NAME

Class::AutoDB::Collection - Schema information for one collection

SYNOPSIS

This is a helper class for Class::AutoDB::Registry which represents the schema information for one collection.

use Class::AutoDB::Registration;
use Class::AutoDB::Collection;
my $registration=new Class::AutoDB::Registration
  (-class=>'Person',
   -collection=>'Person',
   -keys=>qq(name string, dob integer, significant_other object, 
             friends list(object)),
   -transients=>[qw(age)],
   -auto_gets=>[qw(significant_other)]);

my $collection=new Class::AutoDB::Collection
  (-name=>'Person',-register=>$registration);

# Get the object's attributes
my $name=$collection->name; 
my $keys=$collection->keys;            # hash of key=>type pairs
my $tables=$collection->tables;        # Class::AutoDB::Table objects 
                                       #   that implement this collection 

my @sql=$collection->schema;           # SQL statements to create collection
my @sql=$collection->schema('create'); # same as above
my @sql=$collection->schema('drop');   # SQL statements to drop collection
my @sql=$collection->schema('alter',$diff); 
                                       # SQL statements to alter collection
                                       #   ($diff is CollectionDiff object)

DESCRIPTION

This class represents processed registration information for one collection. Registrations are fed into the class via the 'register' method which combines the information to obtain a single hash of key=>type pairs. It makes sure that if the same key is registered multiple times, it has the same type each time. It further processes the information to determine the database tables needed to implement the collection, and the SQL statements needed to create, and drop those tables. It also has the ability to compare its current state to a Class::AutoDB::CollectionDiff object and generate the SQL statements needed to alter the current schema the new one.

This class does not talk to the database.

BUGS and WISH-LIST

Name

Description

Priority/When

Schema alter

schema('alter') included for completeness, but probably doesn't produce the correct SQL, and seems not to be used. Should fix or trash.

Wish-list

METHODS and FUNCTIONS - Initialization

Title

new

Usage

my $collection=new Class::AutoDB::Collection
  (-name=>'Person',
   -register=>$registration);

Function

Constructor.

Args

-name

Name of collection being registered

-register

One Class::AutoDB::Registration object or an ARRAY ref of same for this collection

Returns

Collection object

METHODS and FUNCTIONS – Simple Attributes

These are methods for getting and setting the values of simple attributes. Methods have the same name as the attribute. Some of these should be read-only (more precisely, should only be written by code internal to the object), but this is not enforced.

To get the value of attribute xxx, just say

$xxx=$object->xxx;

To set an attribute, say

$object->xxx($new_value);

To clear it, say

$object->xxx(undef);

Attribute

name

Function

Collection name

Access

Read-only

METHODS and FUNCTIONS – Manage registrations

Title

register

Usage

$collection->register($registration)

$collection->register($registration1,$registration2)

$collection->register($registrations)

Function

Set registration objects for this collection.

Args

$registration

One or more Class:AutoDB::Registration objects

$registrations

ARRAY ref of Class:AutoDB::Registration objects

Returns

Nothing



Title

merge

Usage

$collection->merge($diff)

Function

Add search keys to collection as specified by diff.

Args

$diff

Class:AutoDB::CollectionDiff object comparing this collection to new on

Returns

Nothing

METHODS and FUNCTIONS – Other

Title

keys

Usage

my %keys=$collection->keys

my $keys=$collection->keys

my %keys=$collection->keys($keys)

my $keys=$collection->keys($keys)

Function

Get search keys for this collection. Used internally to set keys, but external programs should not attempt this as the keys are computed from the registrations.

Args

$keys

Search keys for collection. HASH ref of key=>type pairs

Returns

HASH or HASH ref depending on context



Title

tables

Usage

my @tables=$collection->tables

my $tables=$collection->tables

my @tables=$collection->tables($tables)

my $collections=$table->tables($tables)

Function

Get Class::AutoDB:Table objects for this collection. Used internally to set the tables, but external programs should not attempt this as the tables are computed from the registrations.

Args

$tables

ARRAY ref of Class::AutoDB:Table objects

Returns

ARRAY or ARRAY ref depending on context



Title

put

Usage

$collection->put($object)

Function

Returns SQL statements needed to store the object in the tables that implement the collection. Does not touch the database

Args

$object

Object to be stored.

Returns

ARRAY or ARRAY ref depending on context. Each element of the results is a single SQL statement as a string.



Title

create

Usage

$collection->create

Function

Returns SQL statements needed to create the tables that implement the collection. Does not touch the database

Args

none


Returns

ARRAY or ARRAY ref depending on context. Each element of the results is a single SQL statement as a string.



Title

drop

Usage

$collection->drop

Function

Returns SQL statements needed to drop the tables that implement the collection. Does not touch the database

Args

none


Returns

ARRAY or ARRAY ref depending on context. Each element of the results is a single SQL statement as a string.



Title

alter

Usage

$collection->alter($diff)

Function

Returns SQL statements needed to alter the tables that implement the collection. Does not touch the database

Args

$diff

Class:AutoDB::CollectionDiff object comparing this collection to new one.

Returns

ARRAY or ARRAY ref depending on context. Each element of the results is a single SQL statement as a string.