humor

External Article

The Concept of Cardinal Reciprocity- A Primer

  • Article

Too many authors in the field of relational theory have neglected the concept of Cardinal Reciprocity. This can cause a number of subtle problems with database design in terms of its derivability, redundancy, and consistency. . Increasingly, this little-understood aspect of relational theory, that emphasises the cardinality of the attributes of tuples in a relation and the reciprocity with isomorphic foreign key restraints, is becoming a hot forum topic.

2009-04-01

2,846 reads

Blogs

Goodbye, Microsoft

By

A few years ago I took a new job at Microsoft, working as a...

The SUM of Nothing: #SQLNewBlogger

By

I caught this interesting item over on Pinal Dave’s blog: Eleven Interview Questions that...

How to Move the SSMS Status Bar to the Top and Color-Code SQL Server Connections

By

I use color-coded connections in SSMS to distinguish Production, Pre-Production, UAT, and Development. But...

Read the latest Blogs

Forums

Building a SQL Server Fleet Audit That Leadership Actually Reads

By Mayank Sethi

Comments posted to this topic are about the item Building a SQL Server Fleet...

Smart AI Agents and Data Security

By Steve Jones - SSC Editor

Comments posted to this topic are about the item Smart AI Agents and Data...

RegEx Functions IV

By Steve Jones - SSC Editor

Comments posted to this topic are about the item RegEx Functions IV

Visit the forum

Question of the Day

RegEx Functions IV

I have this data in a table in a SQL Server 2025 database: 

EmailAddressID EmailAddress
7              dylan0@ADVENTURE-WORKS.COM
8              Diane1@ADVENTURE-WORKS.COM
If I run this query, which row(s) are returned? 
SELECT top 10
 *
 FROM person.EmailAddress
 WHERE REGEXP_LIKE(EmailAddress, '^D', 'i')
 AND BusinessEntityID IN (7,8)

See possible answers