Matthew Simon Cavalletto

NAME

DBIx::SQLEngine::Record::Base - Base Class for Records

SYNOPSIS

Setup: Several ways to create a class.

  my $sqldb = DBIx::SQLEngine->new( ... );

  $class_name = $sqldb->record_class( $table_name );
  
  $sqldb->record_class( $table_name, $class_name);
  
  package My::Record;
  use DBIx::SQLEngine::Record::Class '-isasubclass';  
  My::Record->table( $sqldb->table($table_name) );

Basics: Common operations on a record.

  $record = $class_name->select_record( $primary_key );
  
  @records = $class_name->fetch_select(%clauses)->records;
  
  $record = $class_name->new_with_values(somefield => 'My Value');
  
  print $record->get_values( 'somefield' );
  $record->change_values( somefield => 'New Value' );

  $record->insert_record();
  
  $record->update_record();
  
  $record->delete_record();

Schema: Access to table and columns.

  unless ( $class_name->table_exists ) {
    $class_name->create_table( { name => 'id', type => 'int'} );
  }

DESCRIPTION

DBIx::SQLEngine::Record::Base is a superclass for database records in tables accessible via DBIx::SQLEngine.

By subclassing this package, you can easily create a class whose instances represent each of the rows in a SQL database table.

TABLE INTERFACE

Each record class is associated with a table object. The table provides the DBI connection and SQL execution capabilities required to talk to the remote data storage.

Table Accessor

table()
  $class_name->table() : $table
  $class_name->table($table)

Get and set our current DBIx::SQLEngine::Schema::Table. Required value. Establishes the table a specific class of record will be stored in.

get_table()
  $class_name->get_table() : $table or exception

Returns the table, or throws an exception if it is not set.

Methods Delegated to Table

These methods all call the same method on the associated table.

detect_sqlengine()
  $class_name->detect_sqlengine : $flag

Detects whether the SQL database is avaialable by attempting to connect.

table_exists()
  $class_name->table_exists : $flag

Detects whether the table has been created and has not been dropped.

columnset()
  $class_name->columnset () : $columnset

Returns the current columnset, if any.

fetch_one_value()
  $class_name->fetch_one_value( %sql_clauses ) : $scalar

Calls fetch_select, then returns the first value from the first row of results.

count_rows()
  $class_name->count_rows ( ) : $number
  $class_name->count_rows ( $criteria ) : $number

Return the number of rows in the table. If called with criteria, returns the number of matching rows.

Table Delegation Methods

The following methods are used internally to facilitate delegation to the table object.

table_fetch_one_method()
  $class->table_fetch_one_method( $method, @args );

Calls the named method on the table and inflates the result with record_from_table.

table_fetch_set_method()
  $class->table_fetch_set_method( $method, @args );

Calls the named method on the table and inflates the result with record_set_from_table.

table_record_method()
  $record->table_record_method( $method, @args );

Calls the named method on the table, passing the record itself as the first argument.

SIMPLE RECORD INTERFACE

Constructor

You may create your own records for new instances, or fetch records from the database as described in "FETCHING DATA (SQL DQL)"

new_empty_record()
  $class_name->new_empty_record() : $empty_record

Creates and blesses an empty hash object into the given record class.

new_with_values()
  $class_name->new_with_values ( %key_argument_pairs ) : $record

Calls new_empty_record, and then change_values.

new_copy()
  $record->new_copy() : $new_record
  $record->new_copy( %key_argument_pairs ) : $new_record

Makes a copy of a record and then clears its primary key so that it will be recognized as a distinct, new row in the database rather than overwriting the original when you save it. Also includes any provided arguments in its call to new_with_values.

Simple Fetch and Save

These methods hide the distinctions between fetch/create and insert/update.

get_record()
  $class_name->get_record ( ) : $new_empty_record
  $class_name->get_record ( $p_key ) : $fetched_record_or_undef

Calls new if no primary key is provided, or if the primary key is zero; otherwise calls select_record.

save_record()
  $record->save_record () : $record_or_undef

Determines whether the record has an primary key assigned to it and then calls either insert_record or update_record. Returns the record unless it fails to save it.

Getting and Changing Values

Records are stored as simple hashes, and their contents can be accessed that way, but methods are also available to get and set field values.

get_values()
  $record->get_values( key1 ) : $value
  $record->get_values( key1, key2, ... ) : $values_joined_with_comma
  $record->get_values( key1, key2, ... ) : @values

Returns the values associated with the keys in the provided record.

change_values()
  $record->change_values( key1 => value1, ... ) 

Sets the associated key-value pairs in the provided record.

hash_from_record()
  $record->hash_from_record() : $hash_ref
  $record->hash_from_record() : %hash_values

Returns an unblessed copy of the values in the record.

