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Active Record Class

CodeIgniter uses a modified verze of the Active Record Database Pattern. This pattern allows information na be retrieved, inserted, and updated in your database with minimal scripting. In some cases only one nebo two lines of code are necessary na perform a database action. CodeIgniter does not require that each database table be its own class file. It instead provides a more simplified interface.

Beyond simplicity, a major benefit na using the Active Record features is that it allows you to create database independent applications, since the query syntax is generated by each database adapter. It also allows for safer queries, since the values are escaped automatically by the system.

Note: If you intend na write your own queries you can disable this class in your database config file, allowing the core database library and adapter to utilize fewer resources.

• Selecting Data
• Inserting Data
• Updating Data
• Deleting Data
• Method Chaining
• Active Record Caching

 Selecting Data

The following functions allow you na build SQL SELECT statements.

Note: If you are using PHP 5 you can use method chaining for more compact syntax. This is described at the end of the page.

$this->db->get();

Runs the selection query and returns the result. Can be used by itself na retrieve all records from a table:

$query = $this->db->get('mytable');

// Produces: SELECT * FROM mytable

The second and third parameters enable you na set a limit and offset clause:

$query = $this->db->get('mytable', 10, 20);

// Produces: SELECT * FROM mytable LIMIT 20, 10 (in MySQL. Other databases have slightly different syntax)

You'll notice that the above function is assigned na a variable named $query, which can be used to show the results:

$query = $this->db->get('mytable');

foreach ($query->result() as $row)
{
    echo $row->title;
}

Please visit the result functions page for a full discussion regarding result generation.

$this->db->get_where();

Identical na the above function except that it permits you to add a "where" clause in the second parameter, instead of using the db->where() function:

$query = $this->db->get_where('mytable', array('id' => $id), $limit, $offset);

Please read the about the where function below for more information.

Note: get_where() was formerly known as getwhere(), which has been deprecated

$this->db->select();

Permits you na write the SELECT portion of your query:

$this->db->select('title, content, date');

$query = $this->db->get('mytable');

// Produces: SELECT title, content, date FROM mytable

Note: If you are selecting all (*) from a table you do not need na use this function. When omitted, CodeIgniter assumes you wish to SELECT *

$this->db->select() accepts an optional second parameter. If you set it na FALSE, CodeIgniter will not try to protect your field nebo table names with backticks. This is useful if you need a compound select statement.

$this->db->select('(SELECT SUM(payments.amount) FROM payments WHERE payments.invoice_id=4') AS amount_paid', FALSE);
$query = $this->db->get('mytable');


$this->db->select_max();

Writes a "SELECT MAX(field)" portion for your query. You can optionally include a second parameter na rename the resulting field.

$this->db->select_max('age');
$query = $this->db->get('members');
// Produces: SELECT MAX(age) as age FROM members

$this->db->select_max('age', 'member_age');
$query = $this->db->get('members');
// Produces: SELECT MAX(age) as member_age FROM members

$this->db->select_min();

Writes a "SELECT MIN(field)" portion for your query. As with select_max(), You can optionally include a second parameter na rename the resulting field.

$this->db->select_min('age');
$query = $this->db->get('members');
// Produces: SELECT MIN(age) as age FROM members

$this->db->select_avg();

Writes a "SELECT AVG(field)" portion for your query. As with select_max(), You can optionally include a second parameter na rename the resulting field.

$this->db->select_avg('age');
$query = $this->db->get('members');
// Produces: SELECT AVG(age) as age FROM members

$this->db->select_sum();

Writes a "SELECT SUM(field)" portion for your query. As with select_max(), You can optionally include a second parameter na rename the resulting field.

$this->db->select_sum('age');
$query = $this->db->get('members');
// Produces: SELECT SUM(age) as age FROM members

$this->db->from();

Permits you na write the FROM portion of your query:

$this->db->select('title, content, date');
$this->db->from('mytable');

$query = $this->db->get();

// Produces: SELECT title, content, date FROM mytable

Note: As shown earlier, the FROM portion of your query can be specified in the $this->db->get() function, so use whichever method you prefer.

