Model Metadata¶

Overview¶

When using Phalcon\Mvc\Model classes, which correspond to actual tables in the database, Phalcon needs to know essential information regarding those tables, such as fields, data types, primary and foreign keys as well as relationships. The Phalcon\Mvc\Model\MetaData object is offering this functionality, transparently querying the database and generating the necessary data from the database schema. The data can then be stored in a data store (such as Redis, APCu etc.) to ensure that the database is not queried for the schema every time a query is executed.

NOTE

During deployments to production, please ensure that you always invalidate the metaData cache so that database changes that propagated during your deployment are available in your application. The metaData cache will be rebuilt with all the necessary changes.

<?php

use MyApp\Models\Invoices;
use Phalcon\Mvc\Model\MetaData;

$invoice = new Invoices();

/** @var MetaData\ $metadata */
$metadata = $invoice->getModelsMetaData();

$attributes = $metadata->getAttributes($invoice);
print_r($attributes);

$dataTypes = $metadata->getDataTypes($invoice);
print_r($dataTypes);

The above code will print the field names and also the fields to field types array. We use attributes as an alias of fields.

[
    [0] => inv_id
    [1] => inv_cst_id
    [2] => inv_status_flag
    [3] => inv_title
    [4] => inv_total
    [5] => inv_created_at
    [6] => inv_created_by
    [7] => inv_updated_at
    [8] => inv_updated_by
]

[
    [inv_id]          => 0,
    [inv_cst_id]      => 0,
    [inv_status_flag] => 0,
    [inv_title]       => 2,
    [inv_total]       => 0,
    [inv_created_at]  => 4,
    [inv_created_by]  => 0,
    [inv_updated_at]  => 4,
    [inv_updated_by]  => 0,
]

Constants¶

Phalcon\Mvc\Model\MetaData exposes a number of constants that can be used to retrieve attributes from the internal collection.

Name	Description
`MODELS_ATTRIBUTES`	Every column in the mapped table
`MODELS_AUTOMATIC_DEFAULT_INSERT`	Fields that must be ignored from `INSERT` SQL statements
`MODELS_AUTOMATIC_DEFAULT_UPDATE`	Fields that must be ignored from `UPDATE` SQL statements
`MODELS_COLUMN_MAP`	Column map (aliases)
`MODELS_DATA_TYPES`	Every column and its data type
`MODELS_DATA_TYPES_BIND`	How every column must be bound/casted
`MODELS_DATA_TYPES_NUMERIC`	The columns that have numeric data types
`MODELS_DEFAULT_VALUES`	Default values for columns
`MODELS_EMPTY_STRING_VALUES`	Columns that allow empty strings
`MODELS_IDENTITY_COLUMN`	The identity column. `false` if the model does not have an identity column
`MODELS_NON_PRIMARY_KEY`	Every column that is not part of the primary key
`MODELS_NOT_NULL`	Every column that does not allow `null` values
`MODELS_PRIMARY_KEY`	Every column part of the primary key
`MODELS_REVERSE_COLUMN_MAP`	Reverse column map (aliases)

Methods¶

public function getAttributes(ModelInterface $model): array

Returns table attributes names (fields)

print_r(
    $metaData->getAttributes(
        new Invoices()
    )
);

public function getAutomaticCreateAttributes(
    ModelInterface $model
): array

Returns attributes that must be ignored from the INSERT SQL generation

print_r(
    $metaData->getAutomaticCreateAttributes(
        new Invoices()
    )
);

public function getAutomaticUpdateAttributes(
    ModelInterface $model
): array

Returns attributes that must be ignored from the UPDATE SQL generation

print_r(
    $metaData->getAutomaticUpdateAttributes(
        new Invoices()
    )
);

public function getBindTypes(ModelInterface $model): array

Returns attributes and their bind data types

print_r(
    $metaData->getBindTypes(
        new Invoices()
    )
);

public function getColumnMap(ModelInterface $model): array

Returns the column map if any

print_r(
    $metaData->getColumnMap(
        new Invoices()
    )
);

public function getDefaultValues(ModelInterface $model): array

Returns attributes (which have default values) and their default values

 print_r(
     $metaData->getDefaultValues(
         new Invoices()
     )
 );

public function getDataTypes(ModelInterface $model): array

Returns attributes and their data types

print_r(
    $metaData->getDataTypes(
        new Invoices()
    )
);

