NAME

DB::Object::Fields - Tables Fields Object Accessor

SYNOPSIS

    my $dbh = DB::Object->connect({
    driver => 'Pg',
    conf_file => $conf,
    database => 'my_shop',
    host => 'localhost',
    login => 'super_admin',
    schema => 'auth',
    # debug => 3,
    }) || bailout( "Unable to connect to sql server on host localhost: ", DB::Object->error );
    my $tbl_object = $dbh->customers || die( "Unable to get the customers table object: ", $dbh->error, "\n" );
    my $fields = $tbl_object->fields;
    print( "Fields for table \"", $tbl_object->name, "\": ", Dumper( $fields ), "\n" );
    my $c = $tbl_object->fo->currency;
    print( "Got field object for currency: \"", ref( $c ), "\": '$c'\n" );
    printf( "Name: %s\n", $c->name );
    printf( "Type: %s\n", $c->type );
    printf( "Default: %s\n", $c->default );
    printf( "Position: %s\n", $c->pos );
    printf( "Table: %s\n", $c->table );
    printf( "Database: %s\n", $c->database );
    printf( "Schema: %s\n", $c->schema );
    printf( "Next field: %s (%s)\n", $c->next, ref( $c->next ) );
    print( "Showing name fully qualified: ", $c->prefixed( 3 )->name, "\n" );
    ## would print: my_shop.public.customers.currency
    print( "Trying again (should keep prefix): ", $c->name, "\n" );
    ## would print again: my_shop.public.customers.currency
    print( "Now cancel prefixing at the table fields level.\n" );
    $tbl_object->fo->prefixed( 0 );
    print( "Showing name fully qualified again (should not be prefixed): ", $c->name, "\n" );
    ## would print currency
    print( "First element is: ", $c->first, "\n" );
    print( "Last element is: ", $c->last, "\n" );

VERSION

    0.1

DESCRIPTION

The purpose of this module is to enable access to the table fields as DB::Object::Fields::Field objects.

The way this works is by having DB::Object::Tables fields_object or fo for short, dynamically create a class based on the database name and table name. For example if the database driver were PostgreSQL, the database were my_shop and the table customers, the dynamically created package would become DB::Object::Postgres::Tables::MyShop::Customers. This class would inherit from this package DB::Object::Fields.

Field objects can than be dynamically instantiated by accessing them, such as (assuming the table object $tbl_object here represent the table customers) $tbl_object-fo->last_name>. This will return a DB::Object::Fields::Field object.

A note on the design: there had to be a separate this separate package DB::Object::Fields, because access to table fields is done through the AUTOLOAD and the methods within the package DB::Object::Tables and its inheriting packages would clash with the tables fields. This package has very few methods, so the risk of a sql table field clashing with a method name is very limited. In any case, if you have in your table a field with the same name as one of those methods here (see below for the list), then you can instantiate a field object with:

    $tbl_object->_initiate_field_object( 'last_name' );

CONSTRUCTOR

new( %arg )

Creates a new DB::Object::Fields objects. It may also take an hash like arguments, that also are method of the same name.

debug

Toggles debug mode on/off

METHODS

_initiate_field_object()
database_object()
init()
prefixed()
table_object()

AUTHOR

Jacques Deguest <jack@deguest.jp>

SEE ALSO

perl

COPYRIGHT & LICENSE

Copyright (c) 2020 DEGUEST Pte. Ltd.

All rights reserved

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.