# Data Dictionary

Data Classes |

Data classes are used to implement standardized definitions for commonly used data elements such as dates, monetary amounts, etc. This means that a data class can be defined according to a standard and then used as a basis for any new data element. The use of data classes simplifies dictionary definitions for similar element types.

Data classes are defined using Data Class Definitions maintenance and stored in a separate file, providex.dcl. When a data class is included for a data element definition (in the Element Description window), information from the data class is loaded into the element definition where it can be adjusted for a particular field if needed. The information that comes from the data class includes the short description, length, default value, validation, print format, user defined tag field, help reference and query information. Most of these fields are used by NOMADS and its sub-systems.

Data classes can be created for many control types (i.e. Multi-Lines, Drop Boxes, List Boxes, Radio Buttons and Check Boxes) for use within NOMADS and its sub-systems, as well as in iNomads. The NOMADS Panel Designer and File Maintenance Generator use this information to generate the desired control type when creating panels. The use of data classes simplifies the creation of controls for similar control types.

When creating panel controls in the NOMADS Panel Designer, data classes can be implemented by using any of the following methods:

- Enter a data Class in the Properties window after a control is drawn. See Multi-Lines, Drop Boxes, List Boxes and Check Boxes.
- Create a control from a data class. See Data Class Controls.
- Create a control from a data dictionary element with an assigned data class. See Data Element Controls.
- Assign a data class in Grid Presets Definition by selecting the Class property.

#### Note:
To apply a data class simultaneously to controls in multiple panels in a single library or in multiple libraries within a specified directory, use the Library Bulk Edit utility.

See Frequently Asked Questions for answers to some commonly asked questions about Data Classes.

Dynamic Control Properties

PxPlus 2018 introduces the capability to create dynamic control properties for Multi-Lines, Drop Boxes, List Boxes and Check Boxes. When combined with data classes, dynamic control properties are ideally suited for data elements with similar properties in an application (i.e. dates, numeric codes, descriptions or lists of values). Dynamic data classes are created by selecting the Dynamic check box in Data Class Definitions maintenance.

For dynamic Multi-Line data classes, Extended Class Validation can be defined (on Validation tab) to provide additional table validation and allow access to data elements for creating display-only Multi-Line controls when designing NOMADS panels.

For dynamic Drop Box and List Box data classes, the Load From File option (on Display tab) allows a data table/file to be defined as the source when populating a drop box or list box at run time. See Populate from Data Source.

See Dynamic Control Properties for information and examples.

#### Note:
Dynamic control properties are supported in NOMADS and iNomads environments.

## Data Class Definitions

Data Class Definitions maintenance is used to create and maintain data classes, including Dynamic data classes, for specific control types. It is invoked by using one of the following methods:

Location | Method
From the PxPlus IDE Main Launcher | Expand the Data Management category and select Data Class Definitions.
From the NOMADS Session Manager | From the menu bar, select Dictionary > Classes.
From Data Dictionary Maintenance | From the Utilities menu, select Data Class Definitions. (The Data Class Definitions option on the Utilities menu was added in PxPlus 2021 Update 1.)
From the PxPlus Command window | From the Utilities menu, select Class Maintenance.

Data Class Definitions maintenance is displayed below with a sample entry:

Depending on the Control Type selected, the properties displayed on each folder tab may vary. The following links provide information on the properties associated with each Control Type:

> Multi-Line Data Class

> Drop Box Data Class

> List Box Data Class

> Radio Buttons Data Class

> Check Box Data Class

## Data Dictionary Elements

If a data class is entered when defining a data element in Data Dictionary Maintenance, the following information from the data class is used in the data dictionary:

Control Type |  | Name of Folder Tab
|  | Display | Attributes | User Aids | Validation | Query
Multi-Line | Description Internal Data Type | Initial Value Input Length Input Format | User Tag Field | Help Reference | Rules | Query Type: Library/Panel, Query Program, Non-Query Logic, Spinner Controls or Calendar (The Calendar Query Type for Multi-Line data classes was added in PxPlus 2025 Update 1.)
Drop Box List Box | Description Internal Data Type Internal Size | N/A | User Tag Field | Help Reference | Default Setting | Query Type: Library/Panel, Query Program or Non-Query Logic
Radio Button | Description Internal Data Type Internal Size | Default Value | User Tag Field | Help Reference | N/A | N/A
Check Box | Description (see Note) Internal Data Type Internal Size | Bitmaps (see Note) | User Tag Field | Help Reference | Default Initial Value | N/A

#### Note:
When a Check Box data class is entered for a data element, the element's Short Description is a combination of the Bitmaps description(s), if applicable, and the Check Box data class Description.

## See Also

Frequently Asked Questions