Defining Map Fields

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# Defining Map Fields

The fields which are to comprise a map definition can be specified in any of the ways described in this section.

- Defining Fields Directly on the Screen

- Selecting Definitions from Other Objects

- Using System Variables in a Map Definition

## Defining Fields Directly on the Screen

Map fields are defined directly in the map editing area by entering a delimiter character followed by the number of positions to be allocated for the field. The following characters can be used:

Character | Meaning
--- | ---
`9` | Numeric position
`0` | Numeric right justified
`.` | Decimal notation (numeric field only)
`S` | Sign position (numeric field only)
`HH` | Hexadecimal (binary) (must be entered in groups of two)
`X` | Alphanumeric position

A repetition factor can also be specified in the form `(n)`, for example, `X(5)` is equivalent to `XXXXX`.

The following are examples of field definitions (the delimiter character can be changed as required):

`:999` | 3 positions, numeric
`:000` | 3 positions, numeric right justified
`:99.9` | 3 positions numeric with decimal point
`:S9(6)` | 6 positions, signed numeric
`:HHHH` | 4 positions, hexadecimal
`:X` | 1 position, alphanumeric
`:X(7)` | 7 positions, alphanumeric

Fields entered as shown above are assigned a dummy field name by the map editor. Each field must be assigned a name prior to map execution by using either the extended field editing or post assignment function (see the relevant sections). Other field formats can be specified using the extended field editing function.

## Selecting Definitions from Other Objects

You can define a map by selecting definitions from the local data definition of another Natural source object. Data definitions are either field definitions in a DDM or variable definitions.

For a list of objects that can be used to select data definitions, see Object Types and Codes.

#### Restrictions of Selection:

- Programs, subroutines, subprograms, helproutines and functions can only be used if they contain a `DEFINE DATA LOCAL` statement. The definitions of a `DEFINE DATA USING` statement are not available for selection.

- You cannot select fields of the Natural data format U (Unicode), C (Attribute Control) or Handle (object handles). They are not available for selection.

- If you use constants for the bounds of an array and these constants are not defined in the local data definition of the selected Natural source object, the bounds are lost when you select the array.

- You cannot select an item preceded by a period (.), such as a group.

- Input and modifiable (input/output) fields can only be specified once in the map editing area.

This section covers the following topics:

- Listing and Copying Data Definitions

- Checking and Correcting References to DDMs

- Object Types and Codes

### Listing and Copying Data Definitions

To list and copy definitions from other Natural objects

1. Switch on split-screen mode, if required.

2. In the Ob (Object) input fields in the upper left screen section, enter a valid object code (see also Object Types and Codes) followed by an object name, for example, `P TEST` as shown in the example in Step 4. If required, delete any remaining characters in this line.

   Or:
   Leave the first input field (denoted by an underscore) of the upper left Ob input fields blank and enter a question mark (?) in the second input field or press PF1 (Help). If required, delete any remaining characters in this line.

   When you press ENTER, the Select an Object screen appears with a list of all objects contained in the current library. You can press ENTER to scroll don the list. In the Select field, enter the number that corresponds to the object you want to select.

3. Press ENTER.

   The data definitions in the `DEFINE DATA` section of the Natural program (in the following example, program TEST) are displayed in the upper left section of the map editing screen.

   To scroll in the list of data definitions, in the Ob input fields, overwrite the existing entries (in the following example, `P TEST`) with any of the following positioning commands and leave the remaining characters:

   Command | Explanation
   --- | ---
   `+` | Scrolls down one page in the list.
   `++` | Scrolls to the end of the list.
   `-` | Scrolls up one page in the list.
   `–` | Scrolls to the beginning of the list.
   `+n` | Scrolls down n lines.
   `-n` | Scrolls up n lines.

4. To display the data definitions of another object, in the Ob input fields in the upper right screen section, enter a valid object code (see Object Types and Codes) followed by an object name and delete any remaining characters in this line.

   For example:

       Ob P TEST                               Ob L LDA01
       1 #NAME-START               A20         A #NAME-START              A20
       2 #NAME-END                 A20         B #NAME-END                A20
       3 #MARK                     A1          C #PERS-ID                 A8
       . EMPLOYEES-VIEW            *V1         D #MAKE                    A20
       4 PERSONNEL-ID              A8          E #MODEL                   A20
       5 NAME                      A20         .
       001   --010---+----+----+---030---+----+----+---050---+----+----+---070---+----

   Or:
   Select an object from a list as described earlier in Step 2.

