What are some of your most useful database standards?

Answer 1

Putting everybody's input together into one list.

Naming Standards

• Schemas are named by functional area (Products, Orders, Shipping)
  
• No Hungarian Notation: No type names in object names (no strFirstName)
  
• Do not use registered keywords for object names
  
• No spaces or any special characters in object names (Alphanumber + Underscore are the only things allowed)
  
• Name objects in a natural way (FirstName instead of NameFirst)
  
• Table name should match Primary Key Name and Description field (SalesType – SalesTypeId, SalesTypeDescription)
  
• Do not prefix with tbl_ or sp_
  
• Name code by object name (CustomerSearch, CustomerGetBalance)
  
• CamelCase database object names
  
• Column names should be singular
  
• Table names may be plural
  
• Give business names to all constraints (MustEnterFirstName)
  

Data Types

• Use same variable type across tables (Zip code – numeric in one table and varchar in another is not a good idea)
  
• Use nNVarChar for customer information (name, address(es)) etc. you never know when you may go multinational
  

In code

• Keywords always in UPPERCASE
  
• Never use implied joins (Comma syntax) - always use explicit INNER JOIN / OUTER JOIN
  
• One JOIN per line
  
• One WHERE clause per line
  
• No loops – replace with set based logic
  
• Use short forms of table names for aliases rather than A, B, C
  
• Avoid triggers unless there is no recourse
  
• Avoid cursors like the plague (read http://www.sqlservercentral.com/articles/T-SQL/66097/)
  

Documentation

• Create database diagrams
  
• Create a data dictionary
  

Normalization and Referential Integrity

• Use single column primary keys as much as possible. Use unique constraints where required.
  
• Referential integrity will be always enforced
  
• Avoid ON DELETE CASCADE
  
• OLTP must be at least 4NF
  
• Evaluate every one-to-many relationship as a potential many-to-many relationship
  
• Non user generated Primary Keys
  
• Build Insert based models instead of update based
  
• PK to FK must be same name (Employee.EmployeeId is the same field as EmployeeSalary.EmployeeId)
  
• Except when there is a double join (Person.PersonId joins to PersonRelation.PersonId_Parent and PersonRelation.PersonId_Child)
  

Maintenance : run periodic scripts to find

• Schema without table
  
• Orphaned records
  
• Tables without primary keys
  
• Tables without indexes
  
• Non-deterministic UDF
  
• Backup, Backup, Backup
  

Be good

• Be Consistent
  
• Fix errors now
  
• Read Joe Celko's SQL Programming Style (ISBN 978-0120887972)