1. SQL Server May Let You Do It, But it Doesn’t Mean You Should
Samantha Fahrmann
Caliber Public Safety

2. About Me Application Developer – 7 years @slfahrmann on Twitter
Working with SQL in a development role for 7 years
Working with SQL in an Accidental DBA role for 4 years
First Time Presenter

3. Agenda T-SQL Bad Habits Management Studio Bad Habits
Database layout and design
Maintenance, Configuration and Defaults
The “I can’t believe you just did that” list

4. T-SQL Bad Habits Select * Cursors Where IntField = ‘1’
Coding in SQL – code reuse
Functions in views
Inline select
Select * because It’s easy – I don’t know what I want. Just starting out – not looking forward.
Cursors – there’s a time and place for it. But usually a better option – Search collection.
Scalar value functions in column definitions in views – script Demo
Inline select script demo

5. Management Studio Bad Habits
Edit top 200 for small one field change
Select top 1000 for 1 record
Select top 1000 for getting what the table looks like – “What’s my column name?”
Developers coming from Access – Go to
Accidental Data modification – multi-tasking
Do you really need to select all that data to make a change in one or two columns for a record?
Select top 1000 – cause I’m not quite sure what record I need or the identity column to sort or filter on.

6. Database Layout and Design
Column Based Settings Tables
Not looking forward
Data type abuse
Normalization or lack there of…
Indexing
UniqueIdentifier as PK and Clustered Index
Add a setting to application – add a column
Did you consider design, how the data will change over time, what could be added later.
Don’t know exactly what they want – default nvarchar(50), nvarchar(200), ntext – do you even need Unicode?
SQL does have a max width for a table row – remember that. Violation
SQL server does have max on column count and index count per table. Doesn’t mean you should ever get there.
Developers adding indexes without understanding – Bit field indexes – Index on a single column every time one is added.

7. Maintenance, Configuration and Defaults
Optimize For Ad-Hoc Workloads (Good Habit)
Max Server Memory
Database Creation
Initial Size
Growth Rate
Auto Shrink
Location on Disk
TempDB
Backups and Recovery Model
Built in setting in configurations- Ad-Hoc not many reasons why not to use this –
Database creation – using defaults- will not play nice down the road. Rubber band log files.
You only have a C:\ Drive? Are you sure you know what you are doing? Sometimes I wonder about people.
Backups – not having one – setting them and never checking them – where are they going?
Database set to Full – we’ll just shrink regularly to maintain (Say What?!)
Database set to Full – Single transaction log backup at same time every day with full backup – someone please explain the benefit of this to me?
Log File growing out of control – we can fix this – just set it to simple right? That fixes everything! NO NO NO

8. I Can’t Believe You Just Did That!
Shrink Database – “OH NO, there’s a little free space in there”
NTEXT – “We’re just not sure what data will go there yet”
Server uptime – 200+ days – “Are you sure you know what you’re doing?”

9. Questions?