Frames MD3
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Frame Construct MD3

With 'construct' we mean a syntactical form. It can be entered in a table action. In the subject will be a table-variable , in the example KB: first name from frame construct. In one or more action value cells comes the construct. Example:

FRAME(NAME(Person),IDENTIFIER((NAME(ID),VALUE(ID user))),VALUE(first name))

Here all parts are explained.

  1. First keyword NAME identifies the frame whose objects will be accessed.
  2. Keyword IDENTIFIER(( )) stands for the object to access. Between the double parentheses are two parameters around a comma:
    • NAME identifies a frame-variable. This must be the primary key variable as specified in the frame's properties!
    • VALUE holds the name of a table-variable. By user input or reasoning in surrounding tables it is supposed to receive a value that will be searched in the frame objects. It is a primary key value, so it selects one object (or none).
  3. Keyword VALUE at the right of the frame construct again identifies a frame-variable. Its value will be passed to the table-variable in the subject.

This is all with a frame having a simple primary key, being one frame variable. More complicated is a composite primary key. An example is a Dutch address formed by a postcode and a house number. This will be documented later. Meanwhile have attention that above IDENTIFIER has double parentheses. They are mandatory, also in case of a single primary key. In case of a composite key the form is like

IDENTIFIER((first)(second))