On datatypes ¶

tl;dr While you're unlikely to lose data, you might not get the same datatype back that you put in. Use your understanding of the attribute in the context of your app to decide how to handle it after loading a model. When you want to use an attribute in a query, you have to specify its datatype.

Types are a bit of a muddle between DynamicActiveRecord, Maria Dyanic Columns and JSON and you may need to take some care. For all DBMSs except Maria, dynamic attribute are (will be) serialized and unserialized PHP's json_encode() and json_decode(). The same datatype conversion considerations and corner cases apply as in any use of JSON serialization, e.g. JSON has no integers, JSON arrays are different from PHP's, etc.

In Maria the situation is worse. Data is saved via SQL and retrieved via JSON. This may seem perverse but here's the logic.

To save dynamic attribute in a Maria dynamic column, we have to use use the COLUMN_CREATE('name', value) SQL function. Maria infers an SQL datatype from the value and saves it with the dynamic column.
When we load a record from the table into a model, we want the datatypes and values. We cannot retrieve the datatypes using Maria's COLUMN_GET() function so we instead use Maria's COLUMN_JSON() getter to fetch all the record's dynamic columns at once together with data converted into JSON's types.

This is better than nothing and should be tolerable in a lot of cases but it is a bit weird and introduces a number of considerations regarding datatypes through the life-cycle of an AR model/record.

So the data life-cycle with Maria is, roughly

String values that JSON cannot represent are encoded as base64 data URIs.
The Dynamic AR model with PHP types is converted to an SQL command string on save
Maria infers SQL types from the values in the SQL command an saves them with the data
On load, Dynamic AR requests the saved dynamic columns in JSON format from Maria
(A but in Maria's JSON encoder is worked around)
Dynamic AR converts the JSON to PHP
Data URI values are decoded.

Null ¶

Maria does not save a dynamic column with a null value, thus

SELECT COLUMN_CREATE('a', 1, 'b', null) = COLUMN_CREATE('a', 1);
>> 1

So $product->foo = null; $product->save(); actually deletes dynamic attribute 'foo' in the corresponding DB record (assuming that record had a 'foo' before the save).

This is perfectly reasonable. The meaning and purpose of SQL NULL makes no sense for dynamic fields. The correct way to represent something as not existing in dynamic columns is for it to not exist. It isn't so straightforward in a normal SQL table column, which is why it can have the NULL type/value.

So, even though JSON can adequately represent a PHP null, DynamicActiveRecord does not (actually could not) distinguish dynamic attributes with null values from nonexistent ones over the save/load cycle.

So consider setting a dynamic attribute to PHP null as being the same as unsetting it. And when you read an attribute that doesn't exist, DynamicActiveRecord returns PHP null, unlike ActiveRecord which throws an exception.

Boolean ¶

SQL doesn't have bools but JSON does. Maria (SQL) converts to INT 0 or 1 on save so you should get integer 0 or 1 after loading from the DB.

Number types ¶

SQL doesn't have float but has integer and decimal. JSON has only number, which is a decimal and usually converted from and to an IEEE floating point double without NaN on each end of the serialization. PHP has integer and IEEE floats. This can get tricky but these are old problems that have little to do with Dynamic AR.

Array ¶

DynamicActiveRecord saves PHP arrays such that they are associative on load. In other words, you may as well use string keys because they will be strings on load and they need to be strings when dynamic attribute names are used in queries.

Empty arrays are not saved in Maria.

Object ¶

DynamicActiveRecord casts objects to PHP array before save so may as well use arrays instead of objects.

Class Reference

Class	Description
spinitron\dynamicAr\DynamicActiveQuery	DynamicActiveQuery represents queries on relational data with structured dynamic attributes.
spinitron\dynamicAr\DynamicActiveRecord	DynamicActiveRecord represents relational data with structured dynamic attributes in addition to column attributes supported by ActiveRecord.
spinitron\dynamicAr\ValueExpression	A ValueExpression object represents the value of a dynamic attribute that DynamicActiveRecord uses directly (unescaped) in SQL instead of using PDOStatement::bindValue.
yii\base\Arrayable	Arrayable is the interface that should be implemented by classes who want to support customizable representation of their instances.
yii\base\ArrayableTrait	ArrayableTrait provides a common implementation of the yii\base\Arrayable interface.
yii\base\Component	Component is the base class that implements the property, event and behavior features.
yii\base\Configurable	Configurable is the interface that should be implemented by classes who support configuring its properties through the last parameter to its constructor.
yii\base\Model	Model is the base class for data models.
yii\base\Object	Object is the base class that implements the property feature.
yii\db\ActiveQuery	ActiveQuery represents a DB query associated with an Active Record class.
yii\db\ActiveQueryInterface	ActiveQueryInterface defines the common interface to be implemented by active record query classes.
yii\db\ActiveQueryTrait	ActiveQueryTrait implements the common methods and properties for active record query classes.
yii\db\ActiveRecord	ActiveRecord is the base class for classes representing relational data in terms of objects.
yii\db\ActiveRecordInterface	ActiveRecordInterface
yii\db\ActiveRelationTrait	ActiveRelationTrait implements the common methods and properties for active record relational queries.
yii\db\BaseActiveRecord	ActiveRecord is the base class for classes representing relational data in terms of objects.
yii\db\Query	Query represents a SELECT SQL statement in a way that is independent of DBMS.
yii\db\QueryInterface	The QueryInterface defines the minimum set of methods to be implemented by a database query.
yii\db\QueryTrait	The BaseQuery trait represents the minimum method set of a database Query.