Writing Readable Code

Tips for writing readable code:

• Use comments to describe the program or script, including the author, the date, and a description of the modifications.
• Put each major Transact-SQL clause on a separate line so the statements are easier to read, for example:

  USE pubs

  SELECT au_fname, au_lname

  FROM authors

  WHERE state = 'CA'

    

• Put Transact-SQL keywords such as SELECT and FROM, function names such as SUM, AVG, DATEPART, CASE, and CONVERT, and data types such as INT, CHAR, NTEXT in uppercase, for example:

  USE pubs

  CREATE TABLE myauthors

  (

   first VARCHAR(30) NOT NULL,

   last VARCHAR(40) NOT NULL,

   address VARCHAR(40) NOT NULL,

   city VARCHAR(30) NOT NULL,

   state VARCHAR(2) NOT NULL,

   zip CHAR(9) NOT NULL,

   phone VARCHAR(20) NULL

  )

    

• Define and consistently use a style convention for object names. Two common examples are:
  • Capitalize the first letter in each name part; do not separate name parts with underscores: TableName.
  • Make all characters lowercase and separate name parts with underscore characters (_): table_name.

  Even if the current SQL Server installation is not case sensitive, readability is improved if a consistent style is used. It is also good practice to always code object names in Transact-SQL statements using the exact same case as was used to define the object.

• For objects that are common in your organization, define a set of standard abbreviations to be used consistently in object names.
• Use single quotation marks for all character, string, binary, and Unicode constants, so that quoted identifiers are the only items that use double quotation marks (“).
• Use easy-to-type and easy-to-remember alias names when using multitable joins. For example, an alias of t for the titles table and an alias of a for the authors table.
• If the information following a Transact-SQL keyword wraps to another line, consider tabbing the second and successive lines in one tab (usually five spaces) to make it easier to find the major keywords.
• Use parentheses to indicate the execution order of complex mathematical computations. For example, for easier readability, use “(price * 1.15) + sales” instead of just “price * 1.15 + sales”.

See Also