ezSQL abstraction library

MAWI uses ezSQL as MySQL abstraction library. This page is a restyling version of the ezSQL original info and examples, created by Justin Vincent, author of ezsql library.

Although MAWI has not been tested with other databases, in theory it will be possible to use PostgreSQL, Microsoft SQL, Oracle, SAP Sybase and CUBRID databases, using the ezsql connectors. Plese note that we actually do not support other than MySQL or MariaDB databases.

MAWI does not work without ezSQL, but you can use PDO or MySQLi in your own code, MAWI can create instances to PDO or MySQLi modifying a switch in configuration options.

We have tested ezSQL with the three PHP MySQL connectors supported, mysql, mysqli and pdo and it is working properly with any of them, but apparently mysql old functions are faster and mysqli slowest.



ezSQL library documentation index



 
  • ezSQL Overview

  • 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.

 

Quick Examples

Note: In all these examples no other code is required other than including ez_sql.php
Example 1

// Select multiple records from the database and print them out
$users = $db->get_results("SELECT name, email FROM users");

foreach ( $users as $user ){
    echo $user->name;
    echo $user->email;
}



Example 2

// 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;



Example 3

// Get one variable from the database and print it out..
$var = $db->get_var("SELECT count(*) FROM users");

echo $var;



Example 4

// Insert into the database
$db->query("INSERT INTO users (id, name, email) VALUES (NULL,'justin','jv@foo.com')");



Example 5

// Update the database
$db->query("UPDATE users SET name = 'Justin' WHERE id = 2)");



Example 6

// Display last query and all associated results
$db->debug();



Example 7

// Display the structure and contents of any result(s) .. or any variable
$results = $db->get_results("SELECT name, email FROM users");

$db->vardump($results);



Example 8

// 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;
}



Example 9

// Same as above ‘but quicker’
foreach ( $db->get_col("SELECT name,email FROM users",0) as $name ){
    echo $name;
}



Example 10

// 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();


 
  • Introduction

  • 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.


 

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->cache_dir //Path to mySQL caching dir.
$db->cache_queries //Boolean flag (see mysql/disk_cache_example.php)
$db->cache_inserts //Boolean flag (see mysql/disk_cache_example.php)
$db->use_disk_cache //Boolean flag (see mysql/disk_cache_example.php)
$db->cache_timeout //Number in hours (see mysql/disk_cache_example.php)


 

ezSQL functions explained

$db = new db

$db = new db -- Initiate new db object. Connect to a database server. Select a database.

Description

$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.

Example

// 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.
Example

// 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
Example 1

// Insert a new user into the database
$db->query("INSERT INTO users (id,name) VALUES (1,’Amy’)") 


Example 2

// Update user into the database
$db->query("UPDATE users SET name = ‘Tyson’ WHERE id = 1") ;          


Example 3

// 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.
Example 1

// Get total number of users from the database..
$num_users = $db->get_var("SELECT count(*) FROM users") ;


Example 2

// 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;


Example 3

// 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.";

}


Example 4

// 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.
Example 1

// 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
 */


Example 2

// 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
 */


Example 3

// Get second row of cached results.
$user = $db->get_row(null,OBJECT,1) ;

// Note: Row offset starts at 
echo "$user->name joined us on " . date("m/d/y",$user->date_joined);
 
/*
******
Output
******
Tyson joined us on 05/02/02
 */


Example 4

// 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.
Example 1 – Return results as objects (default)

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
"; } }else{ // If no users were found then if evaluates to false.. echo "No users found."; } /* ****** Output ****** Amy - amy@hotmail.com Tyson - tyson@hotmail.com */

Example 2 – Return results as associative array

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
 */


Example 3 – Return results as numerical array

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)
Example

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.
Example

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.
Example 1

// 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;
}

Example 2 – Working with cached results

// 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

  • name - column name
  • table - name of the table the column belongs to
  • max_length - maximum length of the column
  • not_null - 1 if the column cannot be NULL
  • primary_key - 1 if the column is a primary key
  • unique_key - 1 if the column is a unique key
  • multiple_key - 1 if the column is a non-unique key
  • numeric - 1 if the column is numeric
  • blob - 1 if the column is a BLOB
  • type - the type of the column
  • unsigned - 1 if the column is unsigned
  • zerofill - 1 if the column is zero-filled

ibase

  • name - column name
  • type - the type of the column
  • length - size of column
  • alias - undocumented
  • relation - undocumented

MS-SQL / Oracle / Postgress

  • name - column name
  • type - the type of the column
  • length - size of column

SQLite

  • name - column name
Example 1

// 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
email
 */


Example 2

// 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
)



Example
        
 // 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.
Example 1
        
// 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’)") ;
        
        

Example 2
        
// 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)."’)") ;