The Columns tab displays data dictionary properties for individual columns of the data dictionary's table.
The list on the left displays the set of columns belonging to the data dictionary's table. Selecting a column in this list will display that column's data dictionary properties in the Column Properties grid on the right, where they can be edited.
The Column Properties grid on the right lists the data dictionary property values for the currently selected column.
A short description of the currently selected property is displayed in the panel below the grid control. To obtain detailed information about an property, select it in the grid and press F1 (help).
The properties can be sorted by category (Appearance, Data Dictionary Options, etc.) or alphabetically. The toolbar above the grid control can be used to switch from one ordering to another.
You can change the currently selected column while editing a column property. Press Ctrl+U to select the previous column or Ctrl+D to select the next column.
Long Label is used to assign a label for the column. The Studio will apply the label whenever a form-based control (such as dbForm or dbComboForm) is created in the Visual Designer. The label is only used as a default and can be edited later.
If you leave this blank, then the Studio will use the column name as a label.
Short Label is used to assign a secondary label for the column. The Studio will apply the label whenever a list-type control (such as a dbGrid or dbList) is created in the Visual Designer. The label is only used as a default and can be edited later.
If you leave this blank, then the Studio will use the long label in list-type controls. If the long label is also blank, then the column name is used.
For more information, see Field Appearance.
When the user moves the cursor to a data-entry object for the column, the Status Help is displayed in the status bar. Enter text that will aid the user with data entry to this column.
For more information, see Field Appearance.
Assigns the control type of to the selected column. By default, the Studio will use this information to determine the class of control that is created whenever the column is dragged onto a component from the DDO Explorer into the Visual Designer.
You can enter any class name, but the class must be a member of the Class Palette for the current workspace. Alternatively use the combo list to select one of the standard data-enabled controls. This is more flexible, because the Studio will select an appropriate class for the control type you select, whether you are working on a Windows or Web project. If you type a specific visual class, it will only work for Windows or Web projects, not both. You can configure the class associated with each control type via Configure Workspace Properties dialog – Class Preferences.
Select <none> from the combo list to remove this setting. If you leave this blank, then the Studio will determine for itself, which is the best control to use for the column.
For more information, see Field Appearance.
Mask Type and Mask properties are used in combination to define a data entry mask for the selected column. The mask type determines the syntax of mask characters that can be used in the Mask property.
Use the combo list to select one of the defined mask types. Select <none> from the combo list to remove this setting.
For more information, see Field Appearance.
Mask Type and Mask properties are used in combination to define a data entry mask for the selected column. A central repository of mask strings is available to store mask strings for re-use in other contexts.
Enter a mask string or use the combo list to select a pre-defined mask from the repository. The combo list will display repository masks for the currently selected Mask Type. In addition, the combo list can be used to perform the following mask operations:
<Add to Repository…>: Activates the Add Custom Mask to Repository dialog.
<Edit Repository…>: Activates the Edit Mask Repository dialog.
<Select…>: Activates the Select Mask dialog. This provides an alternative way to select mask strings from the repository.
For more information, see Masks in Windows Applications, Global Mask Repository, and Field Appearance.
Use the combo list to select either True or False. Select True to enable the named Data Entry Option.
For more information about Data Entry Options, see Field Options.
For information about the "Protect Value (key)" option, see Key Fields.
Each column in the data-dictionary may reference a lookup object for a Windows application and a different lookup object for your web application. Lookup objects are usually defined to pop up a list of rows from the table allowing the user to search and select a row that is then loaded into the data-entry view. Since these are user interface elements it is necessary to use different objects in a Windows application than a web application.
In order to reference an external lookup object, you must specify the name of the object. Use the combo list to select a lookup object that is already associated with another column in this data dictionary. In addition, the combo list can be used to perform the following operations:
<Add…>: Activates the Open File dialog. Use this dialog to pick a component file containing a lookup object. This file will be parsed and the lookup object's name will be entered as the property value.
<Remove>: Select this option to remove the lookup object reference.
For more information, see Lookup Lists.
The Validation Type property displays summary information about existing validation properties for the selected column. Validation Type allows you to set up some simple rules for validating data entered into each column. To define these validation properties, click the prompt button. This activates the Column Validation dialog.
For more information, see Field Validations.
Auto-increment columns are automatically assigned a sequentially incrementing number each time a new row is created.
This feature is ideal for having the system automatically assign order numbers to an order header file, or for maintaining unique key column values for any table.
This feature applies mostly to the embedded database. Most SQL databases have IDENTITY columns that perform this action at the backend database level.
In order for the data dictionary to know what next the increment value will be for a new row, it must store the last assigned number in some external table. To specify that a column is an auto-increment column, all you need to do is enter the table name and column name of the external column that will maintain the last assigned number. The format of the table and column reference is:
tableName.columnName
Example
system.order_number
In the above example we are specifying that the order_number column in the system table is used to calculate sequentially incremented order numbers for a column.
Auto incrementing will only work correctly if the external table is a related parent table, or a system table. Click the prompt button to activate the Select Auto Increment Table and Column dialog.
For more information, see Auto-Increment Field.
This setting provides a default value when the user is entering data into the column. Defaults are shown each time the data entry form is cleared in order to create a new record.
You can enter a literal value or an expression into the Default Value form. Expressions must be surrounded by parentheses ().
Examples:
(DefaultDate(self) +10)
This default value is an expression that calls a method called DefaultDate and adds 10 to its return value.
01/01/2009
This is a literal default value that sets a date column to January 1st, 2009.
Special Note: An alternative form of data-entry defaults can be applied by using the column’s Entry Message (see below).
For more information, see Field_Defaults.
Enter the procedure or function name of the data dictionary method that will be triggered on entry/exit navigation or data validation to the selected column. This procedure or function should be defined in the current data dictionary class (or superclass hierarchy).
Use the combo list to select an existing data dictionary class method that has the correct procedure or function declaration prototype for an Entry, Exit or Validation message.
Select <Add…> to activate the Add a New Entry/Exit/Validation Method dialog. This dialog supports creating a new method declaration that is suitable to use as an Entry, Exit or Validation method. The method name is entered as the property value.
Entry and Exit methods are not triggered during navigation within a web application. The asynchronous client-to-server events in a web application mean that entry and exit events have limited value and would be difficult to use.
For more information, see Entry and Exit Methods or Field Validations.
Data Dictionary Validation Objects
Data Dictionary Table Structures