=item .. create a database to use?
-First, choose a database. For testing/experimenting, we reccommend
+First, choose a database. For testing/experimenting, we recommend
L<DBD::SQLite>, which is a self-contained small database (i.e. all you
need to do is to install L<DBD::SQLite> from CPAN, and it works).
=item .. use DBIx::Class across multiple databases?
-If your database server allows you to run querys across multiple
+If your database server allows you to run queries across multiple
databases at once, then so can DBIx::Class. All you need to do is make
sure you write the database name as part of the
L<DBIx::Class::ResultSource/table> call. Eg:
the tables are to be joined. The condition may contain as many fields
as you like. See L<DBIx::Class::Relationship::Base>.
-=item .. define a relationship across an intermediate table? (many-to-many)
+=item .. define a relationship bridge across an intermediate table? (many-to-many)
-Read the documentation on L<DBIx::Class::Relationship/many_to_many>.
+The term 'relationship' is used loosely with many_to_many as it is not considered a
+relationship in the fullest sense. For more info, read the documentation on L<DBIx::Class::Relationship/many_to_many>.
=item .. stop DBIx::Class from attempting to cascade deletes on my has_many and might_have relationships?
=item .. search with an SQL function on the left hand side?
-To use an SQL function on the left hand side of a comparison:
+To use an SQL function on the left hand side of a comparison you currently need
+to resort to literal SQL:
- ->search({ -nest => \[ 'YEAR(date_of_birth) = ?', [ plain_value => 1979 ] ] });
-
-Note: the C<plain_value> string in the C<< [ plain_value => 1979 ] >> part
-should be either the same as the name of the column (do this if the type of the
-return value of the function is the same as the type of the column) or
-otherwise it's essentially a dummy string currently (use C<plain_value> as a
-habit). It is used by L<DBIx::Class> to handle special column types.
-
-Or, if you have quoting off:
-
- ->search({ 'YEAR(date_of_birth)' => 1979 });
+ ->search( \[ 'YEAR(date_of_birth) = ?', 1979 ] );
=item .. find more help on constructing searches?
L<DBIx::Class::ResultSet/order_by> attributes to order your data and
pick off a single row.
-See also L<DBIx::Class::Manual::Cookbook/Retrieve_one_and_only_one_row_from_a_resultset>.
+See also L<DBIx::Class::Manual::Cookbook/Retrieve one and only one row from a resultset>.
A less readable way is to ask a regular search to return 1 row, using
L<DBIx::Class::ResultSet/slice>:
Use L<DBIx::Class::Row/discard_changes>.
- $row->discard_changes
+ $result->discard_changes
-Discarding changes and refreshing from storage are two sides fo the same coin. When you
+Discarding changes and refreshing from storage are two sides of 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<DBIx::Class::Row/discard_changes> does just that by re-fetching the row from storage
=item .. insert a row with an auto incrementing primary key?
This happens automatically. After
-L<creating|DBIx::Class::ResultSet/create> a row object, the primary
+L<creating|DBIx::Class::ResultSet/create> a result object, the primary
key value created by your database can be fetched by calling C<id> (or
the access of your primary key column) on the object.
=item .. update a column using data from another column?
-To stop the column name from being quoted, you'll need to supply a
-scalar reference:
+To stop the column name from being quoted, you'll need to tell DBIC
+that the right hand side is an SQL identifier (it will be quoted
+properly if you have quoting enabled):
- ->update({ somecolumn => \'othercolumn' })
+ ->update({ somecolumn => { -ident => 'othercolumn' } })
This method will not retrieve the new value and put it in your Row
object. To fetch the new value, use the C<discard_changes> method on
the Row.
# will return the scalar reference:
- $row->somecolumn()
+ $result->somecolumn()
# issue a select using the PK to re-fetch the row data:
- $row->discard_changes();
+ $result->discard_changes();
# Now returns the correct new value:
- $row->somecolumn()
+ $result->somecolumn()
To update and refresh at once, chain your calls:
- $row->update({ 'somecolumn' => \'othercolumn' })->discard_changes;
+ $result->update({ 'somecolumn' => { -ident => 'othercolumn' } })->discard_changes;
=item .. store JSON/YAML in a column and have it deflate/inflate automatically?
=head2 Custom methods in Result classes
-You can add custom methods that do arbitrary things, even to unrelated tables.
