=item * NOTE
If you're using the old deprecated C<< $rsrc_instance->name(\'( SELECT ...') >>
-method for custom SQL execution, you are highly encouraged to update your code
+method for custom SQL execution, you are highly encouraged to update your code
to use a virtual view as above. If you do not want to change your code, and just
want to suppress the deprecation warning when you call
L<DBIx::Class::Schema/deploy>, add this line to your source definition, so that
# FROM artist
Note that the C<as> attribute B<has absolutely nothing to do> with the SQL
-syntax C< SELECT foo AS bar > (see the documentation in
+syntax C< SELECT foo AS bar > (see the documentation in
L<DBIx::Class::ResultSet/ATTRIBUTES>). You can control the C<AS> part of the
generated SQL via the C<-as> field attribute as follows:
);
# Equivalent SQL
- # SELECT me.artistid, me.name, me.rank, me.charfield, COUNT( cds.cdid ) AS amount_of_cds
- # FROM artist me LEFT JOIN cd cds ON cds.artist = me.artistid
- # GROUP BY me.artistid, me.name, me.rank, me.charfield
- # ORDER BY amount_of_cds DESC
+ # SELECT me.artistid, me.name, me.rank, me.charfield, COUNT( cds.cdid ) AS amount_of_cds
+ # FROM artist me LEFT JOIN cd cds ON cds.artist = me.artistid
+ # GROUP BY me.artistid, me.name, me.rank, me.charfield
+ # ORDER BY amount_of_cds DESC
If your alias exists as a column in your base class (i.e. it was added with
my $schema = MySchema->connect("dbi:Pg:dbname=my_db");
- # Start a transaction. Every database change from here on will only be
+ # Start a transaction. Every database change from here on will only be
# committed into the database if the try block succeeds.
use Try::Tiny;
my $exception;
# next $thing
print "Cannot create thing: $_";
}
- # There was no error, so save all changes since the last
+ # There was no error, so save all changes since the last
# savepoint.
# SQL: RELEASE SAVEPOINT savepoint_0;
return $rv;
}
-=head2 Setting limit dialect for SQL::Abstract::Limit
-
-In some cases, SQL::Abstract::Limit cannot determine the dialect of
-the remote SQL server by looking at the database handle. This is a
-common problem when using the DBD::JDBC, since the DBD-driver only
-know that in has a Java-driver available, not which JDBC driver the
-Java component has loaded. This specifically sets the limit_dialect
-to Microsoft SQL-server (See more names in SQL::Abstract::Limit
--documentation.
-
- __PACKAGE__->storage->sql_maker->limit_dialect('mssql');
-
-The JDBC bridge is one way of getting access to a MSSQL server from a platform
-that Microsoft doesn't deliver native client libraries for. (e.g. Linux)
-
-The limit dialect can also be set at connect time by specifying a
-C<limit_dialect> key in the final hash as shown above.
-
=head2 Working with PostgreSQL array types
You can also assign values to PostgreSQL array columns by passing array
my $schema = My::Schema->connection('dbi:mysql:dbname=test',
$user, $pass,
{ mysql_enable_utf8 => 1} );
-
+
When set, a data retrieved from a textual column type (char,
varchar, etc) will have the UTF-8 flag turned on if necessary. This
=head2 Easy migration from class-based to schema-based setup
You want to start using the schema-based approach to L<DBIx::Class>
-(see L<SchemaIntro.pod>), but have an established class-based setup with lots
-of existing classes that you don't want to move by hand. Try this nifty script
-instead:
+(see L<DBIx::Class::Manual::Intro/Setting it up manually>), but have an
+established class-based setup with lots of existing classes that you don't
+want to move by hand. Try this nifty script instead:
use MyDB;
use SQL::Translator;
For example, say that you have three columns, C<id>, C<number>, and
C<squared>. You would like to make changes to C<number> and have
C<squared> be automagically set to the value of C<number> squared.
-You can accomplish this by overriding C<store_column>:
+You can accomplish this by overriding C<store_column> in your L<Result class|DBIx::Class::Manual::Glossary/Result class>:
sub store_column {
my ( $self, $name, $value ) = @_;
Note that the hard work is done by the call to C<next::method>, which
redispatches your call to store_column in the superclass(es).
+Generally, if this is a calculation your database can easily do, try
+and avoid storing the calculated value, it is safer to calculate when
+needed, than rely on the data being in sync.
+
=head2 Automatically creating related objects
You might have a class C<Artist> which has many C<CD>s. Further, you
sub query_start {
my $self = shift();
my $sql = shift();
- my $params = @_;
+ my @params = @_;
$self->print("Executing $sql: ".join(', ', @params)."\n");
$start = time();
If using L<create|DBIx::Class::ResultSet/create> instead, use a transaction and
commit every C<X> rows; where C<X> gives you the best performance without
-locking the table for too long.
+locking the table for too long.
=item *
projects / dbsrgits/DBIx-Class.git / blobdiff