· ezSQL is a widget that makes it very fast and easy for you to use database(s) within your PHP scripts ( mySQL / Oracle8/9 / InterBase/FireBird / PostgreSQL / MS-SQL / SQLite / SQLite c++).
· It is one php file that you include at the top of your script. Then, instead of using standard php database functions listed in the php manual, you use a much smaller (and easier) set of ezSQL functions.
· It automatically caches query results and allows you to use easy to understand functions to manipulate and extract them without causing extra server overhead
· It has excellent debug functions making it lightning-fast to see what’s going on in your SQL code
· Most ezSQL functions can return results as Objects, Associative Arrays, or Numerical Arrays
· It can dramatically decrease development time and in most cases will streamline your code and make things run faster as well as making it very easy to debug and optimise your database queries.
· It is a small class and will not add very much overhead to your website.
Note: It is assumed that you are familiar with PHP, basic Database concepts and basic SQL constructs. Even if you are a complete beginner ezSQL can help you once you have read and understood this tutorial.
Note: In all these examples no other code is required other than including ez_sql.php
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// Select multiple records from the database and print them out..
$users = $db->get_results("SELECT name, email FROM users");
foreach ( $users as $user )
{
// Access data using object syntax
echo $user->name;
echo $user->email;
}
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// Get one row from the database and print it out..
$user = $db->get_row("SELECT name,email FROM users WHERE id = 2");
echo $user->name;
echo $user->email;
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// Get one variable from the database and print it out..
$var = $db->get_var("SELECT count(*) FROM users");
echo $var;
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// Insert into the database
$db->query("INSERT INTO users (id, name, email) VALUES (NULL,'justin','jv@foo.com')");
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// Update the database
$db->query("UPDATE users SET name = 'Justin' WHERE id = 2)");
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// Display last query and all associated results
$db->debug();
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// Display the structure and contents of any result(s) .. or any variable
$results = $db->get_results("SELECT name, email FROM users");
$db->vardump($results);
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// Get 'one column' (based on column index) and print it out..
$names = $db->get_col("SELECT name,email FROM users",0)
foreach ( $names as $name )
{
echo $name;
}
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// Same as above ‘but quicker’
foreach ( $db->get_col("SELECT name,email FROM users",0) as $name )
{
echo $name;
}
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// Map out the full schema of any given database and print it out..
$db->select("my_database");
foreach ( $db->get_col("SHOW TABLES",0) as $table_name )
{
$db->debug();
$db->get_results("DESC $table_name");
}
$db->debug();
When working with databases most of the time you will want to do one of four types of basic operations.
1. Perform a query such as Insert or Update (without results)
2. Get a single variable from the database
3. Get a single row from the database
4. Get a list of results from the database
ezSQL wraps up these four basic actions into four very easy to use functions.
bool $db->query(query)
var $db->get_var(query)
mixed $db->get_row(query)
mixed $db->get_results(query)
With ezSQL these four functions are all you will need 99.9% of the time. Of course there are also some other useful functions but we will get into those later.
Important Note: If you use ezSQL inside a function you write, you will need to put global $db; at the top.
To install ezSQL download, unzip and install the contents of ez_sql.zip into the same directory within your web server.
Before you can use ezSQL you need to set 4 basic settings within ez_sql.php. They can be found at the top of the ez_sql.php file. They are:
define("EZSQL_DB_USER", ""); <-- mysql db user
define("EZSQL_DB_PASSWORD", ""); <-- mysql db password
define("EZSQL_DB_NAME", "mysql"); <-- mysql db name
define("EZSQL_DB_HOST", "localhost"); <-- mysql server host
Actually you probably only need to worry about the first three values since on most systems localhost will be fine for the dbhost value. If you are unsure about any of the above settings you should contact your provider or look through your providers documentation.
If you are running on a local machine and have just installed mySQL for the first time, you can probably leave the user name and password empty ( i.e. = “”) until you set up a mySQL user account.
Once you have installed ezSQL as described above you can see it in action by running ez_demo.php via your web browser. To do this simply go to..
http://yourserver.com/install_path/ez_demo.php
If you are running your web server on your local machine this will be..
http://127.0.0.1/install_path/ez_demo.php
What the demo does… is use ezSQL functions to map out the table structure of your database (i.e the database you specified at the top of ez_sql.php). You will be surprised how little code is required to do this when using ezSQL. I have included it here so you can get a quick feel for the compactness and speed of ezSQL.
