5.4. Screen Structure

Many screens are composed of multiple tables.

• A screen can comprise multiple tables stacked from top layer to lower ones on the screen.

• The upper tables on a screen are referred to as parent tables or ancestor tables. The top most table on a screen is referred to as master table.

• Below master are referred to as detail tables or children tables.

• A record in upper table associates with 0, 1, or many records in its immediate lower table by "linking" some fields of the two tables. This association enforces the following effects:

  • Only the upper record exists can the associated lower new ones be inserted.

  • If the upper records scroll, the associated lower ones scroll, too.

  • If an upper record is deleted, the associated lower ones are also deleted.

Refer to screen shots Figure 5-1.