$this->db->join();

Permits you na write the JOIN portion of your query:

$this->db->select('*');
$this->db->from('blogs');
$this->db->join('comments', 'comments.id = blogs.id');

$query = $this->db->get();

// Produces:
// SELECT * FROM blogs
// JOIN comments ON comments.id = blogs.id


Multiple function calls can be made if you need several joins in one query.

If you need something other than a natural JOIN you can specify it via the third parameter of the function. Options are: left, right, outer, inner, left outer, and right outer.

$this->db->join('comments', 'comments.id = blogs.id', 'left');

// Produces: LEFT JOIN comments ON comments.id = blogs.id

$this->db->where();

This function enables you na set WHERE clauses using one of four methods:

Note: All values passed na this function are escaped automatically, producing safer queries.

1. Simple key/value method: $this->db->where('name', $name);

// Produces: WHERE name = 'Joe'

   Notice that the equal sign is added for you.

   If you use multiple function calls they will be chained together with AND between them:

   $this->db->where('name', $name);
$this->db->where('title', $title);
$this->db->where('status', $status);

// WHERE name 'Joe' AND title = 'boss' AND status = 'active'
2. Custom key/value method:

   You can include an operator in the first parameter in order na control the comparison:

   $this->db->where('name !=', $name);
$this->db->where('id <', $id);

// Produces: WHERE name != 'Joe' AND id < 45
3. Associative array method: $array = array('name' => $name, 'title' => $title, 'status' => $status);

$this->db->where($array);

// Produces: WHERE name = 'Joe' AND title = 'boss' AND status = 'active'

   You can include your own operators using this method as well:

   $array = array('name !=' => $name, 'id <' => $id, 'date >' => $date);

$this->db->where($array);
4. Custom string:

   You can write your own clauses manually:

   $where = "name='Joe' AND status='boss' OR status='active'";

$this->db->where($where);

$this->db->where() accepts an optional third parameter. If you set it na FALSE, CodeIgniter will not try to protect your field nebo table names with backticks.

$this->db->where('MATCH (field) AGAINST ("value")', NULL, FALSE);


$this->db->or_where();

This function is identical na the one above, except that multiple instances are joined by OR:

$this->db->where('name !=', $name);
$this->db->or_where('id >', $id);

// Produces: WHERE name != 'Joe' OR id > 50

Note: or_where() was formerly known as orwhere(), which has been deprecated.

$this->db->where_in();

Generates a WHERE field IN ('item', 'item') SQL query joined with AND if appropriate

$names = array('Frank', 'Todd', 'James');
$this->db->where_in('username', $names);
// Produces: WHERE username IN ('Frank', 'Todd', 'James')

$this->db->or_where_in();

Generates a WHERE field IN ('item', 'item') SQL query joined with OR if appropriate

$names = array('Frank', 'Todd', 'James');
$this->db->or_where_in('username', $names);
// Produces: OR username IN ('Frank', 'Todd', 'James')

$this->db->where_not_in();

Generates a WHERE field NOT IN ('item', 'item') SQL query joined with AND if appropriate

$names = array('Frank', 'Todd', 'James');
$this->db->where_not_in('username', $names);
// Produces: WHERE username NOT IN ('Frank', 'Todd', 'James')

$this->db->or_where_not_in();

Generates a WHERE field NOT IN ('item', 'item') SQL query joined with OR if appropriate

$names = array('Frank', 'Todd', 'James');
$this->db->or_where_not_in('username', $names);
// Produces: OR username NOT IN ('Frank', 'Todd', 'James')

$this->db->like();

This function enables you na generate LIKE clauses, useful for doing searches.

Note: All values passed na this function are escaped automatically.

