Syllabus Detail

  • Purpose and elements of a data dictionary. 12 ATAR

The purpose of a Data Dictionary

  • A data dictionary is a centralized repository of information for data items used within software (such as databases)
  • A data dictionary can be seen as a database for another database
  • The main purpose of a data dictionary is to provide additional information about the data in a database (such as the data's attributes)
  • Data dictionary's are especially important to developers, as they help maintain an up-to-date reference list items (and their properties) essential to the software
  • In a relational database management system (RDBMS), a data dictionary also contains information on relationships between the given data and other data within a database


Elements of a Data Dictionary

Here are some particular elements that make up a data dictionary. The list below are elements that are known as attributes of a data field in a database. Data dictionary's however have no set limit to how indepth or how long definitions should be; they are fully dependent on the developer(s) of the database.

  • Name = the name of the data item
  • Description = a short description given to the data item to help human's understand its purporse
  • Data Type = read The Computing Teacher's article on Data Types here
  • Field length = refers to the maximum (and / or minimum) length that the value of the data item can be
  • Validation rule = ensures the use of correct and clean data by following the given rule


Further Research

  • Read TechoPedia's definition of a Data Dictionary here
  • Read an indepth artcle on Data Dictionary's by Oracle here


Worksheet and Practice (yet to be added)

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