“Beginning MySql” – Book Review


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Here’s a book review I did on amazon.com.
Check out more of my reviews at my amazon.com profile page.

Overall, I love this book, because the authors build your knowledge of databases from the ground up.

Before I got my hands on this book, I knew only a limited amount about databases. Now, I understand advance concepts (like foreign keys, transactions and optimization) and can design, implement and maintain my own simple relational database management system.

This is a thick book that took me about 2 weeks to finish and it would have taken even longer if I decided to follow through with all the “Try it out” sections, exercises and useful examples.

“Beginning MySql” covers the majority of MySql 4.1 by using the definitions of syntax and options as their main teaching tool throughout most of the chapters. This makes MySql easy to learn since you can reference the definitions as a cheat sheet when you’re implementing a database design.

One thing that I noticed is that they need more proofreading. Every now and then, you’ll encounter a typo or wrong information but this is expected since the authors warned of this in the introduction.
Example, page 299: “However, bitwise operations support calculations up to 64 buts”.

The best part of the book, is appendix C. It briefly covers MySql 5 but they introduce you to Triggers, Views and Procedures while updating you on MySql new standards. For exmaple, MySql 5 supports foreign keys for all the table engines, not just for INNODB.
If you’re the type that has a hard time reading documentation online, then I would strongly recommend this book. Otherwise you might be able to learn MySql using Youtube and the MySql homepage.

Note: Since this book only converts version 4.1 of MySql, you need to checkout the on-line documentation for changes in MySQL 5.

You can buy the book for less than $10. Link below.

Larry Battle

Larry Battle

I love to program, and discover new tech. Check out my <a href="http://stackoverflow.com/users/527776/larry-battle">stackoverflow</a> and <a href="https://github.com/LarryBattle">github</a> accounts.

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Javascript Code of the Day: get highlighted text


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Discovered the code below while browsing online. Inspired from codetoad.com.

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function getHighlightedText(){
     return ((window.getSelection) ? window.getSelection() 
          : (document.getSelection) ? document.getSelection()
          : (document.selection) ? document.selection.createRange().text 
          : null);
}

Usage

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getHighlightedText();   // returns highlighted material as a string.
Larry Battle

Larry Battle

I love to program, and discover new tech. Check out my <a href="http://stackoverflow.com/users/527776/larry-battle">stackoverflow</a> and <a href="https://github.com/LarryBattle">github</a> accounts.

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Google Translate a Life Saver

Google Translate Mobile App
Google Translate Mobile App

Four days after a powerful earthquake-triggered tsunami hit the Japan’s east coast, I found a this on Google, Google Translate for Android Phones.

A few years back, I studied aboard in Japan. In the beginning, it wasn’t easy living there, since I only knew the very basics of the language. The part that made it even harder was that even though I studied for countless hours, I still had a hard time understanding what they said. But eventually, with time, the words and phrases started to come together and make more sense.

During my time aboard, I’ve lived in Taiwan and Japan and Google’s Mobile App Google Translate would have a been a life saver. There’s even a mobile app called Google Goggles for the Android Phone that allows you to translate text capture by your camera into your choice of language.
I’m astonished by the technological advancement made in natural language processing and voice recognition. Those two applications would have helped me open up more and get a better grip on what’s going on around me.

I recommend these two application for anyone adventuring to a foreign county.

My Pictures from Japan and Taiwan


Yamagata University in Japan
Yamagata University in Japan

Taiwanese Temple
Taiwanese Temple

Flickr Study Aboard Taiwan's Mountain View
Flickr Study Aboard Taiwan's Mountain View

Driving in Taiwan
Driving in Taiwan

Funny Videos using Google Translate


Learn Japanese with Minna no Nihongo. Link below.

Please leave your comments below.

Larry Battle

Larry Battle

I love to program, and discover new tech. Check out my <a href="http://stackoverflow.com/users/527776/larry-battle">stackoverflow</a> and <a href="https://github.com/LarryBattle">github</a> accounts.

