Oracle Database Security: Database Auditing

In this article, I will continue with Oracle Database Security and I will present some important facts about standard database auditing, audit triggers, and audit policies in Oracle. Database auditing has two components: monitoring and persistent registration of established database activity sets and events. The purposes of database auditing are non-repudiation, investigation of suspicious activities, detection of problems generated by configurations regarding authorization (resources access), compliance with actual legislation and control. Read More

Database Security in Oracle

There is no secret that information makes the world go around currently. If an enterprise takes care of its intellectual property and each employee can easily get the necessary information, the enterprise can hope for the growth. If there is chaos in data, the enterprise will fail despite the team spirit.

In this article, we are going to explore the database security basics and examples of information protection in Oracle. Actually, the theoretical basics for protecting information in the database, which we are going to consider in this article, will be also useful to people working with other databases.

Read More

Example of Improving Query Performance with Indexes

In this article, we’ll look at how an index can improve the query performance.

Introduction 

Indexes in Oracle and other databases are objects that store references to data in other tables. They are used to improve the query performance, most often the SELECT statement.

They aren’t a “silver bullet” – they don’t always solve performance problems with SELECT statements. However, they can certainly help.

Let’s consider this on a particular example.

Read More

50 Shades of Oracle Database Certification Exam

In this article, I would like to talk about one of the basic certifications from Oracle – Oracle Database SQL Certified Expert. Unfortunately, this certification has become unavailable recently, but still, this article may be useful for preparing for other certifications and exams from Oracle. I wish a good read to everyone who wants to know which questions and tricks may await them and wants to be ahead of the game. Read More

Comparison of Tree Graphs

When developing an information system that also includes various processing of design and technological documentation, I faced the following problem.

We have a certain product structure. During the day, different parts of this product are changed and by the evening, it is already unclear what has been changed. Sometimes, products can consist of more than 10 000 elements. The elements are not unique, and the reality is that the structure can be often modified, although the product is almost ready. The failure to understand the scope of changes complicates planning.

The product structure can be represented as a tree graph in PL/SQL. Since I could not find a suitable way to compare two graphs, I decided to create my own method.

Read More

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: table name is mutating, trigger/function may not see it” message.

Let’s have a look at the existing workarounds.

The first one, through the package, is ancient and seems to be effective, however, it takes much time to prepare and run it. The second one is simple and performed using compound triggers.

 

 

 

 

 

 

 

Read More

Oracle Regular Expressions. Dangerous Range

An Oracle developer who often uses regular expressions in code sooner or later can face a phenomenon that is indeed mystical. Long-term searches for the root of the problem can lead to weight loss, appetite and provoke various kinds of psychosomatic disorders – all this can be prevented with the help of the regexp_replace function. It can have up to 6 arguments:

REGEXP_REPLACE (

  1. source_string,
  2. template,
  3. substituting_string,
  4. the start position of the match search with a template (default 1),
  5. a position of occurrence of the template in a source string (by default 0 equals all occurrences),
  6. modifier (so far it is a dark horse)

)

Read More