In the third part of the PTF-series we learn how a PTF can change the cardinality of the input data flow: return more or less rows as in the input. We’ll use the same simple table as in the part 2 and our new task will be column transposing. We’ll still define, which columns have to stay unchanged (as we already did using the parameter cols2stay). All other columns should be displayed as key-value pairs. Continue reading

# Online Statistics Gathering for ETL – Part 3

Preparing my session on Online Statistics Gathering for ETL for the DOAG conference, I noticed some points that I didn’t covered in the previous two blog posts. The first point is showing the problem that may arise if indexes are involved. The second one is about partition exchange load and it completes the topic of partitioned tables started in part 2. No blog posting on Oracle products is nowadays complete without mentioning the cloud. The third point is about Autonomous Data Warehouse Cloud Service and Online Statistics Gathering improvements. Continue reading

# Polymorphic Table Functions (PTF) , Part 2 – More Basics With Some Deep-Dive

In the first part of PTF series we went through a very basic example removing some columns and adding a new column with a constant value. Starting from the same example we’ll do something more meaningful in the second part. How about concatenating the values of the removed columns as CSV in a new column? Continue reading

# Polymorphic Table Functions (PTF) – Tinkering with Rowsets

Writing the second “basics” post on PTF I discovered, that there were much more details worth mentioning, than it would be acceptable for a “basics” post and would blow it up anyway 😉 So I decided to to separate the tests and finding in this (more deep-dive) post. Continue reading

# Polymorphic Table Functions (PTF) , Part 1 – Basics

I have already posted some examples on Polymorphic Table Functions in Oracle 18c in the last months. I quickly realized how difficult it is to explain completely new feature using advanced examples and wanted to write a series of posts starting from very basics. Now that the Germany’s Oracle User Group (DOAG) has accepted my presentation on PTF for their annual conference is the time to do it. Continue reading

# Online Statistics Gathering for ETL – Part 2

In the first part we looked at general preconditions for online statistics gathering to work and some restrictions. In this part we’ll take a look at what happens with direct path loads into partitioned tables. Continue reading

# Online Statistics Gathering for ETL – Part 1

Online Statistics Gathering has been introduced in 12c and is a very handy feature for ETL and batch jobs developers. However the devil is in the detail. There are some points to remember. Let’s take a closer look. Continue reading

# Conditional Logic in SQL

A few days ago Sven Weller has published an excellent post about writing conditional logic in SQL and it reminded me of an example I used in one of my presentations. It is also about conditional logic in SQL but maybe some less obvious use cases in context of function calls and sorting. Continue reading

# Polymorphic Table Functions Example – (NOT) Transposing Rows to Columns

It was not possible for me to write a follow-up to my last post about Transposing Columns To Rows with PTF showing an opposite task of transposing rows to columns right next weekend as I thought. Partly because of our awesome Trivadis TechEvent which took place back then and partly because this kind of the exercise turned out to be much more difficult one as supposed. Actually it is a nice example to see the limitations of the new feature. Continue reading

# Polymorphic Table Functions Example – Transposing Columns To Rows

Hey, Oracle 18c is now available on the cloud and for engineered systems! For more than a week now. That also means you can play with it at LiveSQL. And of course you can try polymorphic table functions (PTF)! At least I’ve done that this weekend 😉 And here is my first working example. Continue reading