There are many good reasons to use ANSI join syntax instead of the old Oracle join syntax. With one exception: If you want to use your Materialized Views for Query Rewrite, avoid to write them with ANSI joins.
Delta detection is a common task in every Data Warehouse. It compares new data from a source system with the last versions in the Data Warehouse to find out whether a new version has to be created. There are several ways to implement this in Oracle.
Our new book “Data Warehouse Blueprints” is now available at Hanser Verlag as printed edition and e-book. Here a short overview of the book and some background information about the long history of this publication.
After creating local and global partial indexes, the last part of this blog post trilogy shows how partial indexes are used by the optimizer for SQL queries – especially for queries in Data Warehouse environments.
Partial Indexes, introduced with Oracle 12c, are available for local and global indexes. In part 2 of this blog post trilogy, let’s focus on global partial indexes on a partitioned table.
Sometimes it would be useful to create indexes for only some of the partitions of a partitioned table. Oracle 12c supports this possibility with Partial Indexes. This blog post shows how local partial indexes can be created – even on an Oracle 11g database.
Data Vault is getting more and more popular for modeling Data Warehouses. Some of my colleagues asked me for book recommendations about this modeling method. Here a short review (from my personal point of view) of two Data Vault standard books.