Key properties and relations

Primary key

A primary key is a property or set of properties that uniquely identifies each instance of its class. Every Integration Composer class must have at least one property defined as a primary key.

In a parent-child relationship, the child class must contain at least one primary key that is also a primary key of the parent class.

For example, the Display class, a child of the Computer class, has two primary keys: Displayid and Nodeid. Nodeid is also a primary key of the parent class, Computer. The combination of Displayid and Nodeid uniquely identifies each instance of the Display class.

Foreign key

A foreign key (FK) is a property or set of properties in a child class that Integration Composer derives from one or more primary key properties in the parent class. When Integration Composer executes a mapping, it copies the value for the foreign key from the primary key of the parent class to the child class.

For example, the Nodeid property in the Display child class is a foreign key to the Computer parent class. When Integration Composer executes a mapping, it copies the value for the Nodeid property in the parent, Computer, to the child, Display.

Alternate key

An alternate key is a property or set of properties that is an equivalent way to identify an instance. The combination of the alternate key values must be unique within the class. If a primary key is a generated value, Integration Composer requires one or more alternate keys.

In the Integration Composer Classes and Properties example, Displaytype, Makemodel, Manufacturer, and Serialnumber are alternate keys for the class Display.

Generated value

A generated value property (GV) is a property whose value Integration Composer generates automatically when you execute a mapping for the target data source. Defining a property as a generated value is meaningful only for target data schemas.

In the Integration Composer Classes and Properties example, the properties Changedate and Createdate are generated values for the class Display.

Reference property

A reference property (Ref) is a property that points to a primary key property in a reference class. When Integration Composer executes a mapping, it copies the value for a reference property from the primary key of the reference class instance.

In the Integration Composer Classes and Properties example, the property Manufacturer in the class Display is a reference to the class Manufacturer.

When you create a mapping, Integration Composer copies the value of the primary key in the class Manufacturer, which is Manufacturervar, to the Manufacturer property in the Display class.

Required properties

In some cases Integration Composer requires a value for a property, meaning that it cannot be null. If a property requires a value, the Integration Composer user interface displays the property with a yellow background in mappings. These properties must contain a value as a result of mapping execution. As such, you must define expressions that do not result in null values for these properties when you create mappings.

The display properties that you set for a computer might affect colors. The color displayed on the computer that you use might vary.

For numeric properties, Integration Composer does not require an expression. For Integers, Integration Composer inserts a default value of zero (0) into the target. For Double and Float, it inserts a default value of 0.0.