SQL

Oracle 20c SQL Macros: a scalar example to join agility and performance

By Franck Pachot . Let’s say you have a PEOPLE table with FIRST_NAME and LAST_NAME and you want, in many places of your application, to display the full name. Usually my name will be displayed as ‘Franck Pachot’ and(…)

SQL Tuning – Mix NULL / NOT NULL Values

One of the difficulty when writing a SQL query (static SQL) is to have in the same Where Clause different conditions handling Null Values and Not Null Values for a predica. Let’s me explain you by an example : Users(…)

A tribute to Natural Join

By Franck Pachot . I know that lot of people are against the ANSI join syntax in Oracle. And this goes beyond the limits when talking about NATURAL JOIN. But I like them and use them quite often. Why(…)

SQL Server 2017: TRIM not only a replacement of RTRIM and LTRIM

Last month, I present in the IT-Tage 2017 in Frankfurt am Main, a session about SQL Server 2017 overview. During my session I made a demo on one of the new string T-SQL Commands:(…)

Documentum – DFC traces setup & investigation

When working with Documentum, you will most probably have to enable the DFC traces one day or another and then work with these traces to analyze them. The purpose of this blog is simply to show how the DFC traces(…)

“_suppress_identifiers_on_dupkey” – the SAP workaround for bad design

By Franck Pachot . In SQL, 'upsert' is a conditional insert or update: if the row is there, you update it, but if it is not there, you insert it. In Oracle, you should use a MERGE statement for that.

APEX Connect 2017 – Day 1

This year again the APEX connect conference spans over three days with mixed topics around APEX, like JavaScript, CSS, SQL and much more. After the welcome speech and the Keynote about “Reconciling APEX and the Thick Database Paradigm” by(…)

How to destroy your performance: PL/SQL vs SQL

Disclaimer: This is in no way a recommendation to avoid PL/SQL. This post just describes a case I faced at a customer with a specific implementation in PL/SQL the customer (and me) believed is the most efficient way of doing(…)

Oracle 12cR2 SQL new feature: LISTAGG overflow

By Franck Pachot . LISTAGG was a great feature introduced in 11g: put rows into line with a simple aggregate function. 12cR2 adds an overflow clause to it. What happens when you have so many rows that the LISTAGG(…)

Oracle serializable is not serializable

By Franck Pachot . Did you know that when you set isolation level to SERIALIZABLE, it is not serializable but SNAPSHOT? This isolation level is lower than serializable. I've never thought about it until I read Markus Winand(…)