User Input in Procedures

Introduction

When the values of parameters are determined by the user, an Iis specified in the Input column (or an M, if the input is mandatory). Input does not have to be defined via an INPUT command. You can also specify input in a CHOOSE command, a form step or an SQLI step. In addition, in a processed report, columns can be flagged for input in the report itself (by flagging the Input Column in the Report Columns form).

Inputting a New Value

If, during input, the user is to specify new values (not in the database), you must record a parameter (of any type except ASCII, FILE or LINE), together with a valid width and a title. In such a case, an equal sign (=) will appear in the first line of the column in the parameter input screen.

You can insert a pre-set, revisable value into the input screen — for instance, the current date (SQL.DATE8) for a DATE parameter. The user can then choose between using that value or modifying it. To do so, specify the pre-set value in the Value column (of the Procedure Parameters form) for the parameter in question. Of course, the designated value must match the parameter’s data type. Alternatively, you can specify the name of a variable (e.g., :DATE), provided that its value has already been defined (e.g., in a previous procedure step).

The pre-set input value appears the first time the user runs the procedure. If that value is then revised, the revised value will appear the next time the user runs it. You can, however, ensure that the pre-set value always appears. To do so, enter the Procedure Parameter Extension sub-level form and specify d in the Type column.

If, instead, you want the input to be Boolean (Y/N) and appear as a check box, specify Y in the Type column (of the Procedure Parameter Extension form).

Choosing Between Several Fixed Options

If you want the user to choose between several predefined options within a given input field, create a parameter of INT type, and record the various options in consecutive messages (in the Procedure Messages form). Then enter the Procedure Parameter Extension sub-level form and specify C in the Type column. Indicate the range of message numbers in the From Message and To Message columns.

Notes:

  • To use messages recorded for a different procedure, designate its name in the Entity Name column.
  • The value of this parameter can then be included in subsequent procedure steps (e.g., as the value assigned to a GOTO command).

Choosing Options from a List of Radio Buttons

Alternately, you can create a separate input screen of options, in which the user must flag one of the radio buttons. To do so, use the CHOOSE command. The first parameter of a CHOOSE command stores the result of the user’s choice. Its title appears at the top of the pop-up menu, as its heading. It is this parameter that may be included in subsequent procedure steps.

There are two methods for creating the radio buttons: you can define a list of additional parameters or write a CHOOSE query.

Method 1: When you define a list of parameters, assign each one a unique constant value (an integer), a title and a position. Titles will appear next to the radio buttons in the order dictated by each parameter's position. The value of the option (i.e., parameter) chosen by the user will be assigned to the first parameter.

Method 2: You can write a CHOOSE query in the Step Query sub-level form of the CHOOSE/CHOOSEF procedure step. This is a regular SQL query with three arguments in the SELECT clause. All arguments must be of CHAR type (convert numbers to strings using the ITOA function.

The first two arguments in the CHOOSE query are displayed next to the radio button and the third is the value to be assigned to the parameter. If you want to display a single value as a description next to each radio button, use the empty string (' ') as the second argument.

Example: See the COPYPRICELIST procedure.

Note: Rules for the CHOOSE query are similar to those in CHOOSE-FIELD triggers.

Retrieving Records Into a Linked File

Another type of user input involves retrieval of records from a given database table into a linked file. This case requires specification of Column Name and Table Name. The user can then specify a search pattern in that column, or access a form which displays the records in that table and then retrieve desired records.

Inputting Text Into an HTML Screen

When the procedure parameter type is TEXT, the user keys in an unlimited number of lines in the text field, and these lines are returned to the procedure via a file linked to the PROCTABLETEXT table.

Example:

LINK PROCTABLETEXT TO :$.TXT; 
GOTO 99 WHERE :RETVAL <= 0;
INSERT INTO GENERALLOAD (LINE,RECORDTYPE,TEXT)
SELECT 2+KLINE, 2,TEXT FROM PROCTABLETEXT WHERE KLINE > 0;
UNLINK PROCTABLETEXT;

Other Input Options

Additional columns in the Procedure Parameter Extension sub-level form also affect user input:

  • To allow users to input a file attachment, specify Y in the Browse Button column. A Windows Explorer will open in which the user selects the file in question.

    Note: The parameter in question must be of CHAR type.

  • To allow users to save a new file, specify S in the same column.
  • To encode user input (e.g., when a password is given), flag the Hide User Input column. Anything recorded by the user will appear as a row of ++++++ marks.

Writing a New CHOOSE-FIELD or SEARCH-FIELD Trigger for a Procedure Parameter

When a parameter is defined as an input column, if the column has a target form and that form has CHOOSE-FIELD or SEARCH-FIELD triggers, those triggers will be imported to the input screen.

You can also write a specific CHOOSE-FIELD or SEARCH-FIELD for the procedure. Your trigger can contain references to any input value specified by the user within the same procedure step. For instance, if the procedure step contains an input parameter called CST, its value will be stored in the :PROGPAR.CST variable. This is useful, for example, if a given procedure step contains an input column for a Sales Rep and another input column for a Customer, and you want the Choose list for the latter column to display only those customers that are associated with the specified sales rep.

The same restrictions that apply to form trigger names apply here as well.

To design a new trigger, use the Field Triggers form (a sub-level of Procedure Parameters).

When the parameter is a linked file, the user can specify an exact value for that database column, stipulate a query pattern for that column or access a related target form in which to retrieve records.

In the last case, the user normally arrives at a default target form. This is the form that serves as a “window” into the database table to which the column in question belongs (i.e., the table specified in the Procedure Parametersform), provided that the table and form share the same name. However, there are several ways to override this default, so that the move will be to another root form based on the same table:

  • by designating a main target form (type M in the Zoom/International column of the Form Generator form for the form in question);
  • by designating an application target form (type Z in the same column);
  • by designating a form as a target for this particular parameter (specify the name of the relevant form in the Target Form Name column of the Procedure Parameter Extension form).

The last option overrides all other target forms, and the application target overrides the main target form.

Example: Specify a target form for the parameter when there is more than one form linked to the same base table (e.g., PART and LOGPART).

The specified target form must meet two conditions:

  • It must be a root form (have no upper-level forms of its own)
  • Its base table must include the column from which the user originates.

Note: To disable automatic access from a given column, specify the NULL form as the target form.

Input During Action

When a procedure is activated from within a form, input is received from the record on which the cursor rests. That is, a linked file is created, based on the form’s base table and consisting of that single record. This linked file is input to the procedure by the PAR parameter. Therefore, any procedure that is activated from a form must meet the following conditions:

  1. The PAR parameter must be in the first position of the procedure’s first step.
  2. It must be of FILE type.

If you want to receive additional input from the user, you must create an input screen (using the INPUTF command) or a menu of choices (using the CHOOSEF command).

Tip: To run the same procedure from a menu, make sure that Column Name and Table Name are also recorded.

Using a Form for Input

The content of a linked file may also be input by means of a form (procedure step of type F). This form must be the root of a form tree. It is loaded together with all the sub-level forms in its form tree. A form step is useful when you wish to allow the user to retrieve several records that will serve as input, particularly when the query is complex (entailing several conditions) or when retrieval is not through a key.

Example: See the CLOSEAIVS procedure.

Further Reading