Edit Key Dialog Box
Allows you to define and edit keys. In XML Schemas, at least one key must be defined in the parent table before a relationship can be created.
To access this dialog box, drag a Key from the XML Schema tab of the Toolbox onto an element or click the New button in the Edit Relation dialog box.
Name
Displays the name for this key.Element
Displays an element that represents the table that contains the key.Fields
Displays the individual elements that are members of the table defined in the Selector box.Allow null values
Determines whether a key can contain a null value.