<?php
include_once "ez_sql.php";
$my_tables = $db->get_results("SHOW TABLES",ARRAY_N);
$db->debug();
foreach ( $my_tables as $table )
{
$db->get_results("DESC $table[0]");
$db->debug();
}
?>
<?php
This is the standard way to start php executing within your web page.
include_once “ez_sql.php”;
This is how you include ezSQL in your script. Normally you include it at the top of your script and from that point forward you have access to any ezSQL function.
$my_tables = $db->get_results(“SHOW TABLES”,ARRAY_N);
get_results() is how you get ‘a list’ of things from the database using ezSQL. The list is returned as an array. In this case the std mySQL command of ‘SHOW TABLES’ is called and the resulting list is stored in a newly created array $my_tables.
When using $db->get_results(), if there are any results, they are always returned as multi-dimensional array. The first dimension is a numbered index. Each of the numbered indexes is either an object, associative array or numerical array containing all the values for ‘one row’.
For example using the switch ARRAY_A would produce an array that looked something like this.
$users = $db->get_results(“SELECT id,name FROM users”,ARRAY_A);
$users[0] = array (“id” => “1”, “name” => “Amy”);
$users[1] = array (“id” => “2”, “name” => “Tyson”);
If you wanted a numerical array use the switch ARRAY_N.
$users = $db->get_results(“SELECT id,name FROM users”,ARRAY_N);
$users[0] = array (0 => “1”, 1 => “Amy”);
$users[1] = array (0 => “2”, 1 => “Tyson”);
If you wanted an object (which is the default option) you don’t need a switch..
$users = $db->get_results(“SELECT id,name FROM users”);
$users[0]->id = “1”;
$users[0]->name = “Amy”;
$users[1]->id = “2”;
$users[1]->name = “Tyson”;
Results returned as an object make it very easy to work with database results using the numerous array functions that php offers. For example, to loop through results returned as an object all one needs to do is..
$users = $db->get_results(“SELECT id,name FROM users”);
foreach( $users as $user )
{
echo $user->id;
echo $user->name;
}
If you are 100% sure that there will be results you can skip a step and do this..
foreach( $db->get_results(“SELECT id,name FROM users”) as $user )
{
echo $user->id;
echo $user->name;
}
If you don’t know whether there will be results or not you can do this..
If ( $users= $db->get_results(“SELECT id,name FROM users”) )
{
foreach( $users as $user )
{
echo $user->id;
echo $user->name;
}
}
else
{
echo “No results”;
}
$db->debug();
This function prints the most recently called sql query along with a well formatted table containing any results that the query generated (if any) and the column info.
foreach ( $my_tables as $table)
This is the standard way to easily loop through an array in php. In this case the array $my_tables was created with the ezSQL command $db->get_results(“SHOW TABLES”,ARRAY_N). Because of the ARRAY_N switch the results are returned as a numerical array.
The resulting array will look something like..
$my_tables[0] = array (0 => “users”);
$my_tables[1] = array (0 => “products”);
$my_tables[2] = array (0 => “guestbook”);
{
The foreach is looping through each primary element of $my_tables[n] which are in turn numerical arrays, with the format like so..
array(0 => “value”, 1 => “value”, etc.);
Thus, during the foreach loop of $my_tables we have access to the value of the first column like so:
foreach ($my_tables as $table)
{
echo $table[0];
}
If we did the same thing using an associative array it might look like this..
$users = $db->get_results(“SELECT id,name FROM users”,ARRAY_A);
foreach ( $users as $user )
{
echo $user[‘id’];
echo $user[‘name’];
}
But if there were no results foreach might generate a warning. So a safer way to do the above is..
if ( $users = $db->get_results(“SELECT id,name FROM users”,ARRAY_A))
{
foreach ( $users as $user )
{
echo $user[‘id’];
echo $user[‘name’];
}
}
else
{
echo “No Users”:
}
This works because if no results are returned then get_results() returns false.
