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.

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        ***  Note that DBI 1.00 and above is not alpha code!  ***
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PREREQUISITES

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

    1.  Perl 5.004 or later.
    2.  DBI 1.08 or later.
    3.  A C compiler which accepts function prototypes (eg GCC or EGCS).
    4.  Informix ESQL/C 5.00 or later, or ClientSDK.
    5.  A 'stores' database to which you can connect without specifying
        username or password, and in which you can create tables.

    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'.

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 1.08 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 EGCS C Compiler v1.1.2 or later.
    This is the official successor to GCC as of 20th April 1999, and 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 an ANSI C compiler (or, at least, one 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.

                              *** 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 never been tested with a version 8.x (OnLine XPS, now
    known as Informix Dynamic Server Extended Parallel Option or IDS-XPO)
    version of ESQL/C and database.  There will probably be few 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.

    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), and the test will fail if you use olipcshm or
    onipcshm (shared memory) connections to both databases.  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.  You need to ensure that these 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.

BUILDING DBD::Informix WITH BUNDLES

    If your environment is set up correctly, you can simply type:

        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 (j.leffler@acm.org) 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 uses SQL DESCRIPTORS which are not part of ESQL/C
      Version 4.0x or 4.1x.  It also uses string-named cursors and
      statements, which are likewise not supported in 4.0x or 4.1x (or
      earlier) versions.  There is a package DBD::Informix4 available from
      Goran Thyni <goran@bildbasen.kiruna.se> (version 0.22 was current in
      August 1997).  I don't have a working URL for this software.

    * 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
      (REED_WHITE@HP-Corvallis-om1.om.hp.com).  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 <bernd@dsi.co.nz>).
      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.

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 point 3
above, plus the version of the Informix database engine you are using), 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).

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 (j.leffler@acm.org)

@(#)$Id: README,v 62.4 1999/09/19 21:43:55 jleffler Exp $

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Original document: (c) Tim Bunce <Tim.Bunce@ig.co.uk>
Amendments 1:      (c) Alligator Descartes <descarte@arcana.co.uk>
Amendments 2:      (c) Jonathan Leffler <johnl@informix.com>
Amendments 3:      (c) Jonathan Leffler <j.leffler@acm.org>
Amendments 4:      (c) Jonathan Leffler <jleffler@informix.com>
