What is a data dictionary?

What is a data dictionary? :confused:

MyDictionary["Clock"] = "The time"

Basically a list of items that allows you to use a "key" to access a specific value. The above is a simple example of a dictionary being used as.. well a dictionary, heh :)

When I'm asked to produce a data dictionary it is a document - in WORD for instance - explaining all tables and field elements in those tables and how they relate and what values mean in those tables.

Please be more specific.

Data Dictionary can be used to "translate" meaningless data field names, table names, etc to the end user.
For instance:

in your table you may have fields such

cid
cfn
cln

... and so on.

If you have to build some search utility and you let people to select tables/fields then those names may need to be presented in more "human" language:

Customer ID
Customer First Name
Customer Last Name

Same basicaly goes for table names, views, etc...
I ahve seen databases where tables/fields wree named using some numeric patterns like:

tbl001 / fld001 / fld002

Hope this makes some sense now.

Data Dictionary