Stairway to Columnstore Indexes Level 9: Batch Mode Execution
In this level, Hugo explains what batch mode execution is, how it differs from row mode execution, and what its limitations are.
Stairway to Data, Level 1: The Basics
A great deal of the confusion that occurs when a database application is developed comes from a poor understanding of the basics of data. Here, Joe Celko gives a broad coverage of the difficulties you're likely to meet when handling data in databases.
Stairway to Data, Level 2: Numerics
A confusion about the nature of numbers can lead to a number of problems in database applications. Joe Celko gives a simple guide to the subject
Stairway to Data, Level 3: Strings
Character-handling in SQL is not particularly straightforward, and confusion about collation and character encoding is a common cause of problems with searching, joining, and sorting.
Stairway to Data, Level 5: Types of Scales – Part I
Joe Celko discusses Nominal, Categorical, Absolute, Ordinal and Rank scales. These are the weakest scales we can use, starting with the weakest.
Stairway to Data, Level 6: Types of Scales - Part II
Joe Celko introduces more powerful scales such as Interval, Log interval and ratio scales; before moving on to conversions, punctuation and units. Finally he gives guidelines as to how best to use scales in a database.
Stairway to Data, Level 7: Data Encoding Schemes - Part I
Joe discusses how to deal with the kinds of encoding schemes, how to use them and how to design them. He discusses Enumeration, Measurement, Abbreviation and Algorithmic categories
Stairway to Data, Level 8: Data Encoding Schemes - Part II
Joe discusses Hierarchical, Vector and Concatenation encoding before rounding up with general guidelines for designing encoding schemes.
Stairway to Database Design Level 1: Data Elements
Before you start to think about your database schema or tables, you need to consider your data: the type of data it is, the scale you use for values. It needs to be unique, precise and unambiguous. Then you need to name it in such a way that it can be generally understood. Joe Celko explains...
Stairway to Database Design Level 2: Domains, Constraints and Defaults
A clear understanding of SQL Data Types and domains is a fundamental requirement for the Database Developer, but it is not elementary. If you select the most appropriate data type, it can sidestep a variety of errors. Furthermore, if you then define the data domains as exactly as possible via constraints, you can catch a variety of those problems that would otherwise bedevil the work of the application programmer.
Blogs
Automatic Index Compaction
By ReviewMyDB
Index maintenance has always meant nightly jobs and a window you have to defend....
The Goldilocks problem – Materialized Views
I’m sure you’ve all heard the tale of Goldilocks and the Three Bears, but...
Monday Monitor Tips: Virtual Machine Usage and Cost
By Steve Jones
One of the things I’ve been requesting for a number of years is cost...
Forums
SQL Art, Part 4: Happy 4th of July — A British DBA's Guide to Celebrating a War We Don't Talk About
Comments posted to this topic are about the item SQL Art, Part 4: Happy...
How We Handled a Vendor Retry That Loaded Twice in Snowflake
Comments posted to this topic are about the item How We Handled a Vendor...
Cognitive Coverage
Comments posted to this topic are about the item Cognitive Coverage
Question of the Day
Getting the Average
I have this data in the dbo.Commission table in a SQL Server 2022 database.
salesperson commission Brian 12 Brian 16 Andy 7 Andy 14 Andy 21 Steve 20 Steve NULLAll the data is a varchar, and I decide to run this query to get the totals for each salesperson.
SELECT SalesPerson
, AVG(TRY_PARSE(Commission AS int)) AS TotalCommission
FROM commission
GROUP BY SalesPerson
GO
What average commission is calculated for Steve? See possible answers