David Njoku

David Njoku is a software developer at CACI. His tools of choice are Oracle technologies and he has over a decade of experience building applications with Oracle Forms, Oracle Application Development Framework and Oracle Application Express. David holds a degree in Accountancy and earned his bread as a short story writer and a magazine editor and columnist before turning to IT. David can be contacted at about.me/davidnjoku.

01 March 2017
01 March 2017

Oracle for Absolute Beginners: Users, Synonyms, Privileges, & Roles

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I accidentally locked myself out of my house this evening, and so I had to climb up the wall like a burglar and clamber in through a bathroom window, while the neighbourhood kids all watched and giggled, probably taking secret photos to share on Snapchat or something.  Embarrassing, yes, but what’s it got to do with Oracle? Well, the point… Read more
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22 February 2017
22 February 2017

JSON For Absolute Beginners: Part 6 – Generating JSON post-12c Release 2

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In this sixth and final installment in this introductory series on JSON I’d like to revisit the question of generating JSON from your Oracle database. Cos it’s great to be able to consume a format; but if you can’t spit it out easily too you’ll probably want to look elsewhere. Easily, that’s the keyword in that sentence. In my previous… Read more
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15 February 2017
15 February 2017

Oracle for Absolute Beginners: Data Types

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All databases stand on a tripod of datatypes: strings, numbers and dates. And so I’d imagine that by Day 2 or so of dabbling with Oracle you’d be starting to get reasonably comfortable with the VARCHAR2, NUMBER and TIMESTAMP data types. And that’s a good thing, familiarity with those three data types will take you a long way into a… Read more
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02 February 2017
02 February 2017

Oracle for Absolute Beginners: Date, Timestamp and Interval

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All databases stand on a tripod of datatypes: strings, numbers and dates. And though they might dress them in fancy clothing – varchar2, clob, float, integer – strings are really just strings, and numbers are really just numbers. But dates — dates are interesting. In this article I’ll talk to you about dates, about time, and about how both ar… Read more
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02 September 2016
02 September 2016

JSON For Absolute Beginners: Part 2 – Why Use Oracle?

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In this short series of articles, we’ll be talking about JSON and its integration with the Oracle database.  The first part was an introduction to JSON itself, and was, admittedly, very light on Oracle.  But now it’s probably time to bring Oracle more into the story and talk about how the database has adapted to handle this new format. Or, actually,… Read more
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12 April 2016
12 April 2016

XQuery for Absolute Beginners: Part 4 – Conditions & Custom Functions

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This is the fourth part of a series introducing Oracle developers to XQuery. In the first three parts we’ve talked about XPath, Oracle’s implementation of XQuery, and FLWOR. This article won’t be taking on anything so meaty; I just want to clear up some odds and ends that I think are important, but I wasn’t able to shoehorn into any… Read more
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21 March 2016
21 March 2016

XQuery for Absolute Beginners: Part 3 – FLWOR

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This is the third instalment in a series of articles that I’m hoping will serve as a primer for Oracle developers interested in learning about Xquery. And – confession time – I’ve left the best part for last. However, you really should start with Part 1. Good things come to those who wait. In the first article we talked about… Read more
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09 November 2015
09 November 2015

Multi-Table Insert Statements in Oracle

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We all know this: if a long-bearded prophet came down from a mountaintop bearing the ten commandments of Oracle programming, one of them might read thus: Thou canst select from many tables, but thou may only update, delete from or insert into one table at a time. Right? Well, not exactly. Because you can actually add data to multiple tables… Read more
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30 September 2015
30 September 2015

Introduction to User-Defined Aggregate Functions

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OK, let’s speed past the easy bits, the parts we all already know: standard aggregate functions. Aggregate functions, unlike regular functions, take values from multiple rows as their input. The category includes those aggregate functions that are so ordinary they’re almost invisible – SUM, COUNT, MAX – and a couple that most of us never use – such as APPROX_COUNT_DISTINCT… Read more
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17 September 2015
17 September 2015

Introduction to Analytic Functions (Part 2)

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In the first part of this series I introduced you to the analytic functions family, outlined its close relationship to aggregate functions, and illustrated my points with a few examples. I demonstrated how, by clever use of the analytic function clauses – partition by, order by, and the windowing clause – you could tune your functions to wring even mor… Read more
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07 September 2015
07 September 2015

Introduction to Analytic Functions (Part 1)

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Analytic functions have been part of Oracle for a very long time now – ever since 8i back in 1999. Analytic functions are an ANSI/ISO standard, and so you’ll find that they are similarly-implemented across a number of compliant databases. (This SQL Server article on “window functions” from sister site, Simple Talk, could very well have been talking about Oracle.) Analytic… Read more
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