5. Copy data definitions into the map editing area:

   - In the map editing area, in any position of a blank line, enter a delimiter character followed by the sequential number or letter displayed next to the data definition required. For example:

         (3

     Selects the data definition assigned to the number 3 (in the example above, `#MARK`).

         :C

     Selects the data definition assigned to the letter C (in the example above, `#PERS-ID`).

   - Press ENTER.

     The characteristics of the data definitions (name, format, length or array definitions) are copied into the map.

     You can display or modify the copied values by using the map editor's field editing functions described in the sections Extended Field Editing and Array and Table Definitions.

### Checking and Correcting References to DDMs

For each map field copied from a DDM, an `INCDIR` statement is automatically generated into the map source. The `INCDIR` statement contains the name of the DDM file and field referenced by the map field. You can check whether an `INCDIR` statement contains an invalid DDM reference by switching on the `CHKRULE` option of the `COMPOPT` system command. Natural then issues an appropriate error message when you catalog the map definition. For detailed information, see CHKRULE - Validate INCDIR Statements in Maps in the System Commands documentation.

From the map editing area, you can list all `INCDIR` statements and change the name of a DDM if required.

To list and update single or multiple `INCDIR` statements

1. In any line of the editing area, enter the following line command:

       ..L

   A Modify INCDIR Statements of Map screen similar to the example below appears with a list of all `INCDIR` statements generated into the source of the current map definition:

        16:24:23        - Modify INCDIR Statements of Map  MAPTEST  -       2008-05-14
                                                                          Top of List

              DDM Name                          Field Name
              AUTOMOBILES                       MAKE
              AUTOMOBILES                       OWNER-PERSONNEL-NUMBER
              FINANCE                           BANK
              AUTOMOBILES                       MODEL
              EMPLOYEES                         PERSONNEL-ID
              AUTOMOBILES                       BODY-TYPE
              EMPLOYEES                         FIRST-NAME
              AUTOMOBILES                       NUMBER-OF-CYLINDERS
              EMPLOYEES                         MIDDLE-I
              AUTOMOBILES                       HORSEPOWER
              EMPLOYEES                         NAME
              AUTOMOBILES                       PISTON-DISPLACEMENT
              EMPLOYEES                         MIDDLE-NAME
              AUTOMOBILES                       WEIGHT
              EMPLOYEES                         MAR-STAT
              AUTOMOBILES                       COLOR

       Enter-PF1---PF2---PF3---PF4---PF5---PF6---PF7---PF8---PF9---PF10--PF11--PF12---
             Help        Exit        GenC  --    -     +     ++

   The list contains the names of all DDM files and DDM fields from which you copied a map field.

2. If required, change the DDM name for a `INCDIR` statement by replacing the name(s) in the DDM Name column.

   Or:
   Press PF5 to open the Generic Change window. In the New DDM Name field, enter the name of the new DDM to be used by all `INCDIR` statements that reference this DDM.

   The DDM name(s) in the corresponding `INCDIR` statement(s) are updated when you save the map definition by using either the Save Map or Stow Map function.

### Object Types and Codes

Listed below are the object types and the corresponding object-type codes that can be used to select data definitions:

Object Type | Type Code
--- | ---
Parameter Data Area | `A`
Predict Conceptual Files (only if Predict is installed) | `C`
Global Data Area | `G`
Helproutine | `H`
Local Data Area | `L`
Map | `M`
Subprogram | `N`
General Object | `O`
Program | `P`
Subroutine | `S`
View (DDM) | `V`
Function | `7`

Note
Object type `O` (General Object) is offered as a convenience option, allowing the user to import data from a source without specifying the correct object type. This is useful, if the user can specify an object name, but can not specify the object type. It is then possible to enter `O objectname` in the OB field of the map editor (where `objectname` represents the object name). The editor then automatically changes the object type from `O` to the correct type and imports the data.

## Using System Variables in a Map Definition

Natural system variables can also be specified in a map definition. For information about system variables, see System Variables and System Functions in the Programming Guide and the detailed variable descriptions in the System Variables documentation.

A system variable must be preceded by an output delimiter as indicated in the following examples:

    (*TIME
    (*DATE
    (*APPLIC-ID

### On this page

- Defining Fields Directly on the Screen
- Selecting Definitions from Other Objects
- Using System Variables in a Map Definition