Here you enter the name of the attribute associated with the fields you have painted on the screen, or you enter expressions such as 'DATE()', for display or entry.

The type of entry you can enter here is related to the prompt type which you have entered and so we will consider each prompt type and the associated possible entries:-

S - Single Value Input

An 'S' type variable refers either to a part of the record key or to an attribute within the main file. Therefore you must enter a variable name which appears on the file layout definition for the main file. The only exception to this is for the key (or components of the key if a composite one) for which any variable name is permitted.

The variable name you use must follow the usual rules for variable names in BASIC programs, e.g. Must begin with an alpha character, must not contain spaces etc,. If the prompt definition refers to an attribute on the main update file, the system will also verify that the attribute has already been defined on the MAIN UPDATE file layout record and that it is defined either as a single valued attribute on this record or specifies a single value in the prompt definition. If either of these validations fail, an error message is displayed.

If the user cannot remember the attribute name or wish to change some aspect of the file layout definition, they should hit the [INVERT] function key. This will take them into the file layout definition screen, normally accessed via option 1 of the main menu. They will then be able to make changes to the file layout definition or use the facilities in the screen to locate the required attribute name.

Note that any changes to the file layouts will be immediately reflected on return to the prompt definition screen. Note that this [INVERT] function is a feature of the field and can be used at any time the cursor is in the ATTRIBUTE/EXPRESSION field.

N - No Input Field

An 'N' type variable is used to display an 'S' type (ie main file attribute) without accepting input. Therefore, the same rules as for 'S' types apply here.

R - Reference only field

An 'R' type variable is used to access a file using an 'S' type (ie main file attribute) without the need to input or display the variable. Therefore, the same rules as for 'S' types apply here. Note again that this variable type has been replaced by the use of the NULL conversion and is only retained for compatibility with previous versions of PARADYME. Its use is no longer recommended.

W - Window

No input of any kind is possible here. The definition of window variables is much the same for single fields but is carried out on another screen. This will be explained in a later section of this chapter.

I - Input to temporary variable.

Here you can enter a variable name of your own design. The variable name cannot incorporate any operators or punctuation marks such as - and +, as this will confuse the compiler, note that '.' is permitted. The variable will be used to hold the value input but is unrelated to the main update file. This type of variable is useful if you intend to use the value for logic inserted into the program (see the topic on 'inserts' below).

The name of the variable holding the input value in the generated PARADYME routine will be the value entered for this field.

V - Variable Value.

For type 'V' you can specify any valid variable or expression for display. This means, for example, that you can display the value of the system function DATE() at this point. In addition you can use expressions which are made up of variables used in the generated PARADYME routine such as 'VALUE$[1,3]', or '10*VALUE$'. At input time, PARADYME uses the variable 'VALUE$' to hold the value input by the user. In addition there are several other variables used by PARADYME programs which can be used in expressions here. These are detailed in the appendix at the end of this manual.

The only difference between an I type variable and a V type is that I types allow input whereas V types ONLY display the data held in the variable. Note that this parallels the difference between S and N types. Note again that S and N types refer to the main update file and I and V types refer to local variables.

All PARADYME variables are distinguished by ending in a '$' sign. Of course, you can also use any other existing variables in your expression, including system variables such as 'DATE()' and your own 'I' type variables or variables set up in logic inserts.

D - Display Value.

Here you can enter the variable name of an attribute which appears on the cross reference file last specified. It must be a field name that appears on the file definition for the selected file as entered via option 1. It must also be a field name that is defined as single valued or that the prompt definition specifies a single value.