DBO is an ORM designed for convenience and ease of use, it is modeled after DBIx::* if you're into that kind of thing already (note: some concepts and names have deviated).
- relationships
- row object inflation (calling .first on a query returns a DBO::Row)
- row objects inherit from the model::@columns
- model level convenience methods
- row level convenience methods
- column type and data validation hooks
- decouple SQL generation from DBO::Searchable (this includes decoupling the SQL generation from the DB layer)
- look at YAML generation of models
- validation of model/table/relationships when model loads
- prefetch relationships option
- handle compounded primary keys
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).
use DBO::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
unit class X::Model::Customer does DBO::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.
class :: does DBO::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 DBO 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 DBO model returns an inflated object (:has-one) or a filterable object (:has-many).
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%' }, });
# later on ...
my $geo-filtered-customers = $customer.search({ country => 'usa' });
# $geo-filtered-customers effective filter is:
# {
# name => { like => '%bozo%' },
# country => 'usa',
# }
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.
Returns the first row (again, inflated ::Row::XYZ) and caches the prepared statement (this is destroyed and ignored if $next is falsey)
Same as calling .first(%filter, :next)
Returns the result of a select count for the current filter selection. Providing %filter results in .search(%filter).count
Deletes all rows matching criteria. Providing %filter results in .search(%filter).delete
Creates a new row with %field-data.
DBO::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 DBO::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 = 5A 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 DBO::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
Duplicates the row omitting the is-primary-key field so the subsequent .save results in a new row rather than updating
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
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
Retrieves the value for $key with any field changes having priority over data in database, use .is-dirty
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.
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