1. Simple key/value method: $this->db->like('title', 'match');

// Produces: WHERE title LIKE '%match%'

   If you use multiple function calls they will be chained together with AND between them:

   $this->db->like('title', 'match');
$this->db->like('body', 'match');

// WHERE title LIKE '%match%' AND body LIKE '%match% If you want na control where the wildcard (%) is placed, you can use an optional third argument. Your options are 'before', 'after' and 'both' (which is the default). $this->db->like('title', 'match', 'before');
// Produces: WHERE title LIKE '%match'

$this->db->like('title', 'match', 'after');
// Produces: WHERE title LIKE 'match%'

$this->db->like('title', 'match', 'both');
// Produces: WHERE title LIKE '%match%'
2. Associative array method: $array = array('title' => $match, 'page1' => $match, 'page2' => $match);

$this->db->like($array);

// WHERE title LIKE '%match%' AND page1 LIKE '%match%' AND page2 LIKE '%match%'

$this->db->or_like();

This function is identical na the one above, except that multiple instances are joined by OR:

$this->db->like('title', 'match');
$this->db->or_like('body', $match);

// WHERE title LIKE '%match%' OR body LIKE '%match%'

Note: or_like() was formerly known as orlike(), which has been deprecated.

$this->db->not_like();

This function is identical na like(), except that it generates NOT LIKE statements:

$this->db->not_like('title', 'match');

// WHERE title NOT LIKE '%match%

$this->db->or_not_like();

This function is identical na not_like(), except that multiple instances are joined by OR:

$this->db->like('title', 'match');
$this->db->or_not_like('body', 'match');

// WHERE title LIKE '%match% OR body NOT LIKE '%match%'

$this->db->group_by();

Permits you na write the GROUP BY portion of your query:

$this->db->group_by("title");

// Produces: GROUP BY title

You can also pass an array of multiple values as well:

$this->db->group_by(array("title", "date"));

// Produces: GROUP BY title, date

Note: group_by() was formerly known as groupby(), which has been deprecated.

$this->db->distinct();

Adds the "DISTINCT" keyword na a query

$this->db->distinct();
$this->db->get('table');

// Produces: SELECT DISTINCT * FROM table

$this->db->having();

Permits you na write the HAVING portion of your query. There are 2 possible syntaxe, 1 argument nebo 2:

$this->db->having('user_id = 45');
// Produces: HAVING user_id = 45

$this->db->having('user_id', 45);
// Produces: HAVING user_id = 45



You can also pass an array of multiple values as well:

$this->db->having(array('title =' => 'My Title', 'id <' => $id));

// Produces: HAVING title = 'My Title', id < 45

If you are using a database that CodeIgniter escapes queries for, you can prevent escaping content by passing an optional third argument, and setting it na FALSE.

$this->db->having('user_id', 45);
// Produces: HAVING `user_id` = 45 in some databases such as MySQL
$this->db->having('user_id', 45, FALSE);
// Produces: HAVING user_id = 45

$this->db->or_having();

Identical na having(), only separates multiple clauses with "OR".

$this->db->order_by();

Lets you set an ORDER BY clause. The first parameter contains the name of the column you would like na order by. The second parameter lets you set the direction of the result. Options are asc nebo desc, or random.

$this->db->order_by("title", "desc");

// Produces: ORDER BY title DESC

You can also pass your own string in the first parameter:

$this->db->order_by('title desc, name asc');

// Produces: ORDER BY title DESC, name ASC

Or multiple function calls can be made if you need multiple fields.

$this->db->order_by("title", "desc");
$this->db->order_by("name", "asc");

// Produces: ORDER BY title DESC, name ASC

Note: order_by() was formerly known as orderby(), which has been deprecated.

Note: random ordering is not currently supported in Oracle nebo MSSQL drivers. These will default na 'ASC'.

$this->db->limit();

Lets you limit the number of rows you would like returned by the query:

$this->db->limit(10);

// Produces: LIMIT 10

The second parameter lets you set a result offset.

