If models are new to you, this is for you.

You probably understand this intuitively. Each Person has a name (top right) . Each skill has a name (top middle). People have skills, so Person is linked to Skill via PersonSkill (in the middle)

Jobs have names (top left). Each job needs specified skills so is linked to skills (ReqJobSkill).

If it is planned for a person to occupy a particular job, this needs to be recorded (JobOccupancy at the bottom). Note that the StartDate for this person on this job could be 3 years into the future.

If a record of all available courses is kept (Course - top right), it could be useful to also record the skills taught by each course (SkillTaught - middle).

The comments on the model describe one way to use the information depicted in the model.

Note that although you may have 100 staff members in your organisation, only one Person is shown. This is because the model shows the STRUCTURE of the business information, not the actual information. The blocks Person, Job, and so on, are called entities. The actual information will be stored in tables, one table per entity on the model.

This example only shows entities for a human resources situation, but you can imagine that for any business situation there is an equivalent model. For the sales part of the business you would have entities such as Customer, Product, SalesOrder, and for the production part of the business typical entities would be Factory, Machine, Batch, and so on.

You noticed that the model does not show the actual data, but rather the structure of the data. i.e it shows data about data. This is often called MetaData.

It should be apparent from this small example that MetaData is at the heart of 21st century systems, both computerised and manual.