Current DBI Implementation Notes:
$ary_ref = $sth->fetch; currently always returns the same array ref.
This may be a feature that stays, then again it may not.
$sth->bind_param currently takes a variable value not a reference.
That may change later.
*** MANY THINGS MAY CHANGE *** See README file ***
Changes in DBI 0.70, 16 June 1996
Added extra invalid handle check (dbih_getcom)
Fixed broken $dbh->quote method.
Added check for old GCC in Makefile.PL
Changes in DBI 0.69
Fixed small memory leak.
Clarified the behaviour of DBI->connect.
$dbh->do now returns '0E0' instead of 'OK'.
Fixed "Can't read $DBI::errstr, lost last handle" problem.
Changes in DBI 0.68, 2 Mar 1996
Changes to suit perl5.002 and site_lib directories.
Detects old versions ahead of new in @INC.
Changes in DBI 0.67, 15 Feb 1996
Trivial change to test suite to fix a problem shown up by the
Perl5.002gamma release Test::Harness.
Changes in DBI 0.66, 29 Jan 1996
Minor changes to bring the DBI into line with 5.002 mechanisms,
specifically the xs/pm VERSION checking mechanism.
No functionality changes. One no-last-handle bug fix (rare problem).
Requires 5.002 (beta2 or later).
Changes in DBI 0.65, 23 Oct 1995
Added $DBI::state to hold SQL CLI / ODBC SQLSTATE value.
SQLSTATE "00000" (success) is returned as "" (false), all else is true.
If a driver does not explicitly initialise it (via $h->{State} or
DBIc_STATE(imp_xxh) then $DBI::state will automatically return "" if
$DBI::err is false otherwise "S1000" (general error).
As always, this is a new feature and liable to change.
The is *no longer* a default error handler!
You can add your own using push(@{$h->{Handlers}}, sub { ... })
but be aware that this interface may change (or go away).
The DBI now automatically clears $DBI::err, errstr and state before
calling most DBI methods. Previously error conditions would persist.
Added DBIh_CLEAR_ERROR(imp_xxh) macro.
DBI now EXPORT_OK's some utility functions, neat($value),
neat_list(@values) and dump_results($sth).
Slightly enhanced t/min.t minimal test script in an effort to help
narrow down the few stray core dumps that some porters still report.
Renamed readblob to blob_read (old name still works but warns).
Added default blob_copy_to_file method.
Added $sth = $dbh->tables method. This returns an $sth for a query
which has these columns: TABLE_CATALOGUE, TABLE_OWNER, TABLE_NAME,
TABLE_TYPE, REMARKS in that order. The TABLE_CATALOGUE column
should be ignored for now.
Changes in DBI 0.64, 23 Oct 1995
Fixed 'disconnect invalidates 1 associated cursor(s)' problem.
Drivers using DBIc_ACTIVE_on/off() macros should not need any changes
other than to test for DBIc_ACTIVE_KIDS() instead of DBIc_KIDS().
Fixed possible core dump in dbih_clearcom during global destruction.
Changes in DBI 0.63, 1 Sep 1995
Minor update. Fixed uninitialised memory bug in method
attribute handling and streamlined processing and debugging.
Revised usage definitions for bind_* methods and readblob.
Changes in DBI 0.62, 26 Aug 1995
Added method redirection method $h->func(..., $method_name).
This is now the official way to call private driver methods
that are not part of the DBI standard. E.g.:
@ary = $sth->func('ora_types');
It can also be used to call existing methods. Has very low cost.
$sth->bind_col columns now start from 1 (not 0) to match SQL.
$sth->bind_columns now takes a leading attribute parameter (or undef),
e.g., $sth->bind_columns($attribs, \$col1 [, \$col2 , ...]);
Added handy DBD_ATTRIBS_CHECK macro to vet attribs in XS.
Added handy DBD_ATTRIB_GET_SVP, DBD_ATTRIB_GET_BOOL and
DBD_ATTRIB_GET_IV macros for handling attributes.
Fixed STORE for NUM_OF_FIELDS and NUM_OF_PARAMS.
Added FETCH for NUM_OF_FIELDS and NUM_OF_PARAMS.
Dispatch no longer bothers to call _untie().
