Revision history for Perl extension Tangram.

0.01  Sun Mar 21 10:46:45 1999
	- original version; created by h2xs 1.18

0.03  Stardate: unknown
	- first public alpha release

0.08  Stardate: unknown
	- second public alpha release

0.09  Stardate: unknown

   - split Tangram.pm into several modules
   - replaced @ISA with 'use base'
   - replaced default typetags with automounting
   - prefetch now takes either class or remote
   - implemented prefetch for IntrArray and IntrSet
      *::prefetch still need real-life testing,
      especially when class(coll) <> class(item)

1.00  Nov 07 1999 - first mature release version
	- deploy() now also works directly on DBI handles
	- deploy() allows specification of SQL types via the schema hash
	- intrusive collections allow element-to-container navigation
	- improve speed of read_object
	- fixed various bugs
	- rewrote part of, and expanded documentation

1.01  Nov 12 1999 - interim version
	- added (raw) mapping between Perl strings and date/time SQL types

1.02  Nov 14 1999 - interim version
	- added support for aggregated refs, arrays and sets

1.03  Dec 28 1999 - interim version
	- added support for customizing object & class id types, etc
	- as a consequence Tangram should now work with PostgreSql
	- fixed bug: erase() failed in presence of stateless leaf classes
	- temporarily removed RawDate and RawTime tests because M$ SQL
	  cannot handle them; those modules are still present though

1.04  Jan 03 2000 - interim version
	- fixed two bugs related to explicit tables

1.05  Jan 03 2000 - interim version
	- fixed: Storage::prefetch now works with inherited members
	- fixed: _insert() ignored collections in stateless classes

1.06  Feb 29 2000 - higly experimental interim version
	- added typechecks on collection members
	- started cleaning up autovivification of colls upon save
	- documented like()
	- documented extended select options retrieve, order & filter
	- changed _limit into the Limit in test suite
	- added temporary hack in Makefile.PL to support Access
	- added mapping for flat arrays
	- factorized code common to Array & FlatArray

1.07  Feb 29 2000 - interim version
	- adapted test suite for Sybase and other NULL-picky databases
	- added experimental support for vendor extensions (Dialect)
	- added skeleton Dialect::Sybase with support for datepart
	- did extensive rework on Expr instantiation
	- began documenting Type
	- added Storage::reload()

1.08  Mar 26 2000 - interim version
	- batch allocation of object ids
	- support for Lobs contributed by marian.kelc@ruhr-uni-bochum.de
	- Storage::reset()

1.09  ? - interim version
	- String calls DBI for correct quoting, as Marian Kelc suggested
	- fixed Array problem when removing elements from middle of collection
	- (?)

1.10  Apr 19 2000 - interim version
	- changed reset() into unload() and added support for partial unloading
	- tx_do() can now propagate arguments to closure/anon-sub;
	  insert(), update() and erase() pass anon-subs to tx_do to prevent
	  leaks (thanks Radu Greab)

1.11  May 29 2000 - public version
	- ordering result set by descending order is now supported
	- die() on attempt to load from an invalid id
	- removed silly table id allocation limit (t1000) in Coll.pm

1.13  Jul 11 2000 - interim version
	- new FlatHash and DMDateTime mappings contributed by Gabor Herr
          <herr@iti.informatik.tu-darmstadt.de>
	- some more doc in Type.pod
	- date & time doc moved to DateTime.pod
	- deploy() puts \n between instructions in trace

1.15  Jul 21 2000 - interim version
	- new PerlDump mapping contributed by Gabor Herr
          <herr@iti.informatik.tu-darmstadt.de>

1.16  Jul 25 2000 - interim version
	- fixed deploy() bug: didn't take col names into account for Array, Set and Hash
	- fixed query_expr bug in Scalar and Ref: used field name instead of col name

1.17  Jul 28 2000 - interim version
	- Gabor's patches on deep updates

1.18  Jul 28 2000 - stable version
	- weakrefs!
	- tuples
	- mysql tx acquired lock regardless of tx nesting

1.19  Jul 28 2000 - stable version
	- improved id allocation for mysql
	- bitwise operators for mysql
	- manual class id allocation
	- install now works in the absence of DBI and Set::Object
	- Makefile.PL prerequisites work now
	- Guided Tour is now generated & can be run
	- added support for LIMIT in selects
	- deploy() didn't take explicit oid/cid type into account; fixed
	- deploy() wrongly defaulted to NULLable types; fixed
	- class id can now be specified
	- oid and cid now default to INTEGER
	- fixed error in Expr.pod but I don't remember what it was	
	- minor improvement to Schema.pod
	- added Springfield.pm for users to play with
	- added support for SELECT SUM

