Data Dictionary
Efficiency in Database Design – Part 3
Division 3
Forward: In this part of the series, we look at the meaning of Data Dictionary in a database.
By: Chrysanthus Date Published: 5 Aug 2012
Introduction
Note: If you cannot see the code or if you think anything is missing (broken link, image absent), just contact me at forchatrans@yahoo.com. That is, contact me for the slightest problem you have about what you are reading.
Metadata
The word metadata is means data about data. Data Dictionary or Data Repository is what has the metadata about your tables in a database. Your data dictionary can be in a notebook. It can be a group of files (text editor or word processor files) in your computer. It can also be a database.
Information about Customer’s Database
What should your metadata consist of? It should have:
- The names of the tables and their different column names (table notations).
- Data types of the columns (data domains).
- Primary keys (including composite primary keys) and foreign keys.
- Indexes of columns.
- Relationships between tables (one-to-one and one-to-many).
- Events
The first three points can be kept as a design worksheet that we saw in one of the parts of division one of this series.
There is no really formal way of keeping the data dictionary. However, Computer Aided Software Engineering tools can be used to create, store and search a data dictionary.
That is it for data dictionary. We are towards the end of learning how to design a relational database. The next division will talk how to implement (code) the database you have designed in a Database Management System (DBMS) such as Sybase or MySQL.
We really should take a break now. We continue in the next part of the series.
Chrys
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