Faster startup via install_method/_add_dispatch changes.
Changes in DBI 0.61, 22 Aug 1995
Added $sth->bind_col($column, \$var [, \%attribs ]);
This method enables perl variable to be directly and automatically
updated when a row is fetched. It requires no driver support
(if the driver has been written to use DBIS->get_fbav).
Currently \%attribs is unused.
Added $sth->bind_columns(\$var [, \$var , ...]);
This method is a short-cut for bind_col which binds all the
columns of a query in one go (with no attributes). It also
requires no driver support.
Added $sth->bind_param($parameter, $var [, \%attribs ]);
This method enables attributes to be specified when values are
bound to placeholders. It also enables binding to occur away
from the execute method to improve execute efficiency.
The DBI does not provide a default implementation of this.
See the DBD::Oracle module for a detailed example.
The DBI now provides default implementations of both fetch and
fetchrow. Each is written in terms of the other. A driver is
expected to implement at least one of them.
More macro and assorted structure changes in DBDXS.h. Sorry!
The old dbihcom definitions have gone. All fields have macros.
The imp_xxh_t type is now used within the DBI as well as drivers.
Drivers must set DBIc_NUM_FIELDS(imp_sth) and DBIc_NUM_PARAMS(imp_sth).
test.pl includes a trivial test of bind_param and bind_columns.
Changes in DBI 0.60, 17 Aug 1995
This release has significant code changes but much less
dramatic than the previous release. The new implementors data
handling mechanism has matured significantly (don't be put off
by all the struct typedefs in DBIXS.h, there's just to make it
easier for drivers while keeping things type-safe).
The DBI now includes two new methods:
do $dbh->do($statement)
This method prepares, executes and finishes a statement. It is
designed to be used for executing one-off non-select statements
where there is no benefit in reusing a prepared statement handle.
fetch $array_ref = $sth->fetch;
This method is the new 'lowest-level' row fetching method. The
previous @row = $sth->fetchrow method now defaults to calling
the fetch method and expanding the returned array reference.
The DBI now provides fallback attribute FETCH and STORE functions
which drivers should call if they don't recognise an attribute.
THIS RELEASE IS A GOOD STARTING POINT FOR DRIVER DEVELOPERS!
Study DBIXS.h from the DBI and Oracle.xs etc from DBD::Oracle.
There will be further changes in the interface but nothing
as dramatic as these last two releases! (I hope :-)
Changes in DBI 0.59 15 Aug 1995
NOTE: THIS IS AN UNSTABLE RELEASE!
Major reworking of internal data management!
Performance improvements and memory leaks fixed.
Added a new NullP (empty) driver and a -m flag
to test.pl to help check for memory leaks.
Major changes to DBI/DBD interface include:
1. All imp_xxh_t structs must now have a dbih_ccc_t struct
as the first element in the structure.
2. The previous initialisation scheme of
# create and init private data structure
$imp_data = _private_func(...);
# create handle and reference private data structure
$xxh = DBD::_new_xxh({...}, $imp_data);
is now
# publish size of overall structure required
$imp_data_size = ...; # sizeof(imp_xxh_t)
# create 'blank' handle of required size
$xxh = DBD::_new_xxh({...});
# init private data into space in handle
_private_func($xxh, ...);
_private_func moves 'down' to the next level of handle class.
E.g. a previous
$imp_data = ...::dr::_login(...)
becomes
...::db::_login($dbh,...)
3. The local variable initialisation scheme of
foo(sth)
{
D_dbihcom(sth);
D_imp_sth;
is now
foo(sth)
{
D_imp_sth(sth);
also: D_imp_dbh_from_sth;
and: D_imp_drh_from_dbh;
if needed.
Study DBD::Oracle version 0.21 for more details.
(Comparing parts of v0.21 with v0.20 may be useful.)
Known Problems:
1. A Perl5.001m binary built with -DDEBUGGING seems to
cause (@row = $sth->fetchrow) to be called in a scalar
context. Works fine using a non -DDEBUGGING perl.
This might be a local problem. Please report to findings.
Changes in DBI 0.58 21 June 1995
Added DBI->internal->{DebugLog} = $filename;
Reworked internal logging.
Added $VERSION.
Made disconnect_all a compulsary method for drivers.