Syntax Highlighting With SQL Developer
Introduction A customer asked me if it is possible show unused identifiers in SQL Developer. Since there is no PL/SQL compile warning for that, you might be tempted to say no. But you can always use PL/SQL Cop for static code analysis. Guideline G-1030 deals…
Book Review: Practical Oracle SQL by Kim Berg Hansen
I work with SQL since decades, and I think to have some practical experience with writing SQL queries on Oracle databases. So why should I buy a book about practical Oracle SQL? If you are in a similar situation like me, read this book review….
Formatting Code With SQL Developer
Introduction I started using SQL Developer in 2013. Back then version 4.0 was the latest and greatest. But the capabilities of the formatter were disappointing. In 2017 Oracle released version 4.2 with a new formatter and has been improving it ever since. Version 19.2 brought…
Design Tips for Query Rewrite
Although Query Rewrite on Materialized Views is a powerful feature which is available in Oracle databases for a long time, it is rarely used. Many developers and database administrators don’t know about it or do not use it because they think it is too complex….
Data Vault Queries and Join Elimination
If you work with Data Vault for a data warehouse running in an Oracle database, I strongly recommend to use Oracle 12.2 or higher. Why that? Since Oracle 12c Release 2, join elimination works for more than one join column. This is essential for queries…
Constants vs. Parameterless Functions
Do you use parameterless PL/SQL functions in your queries? Did you know that this may cause performance issues? In this blog post I explain why parameterless functions can be the reason for bad execution plans in any Oracle Database. I recently had to analyze this…
Integrate SQL*Plus Scripts in SQL Developer
I envy my DBA colleagues when they work with the Oracle Database from the command line in an incredibly efficient way. They just call a series of scripts with some parameters to get the desired information. Everything looks so easy, so smooth, so natural. I’m…
Partition Pruning and NLS Settings
NLS (National Language Support) parameters are very useful for multilingual applications in an Oracle database. But it is important to understand their impact on query performance. I was aware that NLS is important for indexes, but never thought about its impact on partitioning. In a…
Bitmap-based COUNT(DISTINCT) Functions in Oracle 19c
Oracle 19c provides a set of new SQL functions for bitmap operations. They allow fast computation of COUNT(DISTINCT) expressions. What is the purpose of these functions? The Oracle documentation is very sparse, but at least it tells us that the main focus are Materialized Views on…
Materialized View Refresh for Dummies
Materialized Views are often used in data warehouses to improve query performance on aggregated data. But what if it takes too long to refresh the materialized views? Here are some basic rules to improve refresh performance. Unlike indexes, materialized views are not automatically updated with…
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