Week 4 - Simple version of Metadata

As stated in the articles and books for this week, Metadata is information about information. Here is a simpler explanation.

Think of unsorted laundry. You put whites in one pile and colors in another. Meta data would tell the data base manager/application to create a chest of draws and put baskets inside. As items are entered the Meta data identifies the type: "This is a white sock, place it and all other socks in chest-draw #1. This is a blue T-shirt, place it and all other T-shirts in chest-draw #2 (where chest-draws =storage tables). Meta data also tells the data base that 999 baskets will fit in each chest-draw (where one basket= one data entry record), that there can be seven or more draws available and that each has whatever number of filled baskets, etc. When the chest-draw is full one must create/open another draw.
One must also note that unsorted Laundry cannot be dumped into draws labeled for sorted items. Only like- types are allowed. While you can put blue, green and white T-shirts in the same draw, they still have to be T-shirts. One can not place a white sock in with a white T-shirt. Likewise, one cannot place more than one sock or T-shirt in each basket. Meta data also says to name each basket something unique. Most databases have what they call a primary key. This key is usually a number (SSN, Acc, Order#, ect) that is used to quickly access the draw where the basket holding the T-shirt or sock that you need is stored. That way one need not rummage through every draw and basket looking for the Hello-Kitty socks or the Born-to-Bust-A-Move T-shirt.
To conclude, Meta data is the instructions that tell the storage, processing and retrieval functions how to behave. I hope this helps.