What are the advantages of Data Dictionary as applied in computer system analysis and design?

The data
dictionary was created as a programming tool to address the problem of managing large datasets
over long periods of time. For major software projects, such as airline reservation systems,
military C3I applications, or banking systems, which might involve hundreds of programmers,
designers, and support staff, data integrity is a huge issue. Any particular piece of data may
be created, updated, or accessed by multiple users. Especially as software is updated or new
types of application are created, it's important that all stakeholders are making the same
assumptions about what each piece of data contains, what its format is, and who has permission
to update it under which circumstances. By using a data dictionary, designers have a central
point of control and documentation for making changes and updates to data sets and structures.
It also helps programmers working on updating or replacing legacy systems figure out the basic
data structures of the systems they are renovating and the definitions of individual variables.
Also, it allows easy development of new or ad hoc queries using SQL. 

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