DB::Xoos::Pg

DB::Xoos::Pg is an ORM designed for convenience and ease of use. It is based upon DB::Xoos, provides roles and enhancements and allows you to connect to postgres for ultimate magic.

Usage

Below is a minimum viable model setup for your app. Xoos does not create the table for you, that is up to you.

autoloading models (only available in Pg at the moment)

lib/app.pm6

use DB::Xoos::Pg;

my DB::Xoos::Pg $d .=new;

$d.connect('pg://xyyz/example', options => { :dynamic-loading });

my $customer-model = $d.model('Customer');
my $new-customer   = $customer-model.new-row;
$new-customer.name('xyz co');
$new-customer.rate(150);
$new-customer.update; # runs an insert because this is a new row

my $xyz = $customer-model.search({ name => { 'like' => '%xyz%' } }).first;
$xyz.rate( $xyz.rate * 2 ); #twice the rate!
$xyz.update; # UPDATEs the database

my $xyz-orders = $xyz.orders.count;

same example with model modules

lib/app.pm6

use DB::Xoos::Pg;

my DB::Xoos::Pg $d .=new;

$d.connect('sqlite://xyz.sqlite3');

my $customer-model = $d.model('Customer');
my $new-customer   = $customer-model.new-row;
$new-customer.name('xyz co');
$new-customer.rate(150);
$new-customer.update; # runs an insert because this is a new row

my $xyz = $customer-model.search({ name => { 'like' => '%xyz%' } }).first;
$xyz.rate( $xyz.rate * 2 ); #twice the rate!
$xyz.update; # UPDATEs the database

my $xyz-orders = $xyz.orders.count;

lib/Model/Customer.pm6

use DB::Xoos::Role::Model;
unit class Model::Customer does DB::Xoos::Role::Model['customer'];

has @.columns = [
  id => {
    type           => 'integer',
    nullable       => False,
    is-primary-key => True,
    auto-increment => 1,
  },
  name => {
    type           => 'text',
  },
  rate => {
    type => 'integer',
  },
];

has @.relations = [
  orders => { :has-many, :model<Order>, :relate(id => 'customer_id') },
];

role DB::Xoos::Role::Model

What is a model? A model is essentially a table in your database. Your ::Model::X is pretty barebones, in this module you'll defined @.columns and @.relations (if there are any relations).

Example

use DB::Xoos::Role::Model;
# the second argument below is optional and also accepts a type.
# if the arg is omitted then it attempts to auto load ::Row::Customer
# if it fails to auto load then it uses an anonymous Row and adds convenience methods to that
unit class X::Model::Customer does DB::Xoos::Role::Model['customer', 'X::Row::Customer']; 

has @.columns = [
  id => {
    type           => 'integer',
    nullable       => False,
    is-primary-key => True,
    auto-increment => 1,
  },
  name => {
    type           => 'text',
  },
  contact => {
    type => 'text',
  },
  country => {
    type => 'text',
  },
];

has @.relations = [
  orders => { :has-many, :model<Order>, :relate(id => 'customer_id') },
  open_orders => { :has-many, :model<Order>, :relate(id => 'customer_id', '+status' => 'open') },
  completed_orders => { :has-many, :model<Order>, :relate(id => 'customer_id', '+status' => 'closed') },
];

# down here you can have convenience methods

method delete-all { #never do this in real life
  die '.delete-all disabled in prod or if %*ENV{in-prod} not defined'
    if !defined %*ENV{in-prod} || so %*ENV{in-prod};
  my $s = self.search({ id => { '>' => -1 } });
  $s.delete;
  !so $s.count;
}

In this example we're creating a customer model with columns id, name, contact, country and relations with specific filter criteria. You may notice the +status => 'open' on the open_orders relationship, the + here indicates it's a filter on the original table.

Breakdown

class :: does DB::Xoos::Role::Model['table-name', 'Optional String or Type'];

Here you can see the role accepts one or two parameters, the first is the DB table name, the latter is a String or Type of the row you'd like to use for this model. If no row is found then Xoos will create a generic row and add helper methods for you using the model's column data.

@.columns

A list of columns in the table. It is highly recommended you have one is-primary-key or .update will have unexpected results.

