From 5d6f38c3bcdf0d75e477a32109e09b67343bcfb5 Mon Sep 17 00:00:00 2001 From: zby Date: Tue, 7 Oct 2008 14:42:53 +0000 Subject: [PATCH] Doc changes. --- lib/DBIx/Class/ResultSet/RecursiveUpdate.pm | 90 ++++++++++++++------ t/var/dvdzbr.db | Bin 26624 -> 26624 bytes 2 files changed, 63 insertions(+), 27 deletions(-) diff --git a/lib/DBIx/Class/ResultSet/RecursiveUpdate.pm b/lib/DBIx/Class/ResultSet/RecursiveUpdate.pm index 64fe03e..7115aaa 100644 --- a/lib/DBIx/Class/ResultSet/RecursiveUpdate.pm +++ b/lib/DBIx/Class/ResultSet/RecursiveUpdate.pm @@ -43,7 +43,7 @@ sub recursive_update { } #warn Dumper($object->{_column_data}); use Data::Dumper; } - _delete_empty_auto_increment($object); + $self->_delete_empty_auto_increment($object); $object->update_or_insert; # updating relations that can be done only after the row is inserted into the database @@ -99,7 +99,7 @@ sub get_m2m_source { sub _delete_empty_auto_increment { - my ( $object ) = @_; + my ( $self, $object ) = @_; for my $col ( keys %{$object->{_column_data}}){ if( $object->result_source->column_info( $col )->{is_auto_increment} and @@ -160,7 +160,7 @@ DBIx::Class::ResultSet::RecursiveUpdate - like update_or_create - but recursive =head1 VERSION -This document describes DBIx::Class::ResultSet::RecursiveUpdate version 0.0.1 +This document describes DBIx::Class::ResultSet::RecursiveUpdate version 0.001 =head1 SYNOPSIS @@ -185,30 +185,66 @@ Then: =head1 DESCRIPTION - You can feed the ->create method with a recursive datastructure and have the related records - created. Unfortunately you cannot do a similar thing with update_or_create - this module - tries to fill that void. - - It is a base class for ResultSets providing just one method: recursive_update - which works just like update_or_create but can recursively update or create - data objects composed of multiple rows. All rows need to be identified by primary keys - - so you need to provide them in the update structure (unless they can be deduced from - the parent row - for example when you have a belongs_to relationship). - When creating new rows in a table with auto_increment primary keys you need to - put 'undef' for the key value - this is then removed - and a correct INSERT statement is generated. - - For a many_to_many (pseudo) relation you can supply a list of primary keys - from the other table - and it will link the record at hand to those and - only those records identified by them. This is convenient for handling web - forms with check boxes (or a SELECT box with multiple choice) that let you - update such (pseudo) relations. - - For a description how to set up base classes for ResultSets see load_namespaces - in DBIx::Class::Schema. - - The support for many to many pseudo relationships should be treated as prototype - - the DBIC author disagrees with the way I did it. +You can feed the ->create method with a recursive datastructure and have the related records +created. Unfortunately you cannot do a similar thing with update_or_create - this module +tries to fill that void. + +It is a base class for ResultSets providing just one method: recursive_update +which works just like update_or_create but can recursively update or create +data objects composed of multiple rows. All rows need to be identified by primary keys +- so you need to provide them in the update structure (unless they can be deduced from +the parent row - for example when you have a belongs_to relationship). +When creating new rows in a table with auto_increment primary keys you need to +put 'undef' for the key value - this is then removed +and a correct INSERT statement is generated. + +For a many_to_many (pseudo) relation you can supply a list of primary keys +from the other table - and it will link the record at hand to those and +only those records identified by them. This is convenient for handling web +forms with check boxes (or a SELECT box with multiple choice) that let you +update such (pseudo) relations. + +For a description how to set up base classes for ResultSets see load_namespaces +in DBIx::Class::Schema. + +=head1 DESIGN CHOICES + +=head2 Treatment of many to many pseudo relations + +Matt Trout expressed following criticism of the support for many to many in +RecursiveUpdate and since this is an extension of his DBIx::Class I feel obliged to +reply to it. It is about two points leading in his opinion to 'fragile and +implicitely broken code'. + +1. That I rely on the fact that + + if($object->can($name) and + !$object->result_source->has_relationship($name) and + $object->can( 'set_' . $name ) + ) + +then $name must be a many to many pseudo relation. And that in a +similarly ugly was I find out what is the ResultSource of objects from +that many to many pseudo relation. + +2. That I treat uniformly relations and many to many (which are +different from relations because they require traversal of the bridge +table). + +To answer 1) I've refactored that 'dirty' code into is_m2m and get_m2m_source so +that it can be easily overridden. I agree that this code is not too nice - but +currenlty it is the only way to do what I need - and I'll replace it as soon as +there is a more clean way. I don't think it is extremely brittle - sure it will +break if many to many (pseudo) relations don't get 'set_*' methods anymore - but +I would say it is rather justified for this kind of change in underlying library +to break it. + + +Ad 2) - first this is not strictly true - RecursiveUpdate does have +different code to cope with m2m and other cases (see the point above for +example) - but it let's the user to treat m2m and 'normal' relations in a +uniform way. I consider this a form of abstraction - it is the work that +RecursiveUpdate does for the programmer. =head1 INTERFACE diff --git a/t/var/dvdzbr.db b/t/var/dvdzbr.db index 508afcd73e0131a7a0c143bff992e1a17846003b..c279b90af5bd6b1cb92622e17086708918e5ff1a 100644 GIT binary patch delta 209 zcmZp;z}Rqsae|akyetC*NCGK#1_qsF8+FbyvkL)vTn9xrvHVkD`Q$T0c8%6&%0$@f(Y z8JQ*rs`)cAPhO~2&B!uYR$Z5ob@B#3vB_C}u8eFzR^%oP9~MTw$rJUZCePC0n=F|u zGkKzp9wYnY13Ddy9FskDa~L@%@9@oLY1BT*HJQtIHA^GgLGH;{^g0-MCdcX -- 2.43.0