Phil Factor explores the role of table aliases, explaining when they are required, and their general purpose otherwise, the need for sensible naming of aliases, and how SQL Prompt handles them. Read more
Should you always use EXISTS rather than COUNT when checking for the existence of any correlating rows that match your criteria? Does the former really offer "superior performance and readability". Louis Davidson investigates. Read more
Phil Factor demonstrates the correct use of the RETURN keyword in stored procedures or batches, to pass back a non-zero RETURN code to the calling process, informing it of the error. He also explains some of its misuses. Read more
Phil Factor explains the problems you might encounter when adding a non-nullable column to an existing table or altering a column that contains NULL values to be non-nullable. He demos a migration script that can deploy such changes safely. You might also learn that in an archaic form of the Scots language, used in Cumberland, the number 17 is "tiny bumfit"; I think the tiny bumfit bus goes from Penrith to Carlisle. Read more
Phil Factor demonstrates why SQL Prompt has a 'Best Practice' rule (BP010) that checks for use of the @@IDENTITY function, and suggests less error-prone ways to get the latest identity values used in a table. Read more
Phil Factor illustrates the 'quirks' of the SQL_VARIANT datatype and why it's best to investigate when SQL Prompt alerts you to its use. It is only safe to store data as a SQL_VARIANT, if you explicitly convert it to its true type before you use it. Read more
The SQL Prompt Best Practice rule checks whether a comparison or expression includes a NULL literal ('NULL'), which in SQL Server, rather than result in an error, will simply always produce a NULL result. Phil Factor explains how to avoid this, and other SQL NULL-related calamities. Read more
Louis Davidson demonstrates how SQL Prompt can significantly lessen the pain involved in occasional, 'heavyweight' database refactoring processes, such as renaming modules, tables and columns (Smart Rename), or splitting tables (Split Table). Read more
Many production databases have failed embarrassingly as a result of INSERT code that omits a column list, usually in mysterious ways and often without generating errors. Phil Factor demonstrates the problem, and advocates a 'defense-in-depth' approach to writing SQL, in order to avoid it. Read more
If Prompt warns you of use of the asterisk, or 'star' (*), in SELECT statements, consider replacing it with an explicit column list. It will prevent unnecessary network load and query performance problems, and avoid problems if the column order changes, when inserting into a table. Read more
