klog

Overview: Learning PHP Data Objects, by Dennis Popel, is an introduction to PDO, which walks through the building of a believable test example - a library manager for your home library. Each chapter introduces a new facet of PDO and shows how to rewrite the appropriate parts of the application to slot the new ideas in. Very clear and easy to read. Non-PDO subjects are appropriately kept to the appendices.

I really couldn’t find very much about this book that I didn’t like. Ignoring the appendices, the book is 154 pages purely devoted to teaching PDO through examples, including error handling, working with BLOBs, even the creation of the M in MVC (Models).

I mentioned MVC there. One of my gripes with most tutorials of MVC is that they introduce the concept simply, then provide pages and pages of code with the end product which is “hello world”. Why I should go to all that trouble instead of simply writing <php echo 'hello world'; ?> to the screen usually escapes me. Dennis, however, concentrates solely on the Model and shows exactly why it’s a great idea. I think some more separation of concerns would have been better (don’t mix Author and Book SQL in the same object, for example), but the ideas were all good.

I think that if Dennis was going to show how the Model works, he should also have gone a little further and showed an example of an Active Record pattern as well. But I guess the point of showing MVC was more to show /an/ example of abstraction of the DB code, and that was sufficient.

The book covers a Library manager application all the way through from conception to implementation, demonstrating at all points that the code works with SQLite and MySQL (and by implication, all other DBMS’s) with a change of only the connection string.

Possible problems are explained clearly and solutions are provided. For example, Dennis explains why, after you compile the query select * from books, PDO (and indeed the database itself) does not know how many rows it will return. A solution, in the form of a very smart getRowCount() function shows a query-agnostic method for counting results of an arbitrary line of SQL.

Other areas that are covered in the book include error-handling, prepared statements and transaction-handling.

PDO can handle Prepared Statements even if the underlying DBMS cannot handle it, so it is possible to write your code in a cross-platform way. Examples of why you should use this are provided. One of the examples shows an efficient way to handle insertion or updating of a table using the same parameters for both cases, with the row-handling function deciding whether to use update or insert based on whether an ID was provided.

I feel the Transactions section could have been expanded a bit further. It is not explained how PDO handles this for DBMS’s that don’t internally support transactions, and I wouldn’t like to assume that they work all the time, only to find after deleting critical data that it’s not supported.

Overall, I enjoyed reading this book. Dennis is a good writer and I think he explained his thoughts very clearly.

On an aside, my four-year-old son Jareth loves Packt Publishing’s books. Sometimes when I go to read another chapter, I need to covertly steal the book I’m reading back from him. For a while, he made it a bed-time ritual to grab all the Packt books he could find around and bring them up with him to read in bed. I think he loved the screen-shots and the frequent code samples. He’s high-functioning autistic and likes literary constructs, and programming books are perfect for him in that regard. Thanks Packt, you’ve made my son (and therefore me) happy.

Packt publishing emailed me a week ago and asked me if I was interested in writing a review of a book on phpMyAdmin.

In short, my review is this: overall, the book detailed everything I can think of (and more) about phpMyAdmin - I learned about some features in phpMyAdmin that I was not already aware of. I would ask for less screenshots, more how-tos and less “we/our” speech for the next revision, but if there are any questions I have about phpMyAdmin, the answers are in this book.

I use phpMyAdmin only occasionally, when I can’t get direct access to the database in question (I’m a console jockey - there’s nothing like the thrill of tappity-tapping away, knowing that you’re doing Important Stuff and …well, yeah - geek).

I’ve used phpMyAdmin since forever, so was familiar with its common uses - importing/exporting databases, running simple queries, etc. I was interested to see if there was anything that I might have missed. And who better to show me than one of the developers, Marc Delisle.

The table of contents was large, spread over 12 pages. I feel it would have been easier to read if there was one page detailing just h1 listings, followed by 2-3 pages of h2 listings. The h3 and h4 listings could have been shown at the beginning of the concerned chapters.

Disregarding that, scanning the contents showed some features that I was not aware of. Did you know that phpMyAdmin has a built-in relations manager? Even if the engine used is MyISAM, which does not manage referential integrity, phpMyAdmin will protect you and manage it for you if queries are run through it.

Screenshots are provided for everything. This makes some things much easier to understand. Sometimes it made interesting features stand out even more. Did you know that phpMyAdmin can generate PDFs of the relational schema of a database? Some screenshots in chapter 15 show examples of this feature.

Marc obviously knows his stuff. As a major contributor to phpMyAdmin since the early days, he is an ideal person to talk us through configuration details and the various tools that phpMyAdmin offers.

There are, however, a number of things which detract from the readability of the book.

This is the first edition for this title, so the following are probably “teething” problems for the author. However, I think they should be taken care of for the second edition, to make the book easier to read. Although, the second edition would most likely have a different title (why is the version number in the title?)

The book is written from a 1st-person-plural point of view - now we do this, now we do that, our table, our server. This distracted and annoyed me while reading the book.

It is too detailed in places, at the expense of readability. For example, chapter one goes through a blow-by-blow account of how phpMyAdmin came to be, with version numbers and even dates! I feel this should have been left to an appendix. The first chapter of any book should introduce a reader gently to the subject; not pummel the reader with historical facts.

The author sometimes forgets that the reader does not know the subject and its community’s habits. As an example, on page 28 the configuration value “PmaAbsoluteUri” is described, but afterwards, I was not sure a) what “Pma” is, or b) what the variable was supposed to do (the book described how it should be configured, but not what it was supposed to do). It isn’t until page 33 that the book pointed out that “pma” is an acronym for “phpMyAdmin” used by the community. I don’t feel stupid for not getting this immediately, as there is an awkward mixture of letter-cases going on there. By rights, “Pma” should stand for “Phpmyadmin”, not “phpMyAdmin”.

The sheer number of screenshots was a bit confusing. I feel that screenshots should only be used where the subject is not clear from the text. Two images on every page (almost) has the effect of breaking your concentration when you’re trying to read.

The book exclusively deals with how to use phpMyAdmin, but I think there should have been more about how to deal with MySQL itself, using phpMyAdmin. For example, chapter 17 details phpMyAdmin’s coverage of character sets and collations. As a person who knows the pain of upgrading a database from MySQL 4 to MySQL 5 while switching character sets, I was looking forward to seeing how this case is handled (which I am sure is pretty common in one form or another). However, the chapter describes the problems with character sets and does not offer any solutions to those problems.

Overall, the book was detailed, and I learned a lot of new stuff from it. I’d recommend it for administrators that are not comfortable with CLI MySQL and want a reference for the best web-based MySQL administration tool out there.

I’ve been doing well over the last two weeks - I started with an ANN which can balance a pole, and upped that by then creating a net which could recognise letters.

The plan for today is a bit more ambitious. I’m writing it down here in case it takes longer than a day to write it. In general, I want to write a PHP application which will allow you to upload images, which the ANN will then try to recognise. If it gets it right, all well and good. If it gets it wrong, you can correct it.

Some milestones for the project:

• readers can upload images and have them tested and/or added to the training sequence
• extraction of image pixels using <canvas>
• automatic creation of new neurons as they are required
• best net is stored on server, so new readers always start with a working net

I think this may grow into a damned cool thing - I’m already thinking of other cool features like distributed nets, or background nets which can be placed in other pages of a site so the thing can continue training even though the user is not actively viewing the thing (that might be a bit cheeky though).

Anyway - now that I’ve written what I intend to do, I suppose I’d better actually do it.