Why not use varchar(max)?

Question

I\'m a bit old school when it comes to database design, so I\'m totally for using the correct data sizes in columns. However, when reviewing a database for a friend, I notic

Answer 1

If you are working in an OLTP environment, you are all about the performance. From overhead and tuning concerns to indexing limitations and query bottlenecks. Using a varcahr(max) or any other LOB type will most likely contravene most design best practices, so unless there is a specific business need that cannot be handled through the use of some other typing mechanism and only a varchar(max) will fit the bill then why subject your system and applications to the kind of overhead and performance issues inherent in one of the LOB datatypes?

If on the other hand you are working in an OLAP environment or in a Star Schema DW environment with Dimension tables with descriptors fields that naturally need to be verbose then a varchar(max), as long as you are not adding that to an index, may be useful. Still I would recommend even then to use a char(x) varchar(x) As it is always a best practice to only use those resources you absolutely must have to get the job done.