Primary Keys

primary_criteria()
  $record->primary_criteria() : $hash_ref

Returns a hash of key-value pairs which could be used to select this record by its primary key.

primary_key_value()
  $record->primary_key_value() : $id_value

Returns the primary key value for this object.

Change and Save Combinations

change_and_save()
  $record->change_and_save ( %key_argument_pairs ) : $record

Calls change_values, and then save_record.

new_and_save()
  $class_name->new_and_save ( %key_argument_pairs ) : $record

Calls new_empty_record, and then change_and_save.

Destruction

DESTROY()
  $record->DESTROY()

For internal use only. Does nothing. Subclasses can override this with any functions they wish called when an individual record is being garbage collected.

FETCHING DATA (SQL DQL)

Select to Retrieve Records

fetch_select()
  $class_name->fetch_select ( %select_clauses ) : $record_set

Retrives records from the table using the provided SQL select clauses.

Calls the corresponding SQLEngine method with the table name and the provided arguments. Each row hash is blessed into the record class before being wrapped in a Record::Set object.

fetch_one_record()
  $sqldb->fetch_one_record( %select_clauses ) : $record_hash

Retrives one record from the table using the provided SQL select clauses.

Calls fetch_select, then returns only the first row of results. The row hash is blessed into the record class before being returned.

select_record()
  $class_name->select_record ( $primary_key_value ) : $record_obj
  $class_name->select_record ( \@compound_primary_key ) : $record_obj
  $class_name->select_record ( \%hash_with_primary_key_value ) : $record_obj

Fetches a single record by primary key.

The row hash is blessed into the record class before being returned.

select_records()
  $class_name->select_records ( @primary_key_values_or_hashrefs ) : $record_set

Fetches a set of one or more records by primary key.

Each row hash is blessed into the record class before being wrapped in a Record::Set object.

visit_select()
  $class_name->visit_select ( $sub_ref, %select_clauses ) : @results
  $class_name->visit_select ( %select_clauses, $sub_ref ) : @results

Calls the provided subroutine on each matching record as it is retrieved. Returns the accumulated results of each subroutine call (in list context).

Each row hash is blessed into the record class before being the subroutine is called.

Vivifying Records From The Database

These methods are called internally by the various select methods and do not need to be called directly.

record_from_table()
  $class_name->record_from_table( $hash_ref )
  $class_name->record_from_table( $hash_ref ) : $record
  $class_name->record_from_table( %hash_contents ) : $record

Converts a hash retrieved from the table to a Record object.

record_set_from_table()
  $class_name->record_set_from_table( $hash_array_ref )
  $class_name->record_set_from_table( $hash_array_ref ) : $record_set
  $class_name->record_set_from_table( @hash_refs ) : $record_set

Converts an array of hashrefs retrieved from the table to a Record::Set object containing Record objects.

EDITING DATA (SQL DML)

Insert to Add Records

After constructing a record with one of the new_*() methods, you may save any changes by calling insert_record.

insert_record()
  $record_obj->insert_record() : $flag

Adds the values from this record to the table. Returns the number of rows affected, which should be 1 unless there's an error.

Update to Change Records

After retrieving a record with one of the fetch methods, you may save any changes by calling update_record.

update_record()
  $record_obj->update_record() : $record_count

Attempts to update the record using its primary key as a unique identifier. Returns the number of rows affected, which should be 1 unless there's an error.

Delete to Remove Records

delete_record()
  $record_obj->delete_record() : $record_count

Delete this existing record based on its primary key. Returns the number of rows affected, which should be 1 unless there's an error.

Mixin Class Redispatch

NEXT

Enhanced superclass method dispatch for use inside mixin class methods. Allows mixin classes to redispatch to other classes in the inheritance tree without themselves inheriting from anything.

(This is similar to the functionality provided by NEXT::ACTUAL, but without using AUTOLOAD; for a more generalized approach to this issue see NEXT.)

SEE ALSO

For more about the Record classes, see DBIx::SQLEngine::Record::Class.

See DBIx::SQLEngine for the overall interface and developer documentation.

See DBIx::SQLEngine::Docs::ReadMe for general information about this distribution, including installation and license information.