Fence Diagram for Row States and Transitions
The following illustration summarizes the effects of programming statements and user actions on array row states:
• The vertical lines represent the starting and ending row states.
• The arrows are labeled to indicate the statement or action that causes the state to change.
• The numbers in parentheses to the right of each row state indicate the numeric value of the row state constants.
The following statements illustrate a few possibilities:
• If a user opens a new row by selecting the Insert New Row operation of a default control button, the row state changes from nonexistent to RS_UNDEFINED.
– If the user changes the newly inserted row, the row state changes from RS_UNDEFINED to RS_NEW.
– If the 4GL code makes an assignment to the newly inserted row, the row state does not change; therefore the arrow in the fence diagram begins and ends at the same position.
• If a row with a row state of RS_NEW is deleted, its row state becomes nonexistent.
• If a row with a row state of RS_UNCHANGED is deleted, its row state becomes RS_DELETED.
