1. Form Design Aid Guide
  2. Understanding the Relationship between Data Dictionary Items and Controls

Understanding the Relationship between Data Dictionary Items and Controls

On a form, you can use any data item that is in the BV and any data item from the DD. BV items are associated with the database; they are retrieved from and updated to the database tables. DD items are not connected to the database; their values are not retrieved from nor updated to the database tables by the system. On a form, BV items appear with a blue box in the left corner, and DD items appear with a yellow box in the left corner. Use DD items as work fields for ER or fields that are not directly connected to the database table.

You can associate data item values with these control types:

  • Check boxes.

  • Edit controls.

  • Grid controls (columns).

  • Parent child controls (columns).

  • Radio buttons.

    Radio buttons must be associated with DD items. All radio buttons with the same DD item are considered to be a group. Selecting one radio button within the group automatically clears all other radio buttons in the same group.

  • Combo boxes

The rest of the controls types either cannot be associated with a data item, such as push buttons, or essentially act as containers for controls, such as subforms and tab pages, which may in turn be associated with a data item, according to their type.

If you want the user-entered value for a control to update a database record, then the control must be associated with a BV item. For example, a check box can be associated with the database field called Taxable. In the check box properties, the Checked value should be Y and the Unchecked value should be N. You can use these values in ER as well.

Each DD item has a set of properties (such as Default Value) and behaviors (such as Format Rules and Edit Rules). When you create a DD item, you define its default properties and behaviors at that time. You can override previously-defined DD items at the application level, which enables you to further customize how data items behave at runtime. You can disable default properties and behaviors for a specific item, as well as override to use different values and triggers.