Query Optimization in PostgreSQL. EXPLAIN Basics – Part 3
I continue a series of articles on the basics of EXPLAIN in PostgreSQL, which is a short review of...
Query Optimization in PostgreSQL. EXPLAIN Basics – Part 2
In my previous article, we started to describe the basics of the EXPLAIN command and analyzed what happens in PostgreSQL when executing a...
Query Optimization in PostgreSQL. EXPLAIN Basics – Part 1
Why does it take so much time to execute a query? Why are there no indexes? Chances are you’ve heard about EXPLAIN in PostgreSQL....
Comparison of Tree Graphs
When developing an information system that also includes various processing of design and...
Understanding Transactions in SQL
A transaction in SQL is a unit of execution that groups one or more tasks together. A transaction is considered successful if all the tasks...
Oracle as Workaround of Mutating Tables
The Oracle mutating trigger error occurs when a trigger references the table that owns the trigger, resulting in the “ORA-04091:...
Oracle Regular Expressions. Dangerous Range
An Oracle developer who often uses regular expressions in code sooner or later can face a...
Don’t like database triggers? You just don’t know how to work with them!
When designing large relational databases, we often make a decision to diverge from a normal form, i.e. denormalization. The reasons for...
Introducing Common Table Expressions in SQL Server
Common Table Expressions, or CTE for short, is simply a technique to create a temporary set of records that can be referenced within an...
Introduction to Temporary Tables in SQL Server
A temporary table in SQL Server, as the name suggests, is a database table that exists temporarily...
