4GL Names
In 4GL, you can specify most of the names and identifiers in statements either statically (when the application is written) or dynamically (at run time). Names that you can specify in both ways are known as 4GL names. The 4GL name is one of the means 4GL provides for substituting values for processing while your application is running.
4GL names include most elements of 4GL syntax that are not reserved words or expressions. Categories of 4GL names include:
• Names of form objects, such as fields and table field columns, in forms statements (such as clear, scroll, resume, and validate)
• Names of database objects, such as tables and table columns, in most contexts within DBMS statements
• Parameter names
• Miscellaneous words in 4GL statements, such as the procedurename in a callproc statement
A 4GL name can be:
Static
• A character string optionally enclosed by quotation marks (the quotation marks are required if the character string is identical to a reserved word)
• An integer.
Dynamic
• Any of the following simple objects (preceded by a colon): a simple field, a simple local variable, a simple global variable, a global constant, or a simple component of a complex object
• A simple variable or constant name, optionally preceded by a colon
For example, in the following example, framevar must be a simple field or variable or global constant of string type:
callframe :framevar
Avoid using a variable of a nullable type as a 4GL name, because a 4GL name cannot contain a null value. If the statement that contains this error executes, the value returned is zero if a number is expected or "$NULL$ERROR" if a character string is expected.
Note: In this guide, 4GL names are underlined in syntax statements.
Last modified date: 08/28/2024