Page 218 - DCAP305_PRINCIPLES_OF_SOFTWARE_ENGINEERING

Principles of Software Engineering

Notes • Since most names are constructed by concatenating several words together, use mixed-case
formatting to simplify reading them. In addition, to help distinguish between variables and
routines, use Pascal casing (CalculateInvoiceTotal) for routine names where the first letter
of each word is capitalized. For variable names, use camel casing (documentFormatType)
where the first letter of each word except the first is capitalized.
• Boolean variable names should contain Is which implies Yes/No or True/False values,
such as fileIsFound.
• Avoid using terms such as Flag when naming status variables, which differ from Boolean
variables in that they may have more than two possible values. Instead of documentFlag,
use a more descriptive name such as documentFormatType.
• Even for a short-lived variable that may appear in only a few lines of code, still use a
meaningful name. Use single-letter variable names, such as i, or j, for short-loop indexes
only.
• If using Charles Simonyi’s Hungarian Naming Convention, or some derivative thereof,
develop a list of standard prefixes for the project to help developers consistently name
variables. For more information, see “Hungarian Notation.”

• For variable names, it is sometimes useful to include notation that indicates the scope of
the variable, such as prefixing a g_ for global variables and m_ for module-level variables
in Microsoft Visual Basic.
• Constants should be all uppercase with underscores between words, such as NUM_
DAYS_IN_WEEK. Also, begin groups of enumerated types with a common prefix, such
as FONT_ARIAL and FONT_ROMAN.
Tables
• When naming tables, express the name in the singular form. For example, use Employee
instead of Employees.
• When naming columns of tables, do not repeat the table name; for example, avoid having
a field called EmployeeLastName in a table called Employee.
• Do not incorporate the data type in the name of a column. This will reduce the amount
of work needed should it become necessary to change the data type later.
Microsoft SQL Server
• Do not prefix stored procedures with sp_, because this prefix is reserved for identifying
system-stored procedures.
• In Transact-SQL, do not prefix variables with @@, which should be reserved for truly
global variables such as @@IDENTITY.
Miscellaneous
• Minimize the use of abbreviations. If abbreviations are used, be consistent in their use.
An abbreviation should have only one meaning and likewise, each abbreviated word
should have only one abbreviation. For example, if using min to abbreviate minimum,
do so everywhere and do not later use it to abbreviate minute.
• When naming functions, include a description of the value being returned, such as
GetCurrentWindowName().
• File and folder names, like procedure names, should accurately describe what purpose
they serve.

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