2.00  Feb ?? 2001 - first S.O.L. release
	- added copyright notices
	- added a copy of the GPL
	- implemented inlined exports
	- INSERT and UPDATE now make use of prepared statements when available
	- re-executable Cursors
	- changed database layout, Class Table is gone and 'control' table in there
	- object ids are no longer allocated on a class basis
	- introduced Tangram::Relational
	- dialect are now done via derivation
	- stored object id no longer contains type id
	- introduced Relational::Engine
	- flexible mapping

2.05pre1 May 2003 - SamV - first "not the momma" release

	- Patches from lots of people, don't know who 'coz the honourable
	  grand master JLL applied a lot of them, I'll try to summarize
	  here:
	
		- back-porting pieces for 5.00503 (that was me)
		- a more elegant solution for the
		  Tangram::AbstractArray/AbstractHash corner case than
		  the one I submitted :-)
		- code that (possibly) completes Tangram::Hash support (I
		  haven't written a test case to confirm this yet)
		- A fix to Tangram::AbstractSet that again caters to some
		  very strange corner cases (this was me too)
		- Working implementation of the Tangram::DMDateTime type
		  mapping, a good thing that running a persistent
		  application server offsets the huge time it takes to
		  load in Date::Manip :-)
		- A bug fix to Tangram::FlatArray mapping type that
		  affects deleting members (don't know whose)
		- Tangram::IntrSet::get_intrusions (? can anyone claim
		  or explain this one?)
		- Minor Tangram::PerlDump fix (a simple one)
		- Deep, deep magic in Tangram::Relational::Engine;
		  new function get_heterogeneity (anyone?)
		- Use of uninitialised variable in Tangram::Engine...
		- Other large changes to Tangram::Schema (? - get_bases,
		  get_specs, is_root, etc)
		- A problem with merging schemas when you used a
		  `back-ref' to a class that is later on in the schema
		  (me)
		- Scattered showers of changes in Tangram::Storage
		  (get_insert_statements etc, lots of `off by one'
		  (reference nesting level that is) changes)
	
	- All I can say is that there have been some very smart people
	  looking at this code and submitting patches.

2.05pre2 Jun 2003 - SamV
	- Minor Tangram::Expr defined vs logically-false fix
	  (Aaron Mackey)
	- explicitly select all ORDER BY columns (Aaron Mackey)
	- normalise default "slot" and "coll" column names in
	  Tangram::Intr* types (SamV)

2.05 Jul 2003 - SamV
	- Tangram::Scalar and Tangram::Ref column names are now passed
	  through $schema->{normalize}->()

2.06 Jul 17 2003 - SamV
	- Added $storage->oid_isa($oid, "ClassName") method for
	  marshalling OIDs
	- Fixed minor bugs causing test suite to issue large warnings
	  on 5.8.1-RC2

2.07 Nov 8 2003 - SamV
	- Fixed bug with Tangram::Intr* and erasing objects that
	  referred to a class which didn't use their class name as
	  their table name [closes: 2650]
	- Added the ability to use limit => [ N, Y ] in
	  Tangram::Storage->select statements
	- Added Tangram::Coll::includes_or; see the man page for
	  Tangram::Expr
	- Enhancement of error message from
	  Tangram::Relational::Engine [related to 2631]
	- Support for using table types via $schema->{sql}{table_type}
	- Support for sub-selects with MySQL, for the one test that
	  uses them.  Also $storage->{no_subselects} is auto-detected.
	- Completed $storage->prefetch() function for all working
	  types, new test t/prefetch.t
	- If you have NULL values in array or hash slots in your
	  database, then it won't cause a hard error, except possibly
	  with prefetch() [related to 2631]
	- Various small fixes to bizarre internal error messages
	  [related to 2631]
	- Minor documentation fixes
	- Exceptions on various DB failures are now thrown when
	  DBI::execute() is called internally, rather than being
	  largely ignored.
	- Cosmetic Test Suite changes
	- ID column name wasn't being used for the index in
          Tangram::Relational::Engine (Kurt Stephens)
        Lost patches from 2002/06/25 (Kurt Stephens):
        - Added missing Tangram::Expr and Tangram::Filter operators:
            '+', '-', '*', '/',
            '&', '|', '!',
            '==', '!=', '<', '>', '<=', '>=',
            'eq', 'ne', 'lt', 'gt', 'le', 'ge',
            'cos', 'sin', 'acos',
        - Added argument swapping for non-commutative operators, like
	  "<".
        - Fixed export problem with 5.6.1 (reported by Kate Pugh)
	- deep_update with Tangram::Ref bug fix (reported by Aaron Mackey)
	- Makefile.PL should now hopefully be more informative about
	  which modules are needed for what.
	- Removed Selfloader from Tangram::Ref (Kate Pugh)