public function getDataTypesNumeric(ModelInterface $model): array

Returns attributes which types are numerical

print_r(
    $metaData->getDataTypesNumeric(
        new Invoices()
    )
);

public function getEmptyStringAttributes(
    ModelInterface $model
): array

Returns attributes allow empty strings

print_r(
    $metaData->getEmptyStringAttributes(
        new Invoices()
    )
);

public function getIdentityField(ModelInterface $model): string

Returns the name of identity field (if one is present)

print_r(
    $metaData->getIdentityField(
        new Invoices()
    )
);

public function getNonPrimaryKeyAttributes(
    ModelInterface $model
): array

Returns an array of fields which are not part of the primary key

print_r(
    $metaData->getNonPrimaryKeyAttributes(
        new Invoices()
    )
);

public function getNotNullAttributes(ModelInterface $model): array

Returns an array of not null attributes

print_r(
    $metaData->getNotNullAttributes(
        new Invoices()
    )
);

public function getPrimaryKeyAttributes(
    ModelInterface $model
): array

Returns an array of fields which are part of the primary key

print_r(
    $metaData->getPrimaryKeyAttributes(
        new Invoices()
    )
);

public function getReverseColumnMap(
    ModelInterface $model
): array

Returns the reverse column map if any

print_r(
    $metaData->getReverseColumnMap(
        new Invoices()
    )
);

public function getStrategy(): StrategyInterface

Return the strategy to obtain the meta-data

public function hasAttribute(
    ModelInterface $model, 
    string $attribute
): bool

Check if a model has certain attribute

print_r(
    $metaData->hasAttribute(
        new Invoices(),
        "inv_title"
    )
);

public function isEmpty(): bool

Checks if the internal meta-data container is empty

print_r(
    $metaData->isEmpty()
);

public function read(string $key): array | null

Reads metadata from the adapter

final public function readColumnMap(
    ModelInterface $model
): array | null

Reads the ordered/reversed column map for certain model

print_r(
    $metaData->readColumnMap(
        new Invoices()
    )
);

final public function readColumnMapIndex(
    ModelInterface $model, 
    int $index
)

Reads column-map information for certain model using a MODEL_* constant

print_r(
    $metaData->readColumnMapIndex(
        new Invoices(),
        MetaData::MODELS_REVERSE_COLUMN_MAP
    )
);

final public function readMetaData(ModelInterface $model): array

Reads the complete meta-data for certain model

print_r(
    $metaData->readMetaData(
        new Invoices()
    )
);

final public function readMetaDataIndex(
    ModelInterface $model, 
    int $index
)

Reads meta-data for certain model

print_r(
    $metaData->readMetaDataIndex(
        new Invoices(),
        0
    )
);

public function reset(): void

Resets internal meta-data in order to regenerate it

 $metaData->reset();

public function setAutomaticCreateAttributes(
    ModelInterface $model, 
    array $attributes
): void

Set the attributes that must be ignored from the INSERT SQL generation

$metaData->setAutomaticCreateAttributes(
    new Invoices(),
    [
        "inv_created_at" => true,
    ]
);

public function setAutomaticUpdateAttributes(
    ModelInterface $model, 
    array $attributes
): void

Set the attributes that must be ignored from the UPDATE SQL generation

$metaData->setAutomaticUpdateAttributes(
    new Invoices(),
    [
        "inv_updated_at" => true,
    ]
);

public function setEmptyStringAttributes(
    ModelInterface $model, 
    array $attributes
): void

Set the attributes that allow empty string values

$metaData->setEmptyStringAttributes(
    new Invoices(),
    [
        "inv_title" => true,
    ]
);

public function setStrategy(StrategyInterface $strategy): void

Set the meta-data extraction strategy

public function write(string $key, array $data): void

Writes the metadata to adapter

final public function writeMetaDataIndex(
    ModelInterface $model, 
    int $index, 
    mixed $data
): void

Writes meta-data for certain model using a MODEL_* constant

print_r(
    $metaData->writeColumnMapIndex(
        new Invoices(),
        MetaData::MODELS_REVERSE_COLUMN_MAP,
        [
            "title" => "inv_title",
        ]
    )
);

final protected function initialize(
    ModelInterface $model, 
    mixed $key, 
    mixed $table, 
    mixed $schema
)

Initialize the metadata for certain table

Adapters¶

Retrieving the metadata is an expensive database operation and we certainly do not want to perform it every time we run a query. We can however use one of many adapters available in order to cache the metadata.

