Writing Readable Code

Here are guidelines 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:

  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:

  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 use a style convention for object names consistently. Two typical conventions 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 instance of Microsoft® SQL Server™ is not case sensitive, readability is improved if a consistent style is used. It is 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. This allows for easier readability. For example, use "(price * 1.15) + sales" instead of "price * 1.15 + sales".

See Also

Batches

Functions