database.orm.mixin.Mappable Class

Namespace: database.orm.mixin

Provide attributes for defining how subclasses map to relational database tables

Since R2023b

Description

database.orm.mixin.Mappable is an abstract class that provides attributes for defining how subclasses are mapped to relational database tables. Methods such as ormread, ormwrite, and ormupdate use these attributes to read and write objects directly to and from databases.

Class Attributes

Abstract	true
HandleCompatible	true

For information on class attributes, see Class Attributes.

Methods

Public Methods

rowfilter

Return an unconstrained rowfilter object for filtering by the objects' properties

More About

Mappable Class Attributes

These class attributes are specific to Mappable subclasses.

TableName	Defines the name of the corresponding table on the database.
Catalog	Defines the catalog where the corresponding table resides.
Schema	Defines the schema where the corresponding table resides.

Standard attributes also apply to Mappable subclasses. For details, see Class Attributes.

Mappable Property Attributes

These property attributes are specific to Mappable subclasses.

ExcludeFromDatabase	If true, identifies a property that should not be saved as a database column.
PrimaryKey	If true, the associated column is a part of the table's primary key. Requires ExcludeFromDatabase to be false. At least one property must have the PrimaryKey property.
ColumnName	Defines the name of the associated column on the database table.
ColumnType	Defines the type of the associated column on the database table.
AutoIncrement (since R2024a)	If true and if the data type is integer: The database automatically creates values for the PrimaryKey property when you insert the property with the ormwrite method. Requires PrimaryKey to be true. The ormwrite method creates a table definition with an autoincrementing primary key column. Supported databases include: PostgreSQL MySQL® MariaDB® SQLite Microsoft® SQL Server® Microsoft Access® Oracle®
ForeignKey (since R2024b)	If true, indicates that the property represents a foreign key relationship between the referencing class and the referenced class. Limitations include: The property must be a subclass of database.orm.mixin.Mappable. The value of the property must be scalar.
LinkTables (since R2024b)	If true, the property represents a link table on the database enforcing a many-to-many relationship between two classes. Limitations include: The property class must be a subclass of database.orm.mixin.Mappable. Values of the property can be vectors, scalars, or empty.

Standard attributes also apply to Mappable subclasses. For details, see Property Attributes.

Version History

Introduced in R2023b

R2024b: Support ORM class mappings with Mappable attributes

You can now use link tables or foreign keys to specify relationships between ORM classes.

R2024a: Insert ORM objects with autoincrementing primary keys

You can now use autoincrementing primary keys by setting the Autoincrement property attribute.