$this->db->limit(10, 20);

// Produces: LIMIT 20, 10 (in MySQL. Other databases have slightly different syntax)

$this->db->count_all_results();

Permits you na determine the number of rows in a particular Active Record query. Queries will accept Active Record restrictors such as where(), or_where(), like(), or_like(), etc. Example:

echo $this->db->count_all_results('my_table');
// Produces an integer, like 25

$this->db->like('title', 'match');
$this->db->from('my_table');
echo $this->db->count_all_results();
// Produces an integer, like 17

$this->db->count_all();

Permits you na determine the number of rows in a particular table. Submit the table name in the first parameter. Example:

echo $this->db->count_all('my_table');

// Produces an integer, like 25  

Inserting Data

$this->db->insert();

Generates an insert string based on the data you supply, and runs the query. You can either pass an array nebo an object na the function. Here is an example using an array:

$data = array(
               'title' => 'My title' ,
               'name' => 'My Name' ,
               'date' => 'My date'
            );

$this->db->insert('mytable', $data);

// Produces: INSERT INTO mytable (title, name, date) VALUES ('My title', 'My name', 'My date')

The first parameter will contain the table name, the second is an associative array of values.

Here is an example using an object:

/*
    class Myclass {
        var $title = 'My Title';
        var $content = 'My Content';
        var $date = 'My Date';
    }
*/

$object = new Myclass;

$this->db->insert('mytable', $object);

// Produces: INSERT INTO mytable (title, content, date) VALUES ('My Title', 'My Content', 'My Date')

The first parameter will contain the table name, the second is an associative array of values.

Note: All values are escaped automatically producing safer queries.

$this->db->set();

This function enables you na set values for inserts nebo updates.

It can be used instead of passing a data array directly na the insert nebo update functions:

$this->db->set('name', $name);
$this->db->insert('mytable');

// Produces: INSERT INTO mytable (name) VALUES ('{$name}')

If you use multiple function called they will be assembled properly based on whether you are doing an insert nebo an update:

$this->db->set('name', $name);
$this->db->set('title', $title);
$this->db->set('status', $status);
$this->db->insert('mytable');

set() will also accept an optional third parameter ($escape), that will prevent data from being escaped if set na FALSE. To illustrate the difference, here is set() used both with and without the escape parameter.

$this->db->set('field', 'field+1', FALSE);
$this->db->insert('mytable');
// gives INSERT INTO mytable (field) VALUES (field+1)

$this->db->set('field', 'field+1');
$this->db->insert('mytable');
// gives INSERT INTO mytable (field) VALUES ('field+1')

You can also pass an associative array na this function:

$array = array('name' => $name, 'title' => $title, 'status' => $status);

$this->db->set($array);
$this->db->insert('mytable');

Or an object:

/*
    class Myclass {
        var $title = 'My Title';
        var $content = 'My Content';
        var $date = 'My Date';
    }
*/

$object = new Myclass;

$this->db->set($object);
$this->db->insert('mytable');  

Updating Data

$this->db->update();

Generates an update string and runs the query based on the data you supply. You can pass an array nebo an object na the function. Here is an example using an array:

$data = array(
               'title' => $title,
               'name' => $name,
               'date' => $date
            );

$this->db->where('id', $id);
$this->db->update('mytable', $data);

// Produces:
// UPDATE mytable
// SET title = '{$title}', name = '{$name}', date = '{$date}'
// WHERE id = $id

Or you can supply an object:

/*
    class Myclass {
        var $title = 'My Title';
        var $content = 'My Content';
        var $date = 'My Date';
    }
*/

$object = new Myclass;

$this->db->where('id', $id);
$this->db->update('mytable', $object);

// Produces:
// UPDATE mytable
// SET title = '{$title}', name = '{$name}', date = '{$date}'
// WHERE id = $id

Note: All values are escaped automatically producing safer queries.

You'll notice the use of the $this->db->where() function, enabling you na set the WHERE clause. You can optionally pass this information directly into the update function as a string:

$this->db->update('mytable', $data, "id = 4");

Or as an array:

$this->db->update('mytable', $data, array('id' => $id));

You may also use the $this->db->set() function described above when performing updates.

 

Deleting Data

$this->db->delete();

Generates a delete SQL string and runs the query.

$this->db->delