Setting up a dimension table. The dimension table data is used as a reference to
the fact table data. If necessary, complex descriptions can be divided into
several small parts, for example readers’ information at a certain time. During
the initial set-up stage, it is essential to assure that the dimension table’s
primary key will not be changed in any way. If the primary key changes, the
fact table will also change. The dimension table is set up through a process of
denormalization.