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JavaScript Binary Operations – the easy way

Intro:

“There are 10 types of people in this world. Those who understand binary and those who don’t” – Author Unknown

Javascript is loaded with hidden features that can that be used for more than DOM manipulation and event handling. Javascript supports binary operations pretty well, and now I’m going to show you how to master them.
By the end of this tutorial you will learn the following.

  • Base Conversions
  • Bitwise operations
  • Logic Gates

For better comprehension, I recommend that you use a Javascript Console, which is available in Firebug ( a Firefox addon) or in Google Chrome Dev Tools. If you wish, you can even use online editors, like jsbin.com and jsfiddle.net, to follow along.
Note: Negative numbers will not be dealt with in this tutorial, since Javascript doesn’t support signed bits.

Definitions:

For those that are new to the binary concept, watch the following short videos to catch up then continue.

Decimal, Binary, Octal, and Hexadecimal

Hexadecimal – learn it in less than a minute

Boolean Algebra: AND/OR/NOT

Javascipt Code:

Base Conversion: For positive numbers
The toString() and parseInt() functions will be your friends in this section.
(number).toString( [baseTo] ) will change a number to a string type. If a base is provided in the toString argument, then the number gets converted to a new base from 2 – 36.
Example:

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// number.toString( [ baseTo ] ); returns number in desired base.
(3).toString( 2 ); 		// returns "11"
(54).toString( 2 );		// returns "110110"
(120).toString( 16 );		// returns "78"

Additionally, hexadecimal numbers( base 16) can be represented with a prefix of “0x”.
While a prefix of “0” denotes an Octal number( base 8).
Example:

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var hex = 0xFF		// hex is 255 in decimal
hex = 0x01 		// now hex is 1 in decimal
var oct = 013		// oct = 11

Alternatively, parseInt( { number | string }, [baseFrom] ) will parse a number or a string that contains a number, and convert the bases, with the default base set to 10. Please be aware that you the base must be between 2 – 36.
Example:

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// parseInt( { number | string }, [ baseFrom ] ); returns decimal number.
num = "110110";
parseInt( num );		// displays 110110 because default base 10.
parseInt( num, 2 );		// displays 54
parseInt( "dad", 16 );		// displays 3501, "dad" is valid hex;
 
var hex = "badDad";	
parseInt( hex, 16 );		// returns 12246445
+("0x"+ hex );			// returns 12246445 (Alternative way to parse hex.)

Ok, so your next question might be how to convert from one base to another, like from Binary to Hexadecimal. To achieve your goal, convert base A to decimal then to base B.
For those seeking a function to encode and decode bases higher than 36, check out this script at Snipplr.com

Example:

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// Convert from baseA( Binary ) to baseB( Hexadecimal). 
// Note: Both baseA and baseB must be between 2 and 36.
var baseA = 2, baseB = 16;
var binary = 1010111, hex, dec;
dec = parseInt( binary, baseA );		// dec = 87
hex = dec.toString( baseB );		// hex = 57

Thankfully, you can simplify all the base conversion to one simple function, which I call convertNumToBase.

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// Convert from baseA to baseB
// Note: Both baseA and baseB must be between 2 and 36.
var convertNumToBase = function( num, baseA, baseB ){
	if( !( baseA < 2 || baseB < 2 || isNaN( baseA ) 
		|| isNaN(baseB) || baseA > 36 || baseB > 36) ){
        return parseInt( num, baseA ).toString( baseB );
    }
};	
convertNumToBase( 1111, 2, 10 );		// return "15"
convertNumToBase( 10101111, 2, 16 );		// return "af"
convertNumToBase( "FF", 16, 2 ); 		// return "11111111"

Sometimes, it might be useful to have a binary string with a fixed number of bits.
We can implement this with an extension to the previous example.

