X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FManual%2FFAQ.pod;h=aa7cf30cd83965ee68f48f093766e2b14f5fbc1e;hb=b85be4c1866c89282d6ff5ab4b8f70ddcff440fa;hp=0f3fa4ab24b232f0eaeb0c0955ea8de4904ae3cb;hpb=c6d52fe4a17d92abfcd7f7fba782c81dcdaf71cd;p=dbsrgits%2FDBIx-Class-Historic.git diff --git a/lib/DBIx/Class/Manual/FAQ.pod b/lib/DBIx/Class/Manual/FAQ.pod index 0f3fa4a..aa7cf30 100644 --- a/lib/DBIx/Class/Manual/FAQ.pod +++ b/lib/DBIx/Class/Manual/FAQ.pod @@ -232,6 +232,25 @@ and not: my $interval = "now() - interval '12 hours'"; ->search({last_attempt => { '<' => \$interval } }) +=item .. search with an SQL function on the left hand side? + +To use an SQL function on the left hand side of a comparison: + + ->search({}, { where => \'YEAR(date_of_birth)=1979' }); + +=begin hidden + +(When the bind arg ordering bug is fixed, the previous example can be +replaced with the following.) + + ->search({}, { where => \'YEAR(date_of_birth)=?', bind => [ 1979 ] }); + +=end hidden + +Or, if you have quoting off: + + ->search({ 'YEAR(date_of_birth' => 1979 }); + =item .. find more help on constructing searches? Behind the scenes, DBIx::Class uses L to help construct @@ -285,6 +304,18 @@ Why slice instead of L or L. + + $row->discard_changes + +Discarding changes and refreshing from storage are two sides fo the same coin. When you +want to discard your local changes, just re-fetch the row from storage. When you want +to get a new, fresh copy of the row, just re-fetch the row from storage. +L does just that by re-fetching the row from storage +using the row's primary key. + =back =head2 Inserting and updating data @@ -388,6 +419,17 @@ is executed. You can create further resultset refinements by calling search again or relationship accessors. The SQL query is only run when you ask the resultset for an actual row object. +=item How do I deal with tables that lack a primary key? + +If your table lacks a primary key, DBIx::Class can't work out which row +it should operate on, for example to delete or update. However, a +UNIQUE constraint on one or more columns allows DBIx::Class to uniquely +identify the row, so you can tell L these +columns act as a primary key, even if they don't from the database's +point of view: + + $resultset->set_primary_key(@column); + =back =head2 Notes for CDBI users