NAME¶
Data::Phrasebook::SQL - The SQL/DBI Phrasebook Model.
SYNOPSIS¶
use Data::Phrasebook;
use DBI;
my $dbh = DBI->connect(...);
my $book = Data::Phrasebook->new(
class => 'SQL',
dbh => $dbh,
file => 'queries.txt',
);
my $q = $book->query( 'find_author', {
author => "Lance Parkin"
});
while ( my $row = $q->fetchrow_hashref ) {
print "He wrote $row->{title}\n";
}
$q->finish;
queries.txt:
find_author=select title,author from books where author = :author
DESCRIPTION¶
In order to make use of features like placeholders in DBI in conjunction with
phrasebooks, it's helpful to have a phrasebook be somewhat more aware of how
DBI operates. Thus, you get "Data::Phrasebook::SQL".
"Data::Phrasebook::SQL" has knowledge of how DBI works and creates and
executes your queries appropriately.
CONSTRUCTOR¶
new¶
Not to be accessed directly, but via the parent Data::Phrasebook, by specifying
the class as SQL.
Additional arguments to those described in Data::Phrasebook::Generic are:
- •
- "dbh" - a DBI database handle.
METHODS¶
dbh¶
Set, or get, the current DBI handle.
query¶
Constructs a Data::Phrasebook::SQL::Query object from a template. Takes at least
one argument, this being the identifier for the query. The identifier is used
as a key into the phrasebook "file". A second argument can be
provided, which is an optional hashref of key to value mappings.
If phrasebook has a YAML source looking much like the following:
---
find_author:
sql: select class,title,author from books where author = :author
You could write:
my $q = $book->query( 'find_author' );
OR
my $q = $book->query( 'find_author', {
author => 'Lance Parkin'
} );
OR
my $author = 'Lance Parkin';
my $q = $book->query( 'find_author', {
author => \$author,
} );
# sql = select class,title,author from books where author = ?
# args = 'Lance Parkin'
In the above examples, the parameters are bound to the SQL using the bind
parameters functionality. This is more efficient in most cases where the same
SQL is reused with different values for fields.
However, not all SQL statements just need to bind parameters, some may require
the ability to replace parameters, such as a field list.
---
find_author:
sql: select :fields from books where author = :author
my $q = $book->query( 'find_author',
replace => { fields => 'class,title,author' },
bind => { author => 'Lance Parkin' }
);
# sql = select class,title,author from books where author = ?
# args = 'Lance Parkin'
In all instances, if the SQL template requested does not exist or has no
definition, then an error will be thrown.
Consult Data::Phrasebook::SQL::Query for what you can then do with your returned
object.
For reference: the bind hashref argument, if it is given, is given to the query
object's "order_args" and then "args" methods.
SEE ALSO¶
Data::Phrasebook, Data::Phrasebook::Generic, Data::Phrasebook::SQL::Query.
SUPPORT¶
Please see the README file.
AUTHOR¶
Original author: Iain Campbell Truskett (16.07.1979 - 29.12.2003)
Maintainer: Barbie <barbie@cpan.org> since January 2004.
for Miss Barbell Productions <http://www.missbarbell.co.uk>.
COPYRIGHT AND LICENSE¶
Copyright (C) 2003 Iain Truskett.
Copyright (C) 2004-2010 Barbie for Miss Barbell Productions.
This module is free software; you can redistribute it and/or
modify it under the Artistic Licence v2.