Math and SQL Part 6: The Problem with NULLs
This will be the final installment on Math and SQL and will cover the problem with NULLs. NULL handling is probably the most poorly thought-out feature...
View ArticleMath and SQL Part 5: Projection and Selection
The SELECT statement is the workhorse of SQL. Updates and inserts are necessary, but selects are where the power is. One of the significant issues...
View ArticleMath and SQL, Part 4: Basic Data Types - Sets, Tuples, and Bags
A reasonable understanding of the relational model requires understanding the basic data types which make it up, both in the idealized model and in real-world...
View ArticleMath and SQL Part 3: MVCC, Immutability, and Functional Programming
While first normal form is pretty much restricted to relational operations, this piece is more general. It looks at the basic promise of functional...
View ArticleMath and SQL, Part 2: Functions and First Normal Form
There is probably no piece of relational database theory which is so poorly understood in professional literature than first normal form. This piece seeks to...
View ArticleMath and SQL, Part 1: Introduction - Relations and Functions
There are two goals I have in this series. The first is to heavily ground database thinking in mathematics thinking. The second is to connect this...
View ArticlePGObject on CPAN: NoSQL Ideas for PostgreSQL Applications
One of the legitimate points Martin Fowler has argued in favor of NoSQL databases is that expecting application to directly manipulate relational data is far...
View ArticleEncryption: MySQL vs. PostgreSQL
First a note, all my tests involved a relatively simple table with a schema like this (column names did vary):CREATE TABLE enctest ( id int, id_text...
View ArticleIn Defense of Hand-coded SQL
One common comment I get when I point out that I hand-write all of my SQL queries, rather than relying on an ORM or the like, is that it is drudge work,...
View ArticleSetting Up a Cloud in a PostgreSQL-Centric Automation Environment
One of the challenges of setting up a cloud hosting environment is ensuring that systems are as configured and that the desired state is one which can be...
View ArticleArrays and Indexing, Problems and Solutions
Arrays in PostgreSQL are relatively well supported by the indexing engines of this RDBMS. There are a fair number of options however to be aware of and...
View ArticleIntroduction to PostgreSQL Arrays, Basic Concepts and Normalization...
This is part of a two part series. The second will discuss indexing arrays which is a complex topic. PostgreSQL has very good support for arrays of...
View ArticleA Few Cases Where EAV Modelling Really Works in LedgerSMB.
Entity-attribute-value (EAV) modelling is typically seen as an antipattern and for good reasons. Misapplied it leads to inflexible queries, poor...
View ArticleA Distributist View on Software Freedom
We are relatively familiar with Stallman's views on software freedom. These views are deeply based on the idea that we can enumerate rights which...
View ArticleThe LedgerSMB Service Locator for UDF's: How it Works
One of the questions I got from a post last week was how the LedgerSMB service locator works. In the past I have covered the database design side, but...
View ArticleObject-Relational Algebra 3: The Series Join Function
I am back from a break due to working hard on getting LedgerSMB 1.4 closer to release (beta 2 has been released and we are working hard on moving towards...
View ArticleBuilding SOLID Databases: Dependency Inversion and Robust DB Interfaces
Dependency inversion is the idea that interfaces should depend on abstractions not on specifics. According to Wikipedia, the principle...
View ArticleBuilding SOLID Databases: Interface Segregation, or Keep Stored Procedures...
As far as interfaces go, we are talking specifically about functional interfaces (UDF's, or "User Defined Functions", and stored procedures). Raw...
View ArticleBuilding SOLID Databases: Liskov Substitution Weirdness
If the Open/Closed principle starts looking a little strange as applied to object-relational design, the Liskov Substitution Principle applies in...
View ArticleBuilding SOLID Databases: Open/Closed Principle
Like the Single Responsibility Principle, the Open/Closed Principle is pretty easy to apply to object-relational design in PostgreSQL, very much unlike the...
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