Structures

These are user-defined data types.

There different types of structures:

• Classic

Allows to group different types of data (using elements) under the same name.

An element is either simple (predefined type) or structured (user-defined type).

Other element attributes are:

  * Optional

Indicates whether the value is optional.

• *** Default Value Expression

• An optional expression (null otherwise) used to calculate a default value.

• ** Multiple

• Indicates whether the value is multiple (0 to n elements) or not.

• There different types of elements:

• • Enumeration

• Allows to restrict possible values ​​to a set of named constants (enumeration items).

• • Reference Structure

• Doesn't actually define a data type. Rather, it allows to reference another structure.