DEFINE

Syntax

[PUBLIC|PRIVATE] DEFINE variable-definition [,...]

where variable-definition is:

identifier [,...]
   {
     datatype
   |
     LIKE [dbname:]tabname.colname
   }
   [ ATTRIBUTES( attribute [ = "value" ] [,...] ) ]

1. identifier is the name of the variable to be defined.
2. datatype can be a data type, a record definition, an array definition, a user defined type, a built-in class, an imported package class, or a Java™ class.
3. dbname identifies a specific database schema file.
4. tabname.colname can be any column reference defined in the database schema file.
5. attribute is an attribute to extend the variable definition with properties.
6. value is the value for the variable attribute, it is optional for boolean attributes.

Usage

A variable is a named location in memory that can store a single value, or an ordered set of values. Variables can be global to the program, module-specific, or local to a function.

You cannot reference any program variable before it has been declared by the DEFINE statement.

By default, module-specific variables are private; They cannot be used by an other module of the program. In order to improve code re-usability by data encapsulation, we recommend you to keep module variables private, except if you want to share large data (like arrays) between modules. To make a module variable public, add the PUBLIC keyword before DEFINE. When a module variable is declared as public, it can be referenced by another module by using the IMPORT instruction.

When defining variables with the LIKE clause, the data types are taken from the database schema file at compile time. Make sure that the schema file of the database schema during development corresponds to the database schema of the production database; otherwise the variables defined in the compiled version of your modules will not match the table structures of the production database.

To write well-structured programs, avoid global variables. If you need persistent data storage during a program's execution, use variables local to the module and give access to them with functions, or make the module variables PUBLIC to other modules.

Variables can be defined with the ATTRIBUTES() clause, to specify meta-data information for the variable. This feature is especially used when defining variables for XML-based Web Services. For more details about XML attributes, see Attributes to customize XML serialization.