-For example, to provide a C<< $book->foo() >> method which searches the
+You can add custom methods that do arbitrary things, even to unrelated tables.
+For example, to provide a C<< $book->foo() >> method which searches the
cd table, you'd could add this to Book.pm:
sub foo {
write your own methods, you can.
For example, to provide a C<< $book->foo() >> method to manually implement
-what create_related() from L<DBIx::Class::Relationship::Base> does, you could
+what create_related() from L<DBIx::Class::Relationship::Base> does, you could
add this to Book.pm:
sub foo {
=item How do I store my own (non-db) data in my DBIx::Class objects?
-You can add your own data accessors to your classes.
+You can add your own data accessors to your Result classes.
One method is to use the built in mk_group_accessors (via L<Class::Accessor::Grouped>)
- package MyTable;
+ package App::Schema::Result::MyTable;
- use parent 'DBIx::Class';
+ use parent 'DBIx::Class::Core';
__PACKAGE__->table('foo'); #etc
__PACKAGE__->mk_group_accessors('simple' => qw/non_column_data/); # must use simple group
An another method is to use L<Moose> with your L<DBIx::Class> package.
- package MyTable;
+ package App::Schema::Result::MyTable;
use Moose; # import Moose
use Moose::Util::TypeConstraint; # import Moose accessor type constraints
- extends 'DBIx::Class'; # Moose changes the way we define our parent (base) package
+ extends 'DBIx::Class::Core'; # Moose changes the way we define our parent (base) package
has 'non_column_data' => ( is => 'rw', isa => 'Str' ); # define a simple attribute
__PACKAGE__->table('foo'); # etc
-With either of these methods the resulting use of the accesssor would be
+With either of these methods the resulting use of the accessor would be
- my $row;
+ my $result;
- # assume that somewhere in here $row will get assigned to a MyTable row
+ # assume that somewhere in here $result will get assigned to a MyTable row
- $row->non_column_data('some string'); # would set the non_column_data accessor
+ $result->non_column_data('some string'); # would set the non_column_data accessor
# some other stuff happens here
- $row->update(); # would not inline the non_column_data accessor into the update
+ $result->update(); # would not inline the non_column_data accessor into the update
=item How do I use DBIx::Class objects in my TT templates?
if you create a resultset using C<search> in scalar context, no query
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.
+you ask the resultset for an actual result object.
=item How do I deal with tables that lack a primary key?
=item How do I reduce the overhead of database queries?
You can reduce the overhead of object creation within L<DBIx::Class>
-using the tips in L<DBIx::Class::Manual::Cookbook/"Skip row object creation for faster results">
+using the tips in L<DBIx::Class::Manual::Cookbook/"Skip result object creation for faster results">
and L<DBIx::Class::Manual::Cookbook/"Get raw data for blindingly fast results">
=item How do I override a run time method (e.g. a relationship accessor)?
package Your::Schema::Group;
use Class::Method::Modifiers;
-
+
# ... declare columns ...
-
+
__PACKAGE__->has_many('group_servers', 'Your::Schema::GroupServer', 'group_id');
__PACKAGE__->many_to_many('servers', 'group_servers', 'server');
-
+
# if the server group is a "super group", then return all servers
# otherwise return only servers that belongs to the given group
around 'servers' => sub {
package Your::Schema::Group;
use Method::Signatures::Simple;
-
+
# ... declare columns ...
-
+
__PACKAGE__->has_many('group_servers', 'Your::Schema::GroupServer', 'group_id');
__PACKAGE__->many_to_many('servers', 'group_servers', 'server');
-
+
# The method keyword automatically injects the annoying my $self = shift; for you.
method servers {
return $self->result_source->schema->resultset('Server')->search({ ... });
package Your::Schema::Group;
use Sub::Name;
-
+
# ... declare columns ...
-
+
__PACKAGE__->has_many('group_servers', 'Your::Schema::GroupServer', 'group_id');
__PACKAGE__->many_to_many('servers', 'group_servers', 'server');
-
+
*servers = subname servers => sub {
my $self = shift;
return $self->result_source->schema->resultset('Server')->search({ ... });
};
-
+
=back
=head2 Notes for CDBI users
projects / dbsrgits/DBIx-Class.git / blobdiff