you try to
   build and test DBD::Informix.  This means you need to have access to at
   least one database where you have at least RESOURCE level privileges.
   If you don't understand what this means, read the "Informix Guide to
   SQL: Syntax" manual, and especially the GRANT section.  You can obtain
   a PDF version of any Informix documentation from:

                    http://www.informix.com/answers

   If you don't have RESOURCE (preferably DBA) privileges on a database,
   you should consider creating a database called 'stores' for testing.
   If you do not have DBA privileges, the test t/t55mdata.t will fail.
   Unless you have other problems, you can disregard this failure.

   Note that DBD::Informix testing creates and drops its own tables.  Most
   of the tests use temporary tables.  It doesn't matter whether the test
   database has a database logging or not, though a logged database allows
   more features to be tested than an unlogged database.  You can use a
   brand new, empty database for testing.  When DBD::Informix creates any
   database object, the name begins with "dbd_ix_".  If the test t99clean
   runs, there should be nothing left over from the testing (please report
   any such debris).  DBD::Informix has one test which creates a database
   and then drops it.

SHARED MEMORY CONNECTIONS

   The multiple connection tests use two databases for preference (though
   the tests will use the same database twice if you do not specify two
   separate databases).  As of version 0.95, the esqltest program will
   report that both connections use shared memory and will allow you to
   proceed after writing a message.  The actual test scripts attempt to
   detect that the two connections both use shared memory connections and
   skip the tests.  However, if you run into problems with shared memory
   connections (for example, error -27000 from the esqltest program), then
   read Notes/olipcshm.  If your databases are not on the machine where
   you are building DBD::Informix, you will need to ensure that you have
   the necessary privileges to connect to the machine where the databases
   are.  This may be as simple as setting DBD_INFORMIX_USERNAME and
   DBD_INFORMIX_PASSWORD (see below); it may be require you to get your
   systems administrators to set you up with a login account on the
   machine.

BUILD AND TEST ENVIRONMENT

   Please ensure that you have $INFORMIXDIR set even if the software is
   installed in /usr/informix, and that $INFORMIXDIR/bin is on your PATH.
   The build no longer works unless these environment variables are set.
   Also, if you are using ESQL/C version 6.x or later, you may be using
   ESQL/C shared libraries which are found in $INFORMIXDIR/lib and
   $INFORMIXDIR/lib/esql.  Starting with version 0.95, you will have the
   absolute pathnames of the Informix shared libraries built into your
   DBD::Informix library by default.  This means that you do not need to
   worry about LD_LIBRARY_PATH, LD_RUN_PATH, SHLIB_PATH or LIBPATH at
   runtime, at least for the Informix shared libraries.  The downside of
   this is that if you change the location of your software, you will need
   to rebuild and reinstall DBD::Informix (or you can mess about with
   symlinks to simulate the original INFORMIXDIR).

   If this is unacceptable, you need to set the environment variable
   DBD_INFORMIX_RELOCATABLE_INFORMIXDIR to some value such as "yes".  This
   will use relative names to identify the Informix shared libraries.  You
   will be warned that this is happening.  At both test time and at run
   time, you need to ensure that the Informix shared libraries will be
   found when you run Perl with DBD::Informix.  On SVR4 and Linux
   machines, this means adding these directories to LD_LIBRARY_PATH; on
   HP-UX, the variable is SHLIB_PATH; other systems may have other
   variable names.  You need to set INFORMIXSERVER correctly unless you
   are using version 5.x ESQL/C.  You may need to set other
   Informix-specific environment variables too.  Consult the Informix
   manuals for more information.  And, if you are not yet familiar with
   how to set environment variables, then please get yourself a Unix
   primer (eg "Learning the Unix System, 4th Edition" from O'Reilly,
   http://www.oreilly.com/) and read it!  Yes, I have been asked "How do I
   set the XYZ environment variable?"

