Tracker data are stored in tables, each of which contains several fields (or columns), for example, these simplified versions of the Items and Descriptions tables.

item id item # description id
1 1001 2
2 1002 1
3 1003 2

description id description name
1 wrench
2 pickup truck

The Tracker's tables and fields are listed in tables and fields.

The first field in every Tracker table (ITEM ID and DESCRIPTION ID in these examples) contains a value that uniquely identifies its row. Subsequent fields can contain data (like ITEM # or DESCRIPTION NAME) or references to other tables (like DESCRIPTION ID in the items table, which refers to DESCRIPTION ID in the Descriptions table). That reference is a relation.

  • The relation from Items to Descriptions is called 'many-to-one' because many items can have the same description, for example, item #s 1001 and 1003 are both pickup trucks.
  • Going the reverse direction, from Descriptions to Items, the relation is called 'one-to-many' because one description can be referenced by many items.

Relations are used in views, sorts, searches and reports. The Tracker's relations are listed in relations sorted by table 1 then table 2 and relations sorted by table 2 then table 1.