@.relations

This accepts a list of key values, the key defining the accessor name, the later a hash describing the relationship. :has-one and :has-many are both used to dictate whether a Xoos model returns an inflated object (:has-one) or a filterable object (:has-many).

Methods

search(%filter?, %options?)

Creates a new filterable model and returns that. Every subsequent call to .search will add to the existing filters and options the best it can.

Example:

my $customer = $dbo.model('Customer').search({
  name => { like => '%bozo%' }, 
}, {
  order-by => [ created_date => 'DESC', 'customer_name' ], 
});
# later on ...
my $geo-filtered-customers = $customer.search({ country => 'usa' });
# $geo-filtered-customers effective filter is:
#   {
#      name => { like => '%bozo%' },
#      country => 'usa',
#   }

.all(%filter?)

Returns all rows from query (an array of inflated ::Row::XYZ). Providing %filter is the same as doing .search(%filter).all and is provided only for convenience.

.first(%filter?, :$next = False)

Returns the first row (again, inflated ::Row::XYZ) and caches the prepared statement (this is destroyed and ignored if $next is falsey)

.next(%filter?)

Same as calling .first(%filter, :next)

.count(%filter?)

Returns the result of a select count for the current filter selection. Providing %filter results in .search(%filter).count

.delete(%filter?)

Deletes all rows matching criteria. Providing %filter results in .search(%filter).delete

.insert(%field-data?)

Creates a new row with %field-data.

Convenience methods

DB::Xoos::Role::Model inheritance allows you to have convenience methods, these methods can act on whatever the current set of filters is.

Consider the following:

Convenience model definition:

class X::Model::Customer does DB::Xoos::Role::Model['customer'];

# columns and relations

method remove-closed-orders {
  self.closed_orders.delete;
}

Later in your code:

my $customers = $dbo.model('Customer');

my $all-customers    = $customers.search({ id => { '>' => -1 } });
my $single-customers = $customers.search({ id => 5 });

$all-customers.remove-closed-orders;
# this removes all orders for customers with an id > -1
$single-customer.remove-closed-orders;
# this removes all orders for customers with id = 5

role DB::Xoos::Role::Row

A role to apply to your ::Row::Customer. If there is no ::Row::Customer a generic row is created using the column and relationship data specified in the corresponding Model and this file is only really necessary if you want to add convenience methods.

When a class :: does DB::Xoos::Role::Row, it receives the info from the model and adds the methods for setting/getting field data.

With the model definition above:

my $invoice-model = $dbo.model('invoice');
my $invoice = $invoice-model.new-row({
  customer_id => $customer.id,
  amount      => 400,
});  # this $invoice is NOT in the database until .update

my $old-amount = $invoice.amount; # = 400
$invoice.amount($invoice.amount * 2);
my $new-amount = $invoice.amount; # = 800

$invoice.update;

If there is a collision in the naming conventions between your model and the row then you'll need to use [set|get]-column

Methods

.duplicate

Duplicates the row omitting the is-primary-key field so the subsequent .save results in a new row rather than updating

.as-hash

Returns the current field data for the row as a hash. If there has been unsaved updates to fields then it returns those values instead of what is in the database. You can determine whether the row has field-changes with is-dirty

.set-column(Str $key, $value)

Updates the field data for the column (not stored in database until .update is called). If you want to .wrap a field setter for a certain key, wrap this and filter for the key

.get-column(Str $key)

Retrieves the value for $key with any field changes having priority over data in database, use .is-dirty

.get-relation(Str $column, :%spec?)

It is recommended any Model with a relationship name that conflicts and causes no convenience method to be generated be renamed, but use this if you must. $customer.orders is calling essentially $customer.get-relation('orders'). Do not provide %spec unless you know what you're doing.

.update

Saves the row in the database. If the field with a positive is-primary-key is set then it runs and UPDATE ... statement, otherwise it INSERT ...s and updates the Row's is-primary-key field. Ensure you set one field with is-primary-key

Field validation

It's just this easy:

has @.columns = [
  qw<...>,
  phone => {
    type     => 'text',
    validate => sub ($new-value) {
      # return Falsey value here for validation to fail
      #   Truthy value will cause validation to succeed
    },
  },
  qw<...>,
];