Introduction I recently had a scenario where a developer after developing an application that had a text box needed to allow that text box to contain attachments and even pictures and thus had to change that text box column from a VARCHAR2 column to a BLOB. However, The column already had data in it. This
Database auditing refers to the monitoring and logging of user activity. It is the most accurate record of any database activity. Auditing helps us keep track of what happened in the database, when it happened and who did it. It also allows us to track the use of privileges, activities of highly privileged users, access
Introduction LATERAL is a join type that allows a subquery to use columns from tables that appear earlier in the FROM clause of the query. It lets us build a mental model of exploring data from the inside out. This feature lets us work with subqueries in a unique way, allowing them to reference columns
What is the High Water Mark (HWM)? The high water mark in oracle refers to a point in a segment beyond which data blocks are unformatted and have never been used. If we imagine a data block as a Rectangular block of data that fills up from left to right, then the high water mark
Introduction As a DBA, data modeling is part of the job; working with developers, reviewing table design, implementing proper constraints and much more. In an earlier post about performance tuning, I talk about some practical steps that can be taken to fix performance problems. However, sometimes those problems could be “self-inflicted” and I ended that
Updated 24th September 2026 A Brief Primer: Constraints Constraints are database objects that help enforce business rules and ensure data integrity. They are typically defined on tables and their columns. They include: I talk a lot more about constraints in a previous post: about database constraints. What are Constraint States? In Oracle, it is possible
It’s patching season once again, and as a good oracle technologists I patch my environments to ensure security, fix bugs and enjoy new features. Additionally, Oracle provides us the autoupgrade utility which helps simplify the patching process. In my earlier post about using autoupgrade for my very first time, I downloaded autoupgrade and used it
Autoupgrade Patching: Cycling Between Oracle Homes Read More »
Introduction For a 30+ year old language, SQL is doing pretty good in terms of its relevance and usefulness. It can solve a lot of problems, even a lot of the problems people believe require a traditional programming language. The legendary Tom Kyte, when asked in an interview about the most underutilized feature of the
Brief Primer: Locks, Blocks and Transactions In an earlier post, I talked about locks and transaction concurrency. A lock is a mechanism used by Oracle to restrict access to a shared resource. Also, in another post, the importance of indexing foreign key columns, I explore how these locks on child tables can lead to blocking.
Introduction Calendar functions, introduced in 23.26.1, provide us with the ability to format dates into standard year/quarter/month/week/day text for these calendars: Each formatted calendar function returns a VARCHAR2 value representing the input date at a particular level of the calendar hierarchy. In this post, I will discuss the Calendar type functions and how to use
Calendar Functions and Date Dims in Oracle Database 26ai Read More »