2.07.1, 29-Dec-2003 - SamV

	- Tangram::IntrHash implemented at last :-).  Tangram::IxHash
          and Tangram::IntrIxHash are next :->
	- verbose error message in Tangram::Coll when demand paging is
	  happening on stale tied collections (eg, erroneously created
	  via dclone())
	- some reformatting, as I grasp more of the code.
	- fix for Postgres sub-select detection (Pedro Alves)
	- make_1st_id_in_tx now only called for 1st insert
	  (Chengzhi Liang)

2.07.2, 6-Jan-2004 - SamV

	- Tangram::IntrHash prefetch test added
	- Documentation enhancements
	- Tangram::Dump class to `fix' persistent references in data
	  structures prior to insertion, so that :
	- Tangram::PerlDump now can contain persistent objects safely
	- and hey, why not write a Tangram::Storable 
	- and a Tangram::YAML (not working, waiting for a CPAN bug to
	  be fixed)

2.07_03, 17-May-2004 - SamV
	- Added Tangram::IDBIF to combine multiple object fields into
	  one perl_dump style field (including a "catch-all" facility)
	  Test suite for this isn't complete yet.

	Most changes from Kurt <ks.perl@kurtstephens.com>, with many
	thanks:

        - Do not $self->{db}->disconnect in Storage::disconnect() and
          DESTROY(), if $self->{db} eq $opts->{dbh} in
          Tangram::Storage->connect($schema, $cs, $user, $pw, { 'dbh'
           => ... } ); See $self->{db_owned}.
        - Handle objects that lazily initialize Tangram::AbstractSet 
          Set::Object fields.  See UMMF.
        - Added IntrRef.pm ("Intrusive Ref") for 1-to-1 bi-directional 
          Association navigation using only one column in one table.
          Derived from IntrSet.  I need help with this one. :)
	- Added @sums = $storage->sum([ $expr1, $expr2 ], ...) support.
	- Added support for reused tables for mapping both sides of
          many-to-many UML Associations to the same table with Tangram::Set
          and Tangram::Array. See UMMF's example/ex1.
	- Added support for timestamping all tables through
          $schema->{sql}{timestamp_all_tables}.
        - Prevent additional records in Tangram control table on redeploy.
        - Added support for GROUP BY in Tangram::Cursor.
        - Added COUNT($remote) and SUM($filter_expr) support.

	Editorial release changes:
		
	- [SamV] Started using _NN version style, so CPAN marks it as
	  a development release
	- added brief test suite for aggregate functions

2.07_04, 20-May-2004

	- Various POD modifications, including the main Tangram page,
	  the addition of Tangram::Complicity and the removal of
	  bogus Tangram::Dialect
	- Enhanced TRACE messages
	- Added support for Oracle via Tangram::Oracle
	- Added support for cursors that select no objects (just
	  retrieve extra columns, eg for aggregate selects)
	- `Fixed' t/datetime.t so that it doesn't do PostgreSQL/MySQL
	  specific tests unless it is running on those databases
	- Storage and Engine now holds a handle to the
	  Tangram::Relational object that created them, allowing for
	  various DBMS dependant hooks (used to rewrite column types,
	  format dates, etc)
	- Extra sanity checking in the core
	- The id_col feature in Tangram::Schema now actually works
          :-).  Previously, there were many places where .id was
          hard-coded.
	- Added ->in() method, an expr that allows direct use of the
          SQL IN () construct, rather than just via includes_or(), or
          with Collections.
	- DMDateTime module now expects database to understand the
          ISO-8601 date format, but the MySQL driver has been enhanced
          to convert ISO-8601 to MySQL format.
	- New method Tangram::Storage::unload_all

2.07_05, 31-May-2004

	- fix so that Tangram::Cursor->new() can retrieve no objects,
	  with no filter (just retrieve => [])
	- when retrieving no object, Tangram::Storage->select() now
	  returns the residue as an array ref (or, if only one column
	  is asked for, simply returns all of the column values as a
	  list).
	- the ->in() Tangram::Expr method now works on columns as well
	  as table aliases.  For now, only integer columns work as no
	  SQL escaping is performed.
	- (Pixie API compliance) You can now insert objects of classes
	  not in the Schema, though only with an "idbif" column in the
	  class will the type be stored.  Full tests pending.
	- new function $storage->import_object("ClassName", $id),
	  which will load an object of the given ID (without the CID)
	- Tangram::YAML strips YAML header and end of line from dumped
	  YAML stream.
	- Added several previously internal Tangram::Storage methods
	  to the official API.