NOTE

For local development, the Phalcon\Mvc\Models\MetaData\Memory adapter is recommended so that any changes to the database can be reflected immediately.

Adapter	Description
Phalcon\Mvc\Models\MetaData\Apcu	This adapter uses the Alternative PHP Cache (APC) to store the table metadata. (production)
Phalcon\Mvc\Models\MetaData\Libmemcached	This adapter uses the Memcached Server to store the table metadata. (production)
Phalcon\Mvc\Models\MetaData\Memory	This adapter uses memory. The metadata is cached only during the request. (development)
Phalcon\Mvc\Models\MetaData\Redis	This adapter uses Redis to store the table metadata. (production)
Phalcon\Mvc\Models\MetaData\Stream	This adapter uses plain files to store metadata. (not for production)

APCu¶

This adapter uses the Alternative PHP Cache (APC) to store the table metadata. The extension must be present in your system for this metadata cache to work. If the server is restarted, the data will be lost. This adapter is suitable for production applications.

The adapter receives a Phalcon\Cache\AdapterFactory class in order to instantiate the relevant cache object. You can also pass an array with additional options for the cache to operate.

The default prefix is ph-mm-apcu- and the lifetime is 172,000 (48 hours).

<?php

use Phalcon\Cache\AdapterFactory;
use Phalcon\Di\FactoryDefault;
use Phalcon\Mvc\Model\MetaData\Apcu;
use Phalcon\Storage\SerializerFactory;

$container = new FactoryDefault();
$container->set(
    'modelsMetadata',
    function () {
        $serializerFactory = new SerializerFactory();
        $adapterFactory    = new AdapterFactory($serializerFactory);
        $options = [
            'lifetime' => 86400,
            'prefix'   => 'my-prefix',
        ];

        return new Apcu($adapterFactory, $options);
    }
);

Libmemcached¶

This adapter uses the Memcached Server to store the table metadata. The extension must be present in your system for this metadata cache to work. This adapter is suitable for production applications.

The adapter receives a Phalcon\Cache\AdapterFactory class in order to instantiate the relevant cache object. You can also pass an array with additional options for the cache to operate.

The default prefix is ph-mm-memc- and the lifetime is 172,000 (48 hours). The persistenId is preset to php-mm-mcid-.

<?php

use Phalcon\Cache\AdapterFactory;
use Phalcon\Di\FactoryDefault;
use Phalcon\Mvc\Model\MetaData\Libmemcached;
use Phalcon\Storage\SerializerFactory;

$container = new FactoryDefault();
$container->set(
    'modelsMetadata',
    function () {
        $serializerFactory = new SerializerFactory();
        $adapterFactory    = new AdapterFactory($serializerFactory);
        $options = [
            'servers' => [
                0 => [
                    'host'   => '127.0.0.1',
                    'port'   => 11211,
                    'weight' => 1
                ],   
            ],
            'lifetime' => 86400,
            'prefix'   => 'my-prefix',
        ];

        return new Libmemcached($adapterFactory, $options);
    }
);

Memory¶

This adapter uses the server's memory to store the metadata cache. The cache is available only during the request, and then the cache is lost. This cache is more suitable for development, since it accommodates the frequent changes in the database during development.

<?php

use Phalcon\Di\FactoryDefault;
use Phalcon\Mvc\Model\MetaData\Memory;

$container = new FactoryDefault();
$container->set(
    'modelsMetadata',
    function () {
        return new Memory();
    }
);

Redis¶

This adapter uses the Redis to store the table metadata. The extension must be present in your system for this metadata cache to work. This adapter is suitable for production applications.

The adapter receives a Phalcon\Cache\AdapterFactory class in order to instantiate the relevant cache object. You can also pass an array with additional options for the cache to operate.

The default prefix is ph-mm-reds- and the lifetime is 172,000 (48 hours).

<?php

use Phalcon\Cache\AdapterFactory;
use Phalcon\Di\FactoryDefault;
use Phalcon\Mvc\Model\MetaData\Redis;
use Phalcon\Storage\SerializerFactory;

$container = new FactoryDefault();
$container->set(
    'modelsMetadata',
    function () {
        $serializerFactory = new SerializerFactory();
        $adapterFactory    = new AdapterFactory($serializerFactory);
        $options = [
            'host'     => '127.0.0.1',
            'port'     => 6379,
            'index'    => 1,
            'lifetime' => 86400,
            'prefix'   => 'my-prefix',
        ];

        return new Redis($adapterFactory, $options);
    }
);

Stream¶

This adapter uses the file system to store the table metadata. This adapter is suitable for production applications but not recommended since it introduces an increase in I/O.

The adapter can accept a metaDadaDir option with a directory on where the metadata will be stored. The default directory is the current directory.

<?php

use Phalcon\Di\FactoryDefault;
use Phalcon\Mvc\Model\MetaData\Stream;

$container = new FactoryDefault();
$container->set(
    'modelsMetadata',
    function () {
        $options = [
            'metaDataDir' => '/app/storage/cache/metaData',
        ];

        return new Stream($options);
    }
);

You can use the orm.exception_on_failed_metadata_save option in your php.ini file to force the component to throw an exception if there is an error storing the metadata or if the target directory is not writeable.

orm.exception_on_failed_metadata_save = true

Strategies¶

The default strategy to obtain the model's metadata is database introspection. Using this strategy, the information schema is used to identify the fields in a table, its primary key, nullable fields, data types, etc.

<?php

use Phalcon\Cache\AdapterFactory;
use Phalcon\Di\FactoryDefault;
use Phalcon\Mvc\Model\MetaData\Apcu;
use Phalcon\Mvc\Model\MetaData\Strategy\Introspection;
use Phalcon\Storage\SerializerFactory;

$container = new FactoryDefault();
$container->set(
    'modelsMetadata',
    function () {
        $serializerFactory = new SerializerFactory();
        $adapterFactory    = new AdapterFactory($serializerFactory);
        $options = [
            'lifetime' => 86400,
            'prefix'   => 'my-prefix',
        ];

        $metadata = new Apcu($adapterFactory, $options);
        $metadata->setStrategy(new Introspection());

        return $metadata;
    }
);

Introspection¶

This strategy does not require any customization and is implicitly used by all the metadata adapters.

Annotations¶

This strategy makes use of annotations to describe the columns in a model.

<?php

use Phalcon\Mvc\Model;

class Invoices extends Model
{
    /**
     * @Primary
     * @Identity
     * @Column(type='integer', nullable=false)
     */
    public $inv_id;

    /**
     * @Column(type='integer', nullable=false)
     */
    public $inv_cst_id;

    /**
     * @Column(type='string', length=70, nullable=false)
     */
    public $inv_title;

    /**
     * @Column(type='double', nullable=false)
     */
    public $inv_total;
}

Annotations must be placed in properties that are mapped to columns in the mapped source. Properties without the @Column annotation are handled as simple class attributes.

The following annotations are supported:

Name	Description
`@Primary`	Mark the field as part of the table's primary key
`@Identity`	The field is an auto_increment/serial column
`@Column`	This marks an attribute as a mapped column

The annotation @Column supports the following parameters:

Name	Description
`column`	Real column name
`type`	The column's type: `char`, `biginteger`, `blob`, `boolean`, `date`, `datetime`, `decimal`, `integer`, `float`, `json`, `longblob`, `mediumblob`, `timestamp`, `tinyblob`, `text`, `varchar`/`string` (default)
`length`	The column's length if any
`nullable`	Set whether the column accepts `null` values or not
`skip_on_insert`	Skip this column on insert
`skip_on_update`	Skip this column on updates
`allow_empty_string`	Column allow empty strings
`default`	Default value

The annotations strategy could be set up as follows:

<?php

use Phalcon\Cache\AdapterFactory;
use Phalcon\Di\FactoryDefault;
use Phalcon\Mvc\Model\MetaData\Apcu;
use Phalcon\Mvc\Model\MetaData\Strategy\Annotations;
use Phalcon\Storage\SerializerFactory;

$container = new FactoryDefault();
$container->set(
    'modelsMetadata',
    function () {
        $serializerFactory = new SerializerFactory();
        $adapterFactory    = new AdapterFactory($serializerFactory);
        $options = [
            'lifetime' => 86400,
            'prefix'   => 'my-prefix',
        ];

        $metadata = new Apcu($adapterFactory, $options);
        $metadata->setStrategy(new Annotations());

        return $metadata;
    }
);

Manual¶

Using the introspection strategies presented above, Phalcon can obtain the metadata for each model automatically. However, you have the option to define the metadata manually. This strategy overrides any strategy that has been set on the metadata manager. Columns added, modified or removed from the mapped table must be manually updated in the model for everything to work properly.