$db->get_results(“DESC $table[0]”);
This database query is nested within the foreach loop. Note that we are using the results of the previous call to make a new call. Traditionally you would have to be concerned about using different db_resource identifiers in a case like this but ezSQL takes care of that for you, making it very easy to nest database queries.
You may be wondering why I have used a numerical array output and not object or associative array. The reason is because in this case I do not know what the name of the first column will be. So I can make sure that I can always get its value by using numerical array output and targeting the first column by element [0].
FYI: The SQL command SHOW TABLES always names the first column a different value depending on the database being used. If the database was named users the column would be called Tables_in_users if the database was called customers the column would be called Tables_in_customers and so on.
$db->debug();
This function will always print the last query and its results (if any) to the browser. In this case it will be for the above query..
$db->get_results(“DESC $table[0]”);
You may have noticed that the above get_results function is not assigning a value. (i.e. $var = val). This is because even if you do not assign the output value of any ezSQL function the query results are always stored and made ready for any ezSQL function to use. In this case $db->debug() is displaying the stored results. Then, by calling any ezSQL function using a null query you will be accessing the stored results from the last query. Here is a more detailed example.
Users Table..
amy, amy@foo.com
tyson, tyson@foo.com
// Any ezSQL function will store query results..
$users = $db->get_results(“SELECT name,email FROM users”);
// This gets a variable from the above results (offset by $x = 1, $y = 1).
echo $db->get_var(null,1,1);
// Note: Because a null query is passed to get_var it uses results from the previous query.
Output: tyson@foo.com
}
This closes the foreach loop
?>
This stops php executing code
ezSQL functions
$db->get_results -- get multiple row result set from the database (or previously cached results)
$db->get_row -- get one row from the database (or previously cached results)
$db->get_col -- get one column from query (or previously cached results) based on column offset
$db->get_var -- get one variable, from one row, from the database (or previously cached results)
$db->query -- send a query to the database (and if any results, cache them)
$db->debug -- print last sql query and returned results (if any)
$db->vardump -- print the contents and structure of any variable
$db->select -- select a new database to work with
$db->get_col_info -- get information about one or all columns such as column name or type
$db->hide_errors -- turn ezSQL error output to browser off
$db->show_errors -- turn ezSQL error output to browser on
$db->escape -- Format a string correctly to stop accidental mal formed queries under all PHP conditions
$db = new db -- Initiate new db object.
ezSQL variables
$db->num_rows – Number of rows that were returned (by the database) for the last query (if any)
$db->insert_id -- ID generated from the AUTO_INCRIMENT of the previous INSERT operation (if any)
$db->rows_affected -- Number of rows affected (in the database) by the last INSERT, UPDATE or DELETE (if any)
$db->num_queries -- Keeps track of exactly how many 'real' (not cached) queries were executed during the lifetime of the current script
$db->debug_all – If set to true (i.e. $db->debug_all = true;) Then it will print out ALL queries and ALL results of your script.
$db = new db
$db = new db -- Initiate new db object. Connect to a database server. Select a database.
$db = new db(string username, string password, string database name, string database host)
Does three things. (1) Initiates a new db object. (2) Connects to a database server. (3) Selects a database. You can also re-submit this command if you would like to initiate a second db object. This is interesting because you can run two concurrent database connections at the same time. You can even connect to two different servers at the same time if you want to.
Note: For the sake of efficiency it is recommended that you only run one instance of the db object and use $db->select to switch between different databases on the same server connection.
// Initiate new database object..
$db2 = new db(”user_name”, ”user_password”, ”database_name”, “database_host”);
// Perform some kind of query..
$other_db_tables = $db2->get_results(“SHOW TABLES”);
// You can still query the database you were already connected to..
$existing_connection_tables = $db->get_results(“SHOW TABLES”);
// Print the results from both of these queries..
$db->debug();
$db2->debug();
$db->select
$db->select -- select a new database to work with
Description
bool $db->select(string database name)
$db->select() selects a new database to work with using the current database connection as created with $db = new db.
// Get a users name from the user’s database (as initiated with $db = new db)..
$user_name = $db->get_var(“SELECT name FROM users WHERE id = 22”) ;
// Select the database stats..
$db->select(“stats”);
// Get a users name from the user’s database..
