Two weeks into lockdown and some are looking to break the monotony by varying their diet…
For my part, I’ve decided to amuse myself by making a couple of “Top five” lists – the five best things about the lockdown and five things I’ve now finally got time to watch.
These lists are in text files are somewhere on my Database server and therefore provide the basis for the examples that follow.
When using Oracle, if you find yourself in a situation where you don’t have access to the Database Server file system, or would just rather use SQL to find what you’re looking for in a data set, you’re in luck.
The technique that used to be a neat way of viewing the database alert log from inside the database can now be re-purposed to look at any text file that’s located in a directory referenced by a Directory Object in the database.
What we’re going to look at here is :
Setting up an external table for reading from files
How to point the external table specific files and directories using EXTERNAL MODIFY
How achieve the same thing in 11gR2 databases with the help of DBMS_LOCK
Cute and fluffy he may be, but he’s got to earn his keep. He can start making himself useful by helping me with this post.
It begins one Friday afternoon when an urgent request lands on my desk with a large splat.
The requirement is that some csv files be uploaded into the Oracle 11g Datbasae serving the UAT environment to facilitate some testing.
There are around 20 files, each with a slightly different set of attributes.
The files are currently sitting on the on the Red Hat Linux Server hosting the database.
I have sufficient OS permissions on the server to move them to a directory that has a corresponding database object in the UAT instance.
Nevertheless, the thought of having to knock out 20-odd external tables to read these files might leave me feeling a bit like this…
Fortunately, a certain Lee E. McMahon had the foresight to predict the potential risk to my weekend and wrote the Stream Editor (sed) program…
The World Cup is finally over and “It’s Coming Home !”
For quite a long time, we English laboured under the illusion that “it” was football.
Fortunately for Scots everywhere, “It” turned out to be the World Cup which, like so many international sporting competitions, was conceived in France.
Another area that is often subject to flawed assumptions is what privileges are required to provide read-only access for someone to provide support to an Oracle Application.
So, for any passing auditors who may be wondering why “read only” access to an Oracle application sometimes means Write, or even Execute on certain objects…
In the aftermath of the Brexit vote, I’m probably not alone in being a little confused.
Political discourse in the UK has focused on exactly who it was who voted to Leave.
The Youth Spokesperson you get on a lot of political programs right now, will talk accusingly of older voters “ruining” their future by opting to Leave.
Other shocked Remainers will put it down to people without a University Degree.
I’m not sure where that leaves me as someone who is ever so slightly over the age of 30, does not have a degree…and voted to Remain. I’m pretty sure I’m not Scottish…unless there’s some dark family secret my parents haven’t let me in on.
I suppose I must be a member of the “Metropolitan Elite” the Leave side was always muttering darkly about.
After all, I do pay a great deal of money to be driven from my country residence to London to work every day…although I do have to share the train with the odd one or two fellow elitists who’ve made the same extravagant choice.
This does of course assume that Milton Keynes qualifies as being “in the country” and that my living there is a matter of choice rather than a question of being able to afford living any closer to London.
With all the excrement…er…excitement of the Referendum Campaign and it’s aftermath, I somehow never got around to writing my application to track the progress of the Euros (or the Copa America for that matter).
Whenever a major football tournament comes around, I always resolve to do this, if only to evoke memories of my youth when a large part of my bedroom wall was taken up with a World Cup Wallchart where you could fill in the results as they happened. That’s without mentioning the months leading up to the tournament and trying to complete the Panini collection – the only time you’d ever hear a conversation such as “OK, I’ll let you have Zico in exchange for Mick Mills”.
In order to prevent this happening again, I’ve resolved to write an application capable of holding details of any major international football tournament.
In the course of writing this application, I’d like to take the opportunity to have a look at an aspect of PL/SQL development that maybe isn’t as commonly used as it should be – Unit Testing.
Over the next few weeks, I plan to take a look at some of the Testing Frameworks available for PL/SQL and see how they compare.
The objective here is not so much to find which framework is the best/most suitable, but to perform an objective comparison between them using the same set of tests which implement fairly commonly encountered functionality.
In this post, I’ll be outlining the functionality that I’ll be testing in the form of User Stories, together with the application data model (or at least, the bit of it I need to execute the tests).
I’ll also have a look at the common pattern that tests written in these frameworks tend to follow.
Just to highlight why using a Test Framework might be useful, I’ll also script a couple of simple tests in SQL to see just how much code you have to write to implement tests without using a framework. Continue reading →
It’s General Election time here in the UK.
Rather than the traditional two-way fight to form a government, this time around we seem to have a reasonably broad range of choice.
In addition to red and blue, we also have purple and – depending on where you live in the country, multiple shades of yellow and green.
The net effect is to leave the political landscape looking not so much like a rainbow as a nasty bruise.
The message coming across from the politicians is that everything that’s wrong in this country is down to foreigners – Eastern Europeans…or English (once again, depending on your location).
Strangely, the people who’ve been running our economy and public services for the last several years tend not to get much of a mention.
Whatever we end up choosing, our ancient electoral system is not set up to cater for so many parties attracting a significant share of support.
The resulting wrangling to cobble together a Coalition Government will be hampered somewhat by our – equally ancient – constitution.
That’s largely because, since Magna Carta, no-one’s bothered to write it down.
In olden times, if you wanted to find out what files were in a directory from inside the database, you’re options were pretty undocumented as well.
Fortunately, times have changed…
What I’m going to cover here is how to use an External Table pre-process to retrieve a file listing from a directory from inside the database.
Whilst this technique will work on any platform, I’m going to focus on Linux in the examples that follow… Continue reading →
So, the World Cup is in full swing.
Now the lesser teams have fallen by the wayside ( England), we can get on with enjoying a feast of footie.
As well as a glut of goals, the current tournament has given us a salutory reminder of the importance of diet for elite athletes.
After predictably (and brilliantly) destroying England single-handedly, Luis Suaraz found himself a bit peckish and nipped out for an Italian. Now the whole world seems to be commenting on his eating habits.
Like Luis, you may find yourself thinking that you’ve bitten off more than you can chew when confronted by DBMS_DATAPUMP.
The documentation does offer some help…to an extent. However, the whole thing can seem a bit fiddly, especially if you’re used to the more traditional command-line interface for Datapump.
What follows is a tour through DBMS_DATAPUMP based on my own (sometimes painful) experience, broken down into bite-sized chunks.
Much of the functionality to filter object types and even data is common to both Exports and Imports.
So, the approach I’ve taken is to cover the Export first, with a view to finally producing a Full Database export.
I’ve then used the Import process against this to demonstrate some of the package’s filtering capabilities.
So, what’s on the menu today ?
Privileges required to run a DBMS_DATAPUMP job from your current schema and for the whole database
Running a consistent export
Running datapump jobs in the background
Monitoring running jobs
Importing from one schema to another
Specifying the types of objects to include in Exports and Imports
Specifying subsets of data
DDL only Jobs
How to Kill a Datapump Job
The full code examples have all been written and tested on Oracle XE 11gR2.
I’ve tried to maximise the use of in-line hard-coded values and minimise the number of variables in an attempt to make the code easier to follow.
Also, in these examples I’ve made use of the default DATA_PUMP_DIR directory object, but you can use any directory object to which you have the appropriate privileges.
For dessert, there are a couple of other DBMS_DATAPUMP features that I have found useful that are specific to Enterprise Edition ( in one case, with the Partitioning Option) ;