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var getStrCopy = function (str, copies) {
	var newStr = str;
	copies = (copies > 0) ? copies : 1;
	while (--copies) {
		newStr += str;
	}
	return newStr;
},
convertDecToBase = function ( dec, base, length, padding ) {
	padding = padding || '0' ;
	var num = dec.toString( base );
	length = length || num.length;
	if (num.length !== length) {
		if (num.length < length) {
			num = getStrCopy( padding, (length - num.length)) + num;
		}
		else {
			throw new Error("convertDecToBase(): num(" + num + ").length > length(" + length + ") too long.");
		}
	}
	return num;
};
 
// Usage
convertDecToBase( 23, 2, 8 );            //returns "00010111"
convertDecToBase( 23, 2, 8, 'x' );       //returns "xxx10111"

Two’s Complement
Javascript designates the character tilde, ~, for the two’s complement, even though in most programming languages tilde represents a bit toggle for the one’s complement.

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var num = 70;
~num;			// returns -71
~num.toString(2);	// returns -1000111

I’ve already covered this feature in a previous article titled, “Javascript NOT is not what you expect”.

Proper Binary Format
To make binary easier to read, modify the every four digits by either placing a space after them or converting them to hex.

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binaryStr = "1110001100110001";
binaryStr.replace( /\d{4}/g, '$& ' ).replace( /\s$/,'') // return "1110 0011 0011 0001"
parseInt( binaryStr, 2).toString( 16 );                   // returns "e331"

Bitwise operations
Bitwise operations are covered in great details at Wikipedia: Bitwise Operations.
But if you don’t want to read that then watch this video.
Note: Remember Javascript’s tilde, ~, returns the two’s complement.

Example:

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clear();
var a = parseInt( "1010", 2 );	// a = 10
var b = parseInt( "1100", 2 );	// b = 12
 
(a & b).toString(2);		// a AND b returns dec = 8, binary = 1000
(a | b).toString(2);	        // a OR b returns dec = 14, binary = 1110
(a ^ b);    		        // a XOR b returns dec = 6, binary = 0110
 
//Invalid binary number because of the negative sign.
~b.toString(2);     		// a NOT returns dec = -13, binary = "-1101"
(~( a & b )).toString(2); 	// a NAND b returns dec = -7, binary = "-1001"
(~( a | b )).toString(2);	// a NOR b returns dec = -15, binary = "-1111"
~( a ^ b );                	// a NXOR b returns dec = -7, binary = "-1001"
 
var num = 13; 		        // 13 is "1101" in binary;
var position = 3;
 
// access bit position
(num >> position).toString(2)		// returns 1
(num >> position) & 0x01;		// returns 1
num.toString(2).charAt( position );	// Alternative method, returns '1'
 
// set a bit
( 1 << position ).toString(2);		// returns "1000"
num &= ( 1 << position );		// returns  8, binary "1000"
 
// clear a bit
( 0 << position ).toString(2);		// returns "1000"
num &= ( 0 << position );		// returns 0
 
// Toggle a bit
num ^= ( 1 << position );		// returns 8, binary = "1000"
 
// Test a bit
(num >> position) & 1;			//returns 1
 
// left shift with 0's
num >>> position;			// returns 1
 
// right shift with 0's
num << position;			// returns 64, binary = "1000000"

Conclusion:

Javascript is a powerful language that many hidden features that waiting to be discovered.
Even though bitwise operations are rarely used in projects, it’s still useful to know.
This concludes the tutorial.

Test your knowledge. Take the quiz below!
Binary Quiz ( made with jQuizMe)

References:

Bitwise Operators
More Geeky quotes
Javascript’s Global Objects
Wikipedia Bitwise operations


Larry Battle

Larry Battle

I love to program, and discover new tech. Check out my <a href="http://stackoverflow.com/users/527776/larry-battle">stackoverflow</a> and <a href="https://github.com/LarryBattle">github</a> accounts.

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