$total_hours = $db->get_var(“SELECT sum(time_logged_in) FROM user_stats WHERE user = ‘$user_name’”) ;
// Re-select the ‘users’ database to continue working as normal..
$db->select(“users”);
$db->query
$db->query -- send a query to the database (and if any results, cache them)
Description
bool $db->query(string query)
$db->query() sends a query to the currently selected database. It should be noted that you can send any type of query to the database using this command. If there are any results generated they will be stored and can be accessed by any ezSQL function as long as you use a null query. If there are results returned the function will return true if no results the return will be false
// Insert a new user into the database..
$db->query(“INSERT INTO users (id,name) VALUES (1,’Amy’)”) ;
// Update user into the database..
$db->query(“UPDATE users SET name = ‘Tyson’ WHERE id = 1”) ;
// Query to get full user list..
$db->query(“SELECT name,email FROM users”) ;
// Get the second row from the cached results by using a null query..
$user_details = $db->get_row(null, OBJECT,1);
// Display the contents and structure of the variable $user_details..
$db->vardump($user_details);
$db->get_var
$db->get_var -- get one variable, from one row, from the database (or previously cached results)
Description
var $db->get_var(string query / null [,int column offset[, int row offset])
$db->get_var() gets one single variable from the database or previously cached results. This function is very useful for evaluating query results within logic statements such as if or switch. If the query generates more than one row the first row will always be used by default. If the query generates more than one column the leftmost column will always be used by default. Even so, the full results set will be available within the array $db->last_results should you wish to use them.
// Get total number of users from the database..
$num_users = $db->get_var(“SELECT count(*) FROM users”) ;
// Get a users email from the second row of results (note: col 1, row 1 [starts at 0])..
$user_email = $db->get_var(“SELECT name, email FROM users”,1,1) ;
// Get the full second row from the cached results (row = 1 [starts at 0])..
$user = $db->get_row(null,OBJECT,1);
// Both are the same value..
echo $user_email;
echo $user->email;
// Find out how many users there are called Amy..
if ( $n = $db->get_var(“SELECT count(*) FROM users WHERE name = ‘Amy’”) )
{
// If there are users then the if clause will evaluate to true. This is useful because
// we can extract a value from the DB and test it at the same time.
echo “There are $n users called Amy!”;
}
else
{
// If there are no users then the if will evaluate to false..
echo “There are no users called Amy.”;
}
// Match a password from a submitted from a form with a password stored in the DB
if ( $pwd_from_form == $db->get_var(“SELECT pwd FROM users WHERE name = ‘$name_from_form’”) )
{
// Once again we have extracted and evaluated a result at the same time..
echo “Congratulations you have logged in.”;
}
else
{
// If has evaluated to false..
echo “Bad password or Bad user ID”;
}
$db->get_row
$db->get_row -- get one row from the database (or previously cached results)
Description
object $db->get_ row(string query / null [, OBJECT / ARRAY_A / ARRAY_N [, int row offset]])
$db->get_row() gets a single row from the database or cached results. If the query returns more than one row and no row offset is supplied the first row within the results set will be returned by default. Even so, the full results will be cached should you wish to use them with another ezSQL query.
// Get a users name and email from the database and extract it into an object called user..
$user = $db->get_row(“SELECT name,email FROM users WHERE id = 22”) ;
// Output the values..
echo “$user->name has the email of $user->email”;
Output:
Amy has the email of amy@foo.com
// Get users name and date joined as associative array
// (Note: we must specify the row offset index in order to use the third argument)
$user = $db->get_row(“SELECT name, UNIX_TIMESTAMP(my_date_joined) as date_joined FROM users WHERE id = 22”,ARRAY_A) ;
// Note how the unix_timestamp command is used with as this will ensure that the resulting data will be easily
// accessible via the created object or associative array. In this case $user[‘date_joined’] (object would be $user->date_joined)
echo $user[‘name’] . “ joined us on ” . date(“m/d/y”,$user[‘date_joined’]);
Output:
Amy joined us on 05/02/01
// Get second row of cached results.
$user = $db->get_row(null,OBJECT,1) ;
// Note: Row offset starts at 0
echo “$user->name joined us on ” . date(“m/d/y”,$user->date_joined);
Output:
Tyson joined us on 05/02/02
// Get one row as a numerical array..