To set the metadata, we use the metaData method in a model:

<?php

use Phalcon\Mvc\Model;
use Phalcon\Db\Column;
use Phalcon\Mvc\Model\MetaData;

class Invoices extends Model
{
    public function metaData()
    {
        return array(
            MetaData::MODELS_ATTRIBUTES => [
                'inv_id',
                'inv_cst_id',
                'inv_status_flag',
                'inv_title',
                'inv_total',
                'inv_created_at',
                'inv_created_by',
                'inv_updated_at',
                'inv_updated_by',
            ],

            MetaData::MODELS_PRIMARY_KEY => [
                'inv_id',
            ],

            MetaData::MODELS_NON_PRIMARY_KEY => [
                'inv_cst_id',
                'inv_status_flag',
                'inv_title',
                'inv_total',
                'inv_created_at',
                'inv_created_by',
                'inv_updated_at',
                'inv_updated_by',
            ],

            MetaData::MODELS_NOT_NULL => [
                'inv_id',
                'inv_cst_id',
                'inv_status_flag',
                'inv_title',
                'inv_total',
                'inv_created_at',
                'inv_created_by',
                'inv_updated_at',
                'inv_updated_by',

            MetaData::MODELS_DATA_TYPES => [
                'inv_id'          => Column::TYPE_INTEGER,
                'inv_cst_id'      => Column::TYPE_INTEGER,
                'inv_status_flag' => Column::TYPE_INTEGER,
                'inv_title'       => Column::TYPE_VARCHAR,
                'inv_total'       => Column::TYPE_FLOAT,
                'inv_created_at'  => Column::TYPE_DATETIME,
                'inv_created_by'  => Column::TYPE_INTEGER,
                'inv_updated_at'  => Column::TYPE_DATETIME,
                'inv_updated_by'  => Column::TYPE_INTEGER,
            ],

            MetaData::MODELS_DATA_TYPES_NUMERIC => [
                'inv_id'          => true,
                'inv_cst_id'      => true,
                'inv_status_flag' => true,
                'inv_total'       => true,
                'inv_created_by'  => true,
                'inv_updated_by'  => true,
            ],

            MetaData::MODELS_IDENTITY_COLUMN => 'inv_id',

            MetaData::MODELS_DATA_TYPES_BIND => [
                'inv_id'          => Column::BIND_PARAM_INT,
                'inv_cst_id'      => Column::BIND_PARAM_INT,
                'inv_status_flag' => Column::BIND_PARAM_INT,
                'inv_title'       => Column::BIND_PARAM_INT,
                'inv_total'       => Column::BIND_PARAM_DECIMAL,
                'inv_created_at'  => Column::BIND_PARAM_STR,
                'inv_created_by'  => Column::BIND_PARAM_INT,
                'inv_updated_at'  => Column::BIND_PARAM_STR,
                'inv_updated_by'  => Column::BIND_PARAM_INT,
            ],

            MetaData::MODELS_AUTOMATIC_DEFAULT_INSERT => [
                'inv_created_at' => true,
                'inv_created_by' => true,
                'inv_updated_at' => true,
                'inv_updated_by' => true,
            ],

            MetaData::MODELS_AUTOMATIC_DEFAULT_UPDATE => [
                'inv_created_at' => true,
                'inv_created_by' => true,
                'inv_updated_at' => true,
                'inv_updated_by' => true,
            ],

            MetaData::MODELS_DEFAULT_VALUES => [
                'inv_status_flag' => 0,
            ],

            MetaData::MODELS_EMPTY_STRING_VALUES => [
                'inv_created_at' => true,
                'inv_updated_at' => true,
            ],
        );
    }
}

Custom¶

Phalcon offers the Phalcon\Mvc\Model\MetaData\Strategy\StrategyInterface interface, allowing you to create your own Strategy class.

<?php

namespace MyApp\Components\Strategy;

use Phalcon\Mvc\ModelInterface;
use Phalcon\Di\DiInterface;

class MyStrategy StrategyInterface
{
    public function getColumnMaps(
        ModelInterface $model, 
        DiInterface $container
    ): array;

    public function getMetaData(
        ModelInterface $model, 
        DiInterface $container
    ): array;
}