   You should take a look at the documentation in InformixTest.pm, and set
   the DBD_INFORMIX_DATABASE, DBD_INFORMIX_USERNAME, DBD_INFORMIX_PASSWORD
   environment variables as appropriate for your system.  Note that
   DBD_INFORMIX_SERVER is no longer used at all.  There is also a parallel
   set of environment variables with the suffix 2 (DBD_INFORMIX_DATABASE2,
   DBD_INFORMIX_USERNAME2, DBD_INFORMIX_PASSWORD2), which can be set to
   specify the second test database completely independently of the first.
   You do not have to set any of these 6 environment variables if the
   defaults are OK.  The default database is 'stores'; no username and
   password are supplied if none is specified.  If you set the username,
   you must also set the password to have any effect.  Although the
   testing does as little damage as possible, it is not a good idea to use
   your prize database for this.  The stores database is a good bet.  Note
   that these variables only have significance when running the
   DBD::Informix tests.  They are not used by DBD::Informix itself, only
   by DBD::InformixTest.  However, the variables should be set before you
   start the build and not changed until after you complete the testing.
   If you do change them, you should check that the esqltest program run
   by 'perl Makefile.PL' still gives your new environment a clean bill of
   health.

   One step in the setup process tests that you have permissions on the
   databases which will be used by the testing.  It does this by compiling
   and running a relatively simple ESQL/C program which simply opens a few
   databases, creates and drops some tables, and exits.  If the test
   fails, you do not get a Makefile so you cannot build DBD::Informix.

   Note that some tests, notably t/t56tabinfo.t and t57tables.t, will fail
   if you have the DELIMIDENT environment variable set.

BUILDING DBD::Informix WITH BUNDLES

   Assuming that Bundle::DBD::Informix is set up correctly with CPAN, and
   that your Informix environment is set up correctly, you can install
   DBD::Informix by simply typing:

       perl -MCPAN -e 'install Bundle::DBD::Informix'

   This will go and fetch the latest version of DBI (and its pre-requisite
   modules), and the latest version of DBD::Informix, and compile, test
   and install them all completely automatically.  Before doing this, you
   need to be confident that things will work correctly (or that you've
   got good backups of your Perl installation).  On the other hand, for
   sheer convenience, it takes a lot of beating.  You could even arrange
   to do this once a week via cron, if you wanted to.

   When you first run this, the CPAN module will ask you a number of
   questions, including the name of a CPAN site that you wish to download
   the material from, but it remembers this information for the next time.

   You should consider installing the latest CPAN bundle first:

       perl -MCPAN -e 'install Bundle::CPAN'

BUILDING DBD::Informix

   When Perl, DBI and ESQL/C are all installed do:

       perl Makefile.PL

   The script will attempt to work out what it needs to build the module.
   Then do:

       make

   This should complete without errors, and ideally without warnings
   either.  If you get warnings, I'm interested to know what they are and
   how they could be fixed generically.  If it fails horribly, see below.

   Do NOT hand edit the generated Makefile unless you are completely sure
   you understand the implications (and are willing to make those changes
   manually every time the Makefile is regenerated)!  Always try to make
   changes by editing Makefile.PL, which is extensively annotated.  You
   should also read the section on ExtUtils::MakeMaker in the 2nd Edition
   of 'Programming Perl'.

   You should never need to make any changes to the generated Makefile,
   nor to Makefile.PL.  If you do *please* let me know so that I can try
   to make it automatic in a later release.

   Then run:

       make test

   Note that testing DBD::Informix does create some tables and databases.
   The database is normally called 'dbd_ix_db', and the table names start
   with 'dbd_ix_'.  Some of the tables are permanent; most are temporary.
   The tests are designed to work whether the tables and database are
   present when the tests start or not; that means they get dropped.  Do
   not run the tests if you have precious tables or databases that begin
   'dbd_ix_'!  As of version 0.61, the cleanup script t/t99clean.t is run
   at the end of the testing.  It removes the tables, views, synonyms, etc
   which might have been created by DBD::Informix.

   On the reference system (Sun Sparc 20 running Solaris 2.6, compiling
   with GCC 2.8.1 or SUNWspro SC4.0.1, using either Perl 5.00404 or 5.00502),
   all the tests pass when DBD::Informix is built with ESQL/C versions
   5.08.UD1, 6.00.UE1, 7.24.UC1 and 9.14.UC1.

   It is a good idea to run:

       make test TEST_VERBOSE=1

   You should inspect the results as not every test compares the actual
   data returned with the data that should be returned (though many of
   them do check the data which is returned).  Note that the blob tests
   pass on SE, because the test scripts detect that the engine is SE and
   do not try to test blob handling.

   Additionally, for a really thorough scrutiny of DBD::Informix, you need
   to test with at least 3 different databases: one created MODE ANSI, one
   created with a transaction log but not MODE ANSI, and one created
   without any transaction logs at all.

       DBD_INFORMIX_DATABASE=mode_ansi make test
       DBD_INFORMIX_DATABASE=logged    make test
       DBD_INFORMIX_DATABASE=unlogged  make test

   If you are concerned about both OnLine and SE, then you need these
   databases for both environments.  Also note that the multiple
   connection tests will use two different databases if you set the
   environment variable DBD_INFORMIX_DATABASE2, but the tests assume that
   you don't need to specify the user and password.  This could be fixed,
   but hasn't happened yet.  You can use one SE and one OnLine database
   for the multiple connection testing.  You can also test with different
   server versions (eg using 7.2x ESQL/C to connect to a 5.0x OnLine) if
   you have the software available.  Note that the tests are not 100%
   clean and can leave the odd table or stored procedure in the database.

   Once you are satisfied that DBD::Informix is working correctly, you
   should install it:

       make install

   If you ever need to remove it, possibly as a preamble to installing a
   new version, you should use the old version's makefile and run:

       make uninstall

   You can then install using the new version's makefile.  It is important
   to use the correct (old or new) makefiles because the installed files
   may be different, and if some file is made obsolete by the new version
   (is not used by the new version), its makefile will not uninstall the
   obsolete file; over time and multiple versions, this could, eventually,
   lead to 'coronary thrombosis' on your disk drive -- or disk full.

   If you run into problems which suggest that the ESQL/C you have won't
   work as dynamically loaded libraries (eg on HP-UX or SCO), then you
   should create a statically linked version of Perl with DBD::Informix
   linked to it.  Use:

       make perl
       make test_static

   Please consult the Notes/Working.Versions file for information about known
   working versions of the software (and specific problem versions).  If
   you are using a combination of versions which is different from any
   previously recorded, please send me ([email protected]) the details for
   your new, successful port.

   If you run into major problems even getting the esqltest program to
   compile, you can try compiling the esqlbasic.ec program using a plain
   ESQL/C command:

       esql -o esqlbasic esqlbasic.ec

   If even this will not compile, you need to concentrate on fixing your
   ESQL/C environment before doing anything else with DBD::Informix.  If
   it compiles but does not run, then you need to ensure that you fix the
   Informix environment so that you can access databases.  Once this test
   both compiles and runs, you will probably be able to compile and test
   DBD::Informix.

   You can suppress the esqltest code in Makefile.PL by setting
   DBD_INFORMIX_NO_ESQLTEST in your environment -- but you may not report
   any problems whatsoever to anybody if you have this set.

KNOWN PROBLEMS:

   * DBD::Informix does not work, and never will work, with ESQL/C Version
     4.0x or 4.1x.  There is a package DBD::Informix4 available from Goran
     Thyni <[email protected]> (version 0.23 is current at
     1999-12-31 and is available from CPAN).

   * Problems have been encountered on HP-UX (both 9.x and 10.x) when
     building DBD::Informix using 5.x and 6.x ESQL/C.  This seems to be
     because the Informix products either do not have shared libraries at
     all or have shared libraries which the HP-UX compilers and loader do
     not accept.  It seems that the only way to build DBD::Informix on
     HP-UX with 5.x or 6.x ESQL/C is to build a statically linked version
     of Perl with the Informix libraries included.  This is a defect in
     ESQL/C rather than Perl, DBI or DBD::Informix.  If you know how to
     build DBD::Informix on HP-UX with version 5.x (or 6.x) ESQL/C without
     doing it statically, please tell everyone.

   * Compiling on HP-UX 10.20 has been problematic.  Please see the
     guidelines in Notes/hpux-10.20 which were supplied by Reed White
     ([email protected]).  Note that the non-ANSI C
     compiler distributed with HP-UX base package is not usable for
     DBD::Informix because it does not accept prototypes.

   * Some problems have been encountered on SCO which seems to be related
     to the equivalent of LD_LIBRARY_PATH on System V Release 4 machines.
     Again, help or reassurance is needed on this.

   * If you are using GCC to compile the software (on Solaris and HP-UX
     10.20 in particular, but probably on other platforms too), ensure
     that you also use GCC to build the shared libraries, rather than
     trying to use 'ld'.  If you use ld instead, you are likely to run
     into problems with an undefined symbol __eprintf.  Please read the
     file Notes/eprintf (contributed by Bernd Gill <[email protected]>).
     You can work around it by setting DBD_INFORMIX_USE_EPRINTF_CODE in
     the environment before running 'perl Makefile.PL'.  You could also
     consider adding DBD_INFORMIX_DISABLE_ASSERT (which also gets rid of
     the __eprintf() problem by disabling any assertions; __eprintf() is
     used by the GNU assert macro).

   * Do not use the GNU assembler or loader with GCC on Solaris; they
     don't work properly with shared libraries.  Remove them and rebuild
     and reinstall GCC immediately.

IF YOU HAVE PROBLEMS BUILDING DBD::INFORMIX

Read the file Notes/bug.reports which describes what to do and where to
send the failure report.  Please ensure that any email message has
DBD::Informix in the subject line -- thanks!

IF YOU HAVE PROBLEMS USING DBD::INFORMIX

If your problem is with your own code and the DBD::Informix tests all pass,
then the initial message should give the version information (see the
Notes/bug.reports file), a description of the problem, a minimal test
script, and the results of running the test script on your machine (along
with an explanation of why the result is wrong -- it may not be obvious to
me -- and what the correct result should be).  Please ensure that any email
message has DBD::Informix in the subject line -- thanks!

The minimal test script should preferably:

(1) Use the stores database, with empty username and password fields.  If
   the test needs a particular type of database (eg with transactions) to
   demonstrate the problem, alternative convenient names are 'logged',
   'unlogged' and 'mode_ansi'.  If you are using SE, please mention that.
(2) Use temporary tables rather than permanent ones.
(3) Load just enough data to show the problem.
(4) Test every statement that uses a DBI function for success.
(5) Clearly indicate when it fails.
(6) Clearly indicate when it passes.
(7) It had better not use DBI->install_driver() without an extremely good
   reason, and I can't immediately think of a reason which would be good
   enough.  It should use the DBI->connect("dbi:Informix:...", ...) form
   for connecting.

If your test is failing with a core dump, the stack trace for it is useful
if it lists function names -- it is not useful if it does not.

SAMPLE CODE

The tests which come with DBD::Informix show a variety of ways of using
DBD::Informix.  Do not use the connection method shown in the code for test
t/t83oconn.t; it is officially obsolete.  DBD::Informix needs to test it, but
you should not.

There are some simple examples of DBI scripts for Informix databases in the
examples sub-directory.  Read the examples/README file for more details.

Remember -- it is supposed to be fun!

This README has grown huge and paranoid because there are lots of little
details which people don't necessarily think of, but which can make the
difference between working code and broken code.

Jonathan Leffler ([email protected])

@(#)$Id: README,v 95.5 1999/12/30 23:21:33 jleffler Exp $

---------------------------------------------------------------------------

Original document: (c) Tim Bunce <[email protected]>
Amendments 1:      (c) Alligator Descartes <[email protected]>
Amendments 2:      (c) Jonathan Leffler <[email protected]>
Amendments 3:      (c) Jonathan Leffler <[email protected]>
Amendments 4:      (c) Jonathan Leffler <[email protected]>

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