$user = $db->get_row(“SELECT name,email,address FROM users WHERE id = 1”,ARRAY_N);
// Output the results as a table..
echo “<table>”;
for ( $i=1; $i <= count($user); $i++ )
{
echo “<tr><td>$i</td><td>$user[$I]</td></tr>”;
}
echo “</table>”;
Output:
1 amy
2 amy@foo.com
3 123 Foo Road
$db->get_results
$db->get_results – get multiple row result set from the database (or previously cached results)
Description
array $db->get_results(string query / null [, OBJECT / ARRAY_A / ARRAY_N ] )
$db->get_row() gets multiple rows of results from the database based on query and returns them as a multi dimensional array. Each element of the array contains one row of results and can be specified to be either an object, associative array or numerical array. If no results are found then the function returns false enabling you to use the function within logic statements such as if.
Returning results as an object is the quickest way to get and display results. It is also useful that you are able to put $object->var syntax directly inside print statements without having to worry about causing php parsing errors.
// Extract results into the array $users (and evaluate if there are any results at the same time)..
if ( $users = $db->get_results(“SELECT name, email FROM users”) )
{
// Loop through the resulting array on the index $users[n]
foreach ( $users as $user )
{
// Access data using column names as associative array keys
echo “$user->name - $user->email<br>”;
}
}
else
{
// If no users were found then if evaluates to false..
echo “No users found.”;
}
Output:
Amy - amy@hotmail.com
Tyson - tyson@hotmail.com
Returning results as an associative array is useful if you would like dynamic access to column names. Here is an example.
// Extract results into the array $dogs (and evaluate if there are any results at the same time)..
if ( $dogs = $db->get_results(“SELECT breed, owner, name FROM dogs”, ARRAY_A) )
{
// Loop through the resulting array on the index $dogs[n]
foreach ( $dogs as $dog_detail )
{
// Loop through the resulting array
foreach ( $dogs_detail as $key => $val )
{
// Access and format data using $key and $val pairs..
echo “<b>” . ucfirst($key) . “</b>: $val<br>”;
}
// Do a P between dogs..
echo “<p>”;
}
}
else
{
// If no users were found then if evaluates to false..
echo “No dogs found.”;
}
Output:
Breed: Boxer
Owner: Amy
Name: Tyson
Breed: Labrador
Owner: Lee
Name: Henry
Breed: Dachshund
Owner: Mary
Name: Jasmine
Returning results as a numerical array is useful if you are using completely dynamic queries with varying column
names but still need a way to get a handle on the results. Here is an example of this concept in use. Imagine that this
script was responding to a form with $type being submitted as either ‘fish’ or ‘dog’.
// Create an associative array for animal types..
$animal = array ( “fish” => “num_fins”, “dog” => “num_legs” );
// Create a dynamic query on the fly..
if ( $results = $db->(“SELECT $animal[$type] FROM $type”,ARRAY_N))
{
foreach ( $results as $result )
{
echo “$result[0]<br>”;
}
}
else
{
echo “No $animal\s!”;
}
Output:
4
4
4
Note: The dynamic query would be look like one of the following...
· SELECT num_fins FROM fish
· SELECT num_legs FROM dogs
It would be easy to see which it was by using $db->debug(); after the dynamic query call.
$db->debug
$db->debug – print last sql query and returned results (if any)
Description
$db->debug(void)
$db->debug() prints last sql query and its results (if any)
If you need to know what your last query was and what the returned results are here is how you do it.
// Extract results into the array $users..
$users = $db->get_results(“SELECT name, email FROM users”);
// See what just happened!
$db->debug();
$db->vardump
$db->vardump – print the contents and structure of any variable
Description
$db->vardump(void)
$db->vardump() prints the contents and structure of any variable. It does not matter what the structure is be it an object, associative array or numerical array.
If you need to know what value and structure any of your results variables are here is how you do it.
// Extract results into the array $users..
$users = $db->get_results(“SELECT name, email FROM users”);
// View the contents and structure of $users
$db->vardump($users);
$db->get_col
$db->get_col – get one column from query (or previously cached results) based on column offset
Description
$db->get_col( string query / null [, int column offset] )
$db->get_col() extracts one column as one dimensional array based on a column offset. If no offset is supplied the offset will defualt to column 0. I.E the first column. If a null query is supplied the previous query results are used.
// Extract list of products and print them out at the same time..
foreach ( $db->get_col(“SELECT product FROM product_list”) as $product)
{
echo $product;
}
// Extract results into the array $users..
$users = $db->get_results(“SELECT * FROM users”);
// Work out how many columns have been selected..
$last_col_num = $db->num_cols - 1;
// Print the last column of the query using cached results..
foreach ( $db->get_col(null, $last_col_num) as $last_col )
{
echo $last_col;
}
$db->get_col_info
$db->get_col_info - get information about one or all columns such as column name or type
Description
$db->get_col_info(string info-type[, int column offset])
$db->get_col_info()returns meta information about one or all columns such as column name or type. If no information type is supplied then the default information type of name is used. If no column offset is supplied then a one dimensional array is returned with the information type for ‘all columns’. For access to the full meta information for all columns you can use the cached variable $db->col_info
Available Info-Types
mySQL
ibase
MS-SQL / Oracle / Postgress
SQLite
// Extract results into the array $users..
$users = $db->get_results(“SELECT id, name, email FROM users”);
// Output the name for each column type
foreach ( $db->get_col_info(“name”) as $name )
{
echo “$name<br>”;
}
Output:
id
name
// Extract results into the array $users..
$users = $db->get_results(“SELECT id, name, email FROM users”);
// View all meta information for all columns..
$db->vardump($db->col_info);
$db->hide_errors
$db->hide_errors – turn ezSQL error output to browser off
Description
$db->hide_errors( void )
$db->hide_errors() stops error output from being printed to the web client. If you would like to stop error output but still be able to trap errors for debugging or for your own error output function you can make use of the global error array $EZSQL_ERROR.
Note: If there were no errors then the global error array $EZSQL_ERROR will evaluate to false. If there were one or more errors then it will have the following structure. Errors are added to the array in order of being called.
$EZSQL_ERROR[0] = Array
(
[query] => SOME BAD QUERY
[error_str] => You have an error in your SQL syntax near ‘SOME BAD QUERY' at line 1
)
$EZSQL_ERROR[1] = Array
(
[query] => ANOTHER BAD QUERY
[error_str] => You have an error in your SQL syntax near ‘ANOTHER BAD QUERY' at line 1
)
$EZSQL_ERROR[2] = Array
(
[query] => THIRD BAD QUERY
[error_str] => You have an error in your SQL syntax near ‘THIRD BAD QUERY' at line 1
)
// Using a custom error function
$db->hide_errors();
// Make a silly query that will produce an error
$db->query(“INSERT INTO my_table A BAD QUERY THAT GENERATES AN ERROR”);
// And another one, for good measure
$db->query(“ANOTHER BAD QUERY THAT GENERATES AN ERROR”);
// If the global error array exists at all then we know there was 1 or more ezSQL errors..
if ( $EZSQL_ERROR )
{
// View the errors
$db->vardump($EZSQL_ERROR);
}
else
{
echo “No Errors”;
}
$db->show_errors
$db->show_errors – turn ezSQL error output to browser on
Description
$db->show_errors( void )
$db->show_errors() turns ezSQL error output to the browser on. If you have not used the function $db->hide_errors this function (show_errors) will have no effect.
$db->escape
$db->escape – Format a string correctly in order to stop accidental mal formed queries under all PHP conditions.
Description
$db->escape( string )
$db->escape() makes any string safe to use as a value in a query under all PHP conditions. I.E. if magic quotes are turned on or off. Note: Should not be used by itself to guard against SQL injection attacks. The purpose of this function is to stop accidental mal formed queries.
// Escape and assign the value..
$title = $db->escape(“Justin’s and Amy’s Home Page”);
// Insert in to the DB..
$db->query(“INSERT INTO pages (title) VALUES (’$title’)”) ;
// Assign the value..
$title = “Justin’s and Amy’s Home Page”;
// Insert in to the DB and escape at the same time..
$db->query(“INSERT INTO pages (title) VALUES (’”. $db->escape($title).”’)”) ;