The models describe parts of simple databases for:
| Sports Clubs and Events | CD/Video/Tape Library |
| Route Mapping | Motorcycle Servicing and Sales |
| Tool Hire | Wine-to-Course Allocation |
| Files-on-Disk | Research Articles |
| Sports Clubs and
Events
The first LDS describes the situation: A person may attend a number of training sessions. A training session is attended by zero or more persons. |
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The next LDS describes a database which stores information about a number
of clubs.
People may be members of more than one club
(and naturally a club usually has more than one member.)
The people have skills which are used in or
related to their membership of a club (or clubs).
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In the databases described by the following 2 LDS's, a player's performance in matches is recorded, from slightly different perspectives.
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| This LDS describes the situation:
Club members attend events. Members each have one particular ability (which is used in the event). Each member has a rank (It can justifiably be argued that 'Rank' and 'Position' should be entities in the same way, and for the same reason, that Ability is an entity.) |
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| CD/Video/Tape Library
An attempt at a general model for a CD/video/tape library. A star/artist appears in/on a number of films/cds/tapes. If this describes a tape/cd library, could the 'Link' entity become 'Track'? |
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A 'Recording' Database
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Route Mapping
The next LDS describes a database to store information about routes
used for training and testing advanced motorcyclists.
A route is made up of a number of sections.
Each section is a stretch of road, which has a 'difficulty' rating. A stretch
of road has a start and end points which are named locations. A road section
may be used in a number of routes.
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Motorcycle Servicing and Sales
A database to track motorbike maintenance.
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And a database to track changes in second-hand
motorbike prices:
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Tool Hire
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Wine-to-Course Allocation
What wine would you like with this course, sir, madam?
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Files-on-Disk
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Research Articles
A database to keep track of articles found
in different magazines and journals.
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Copyright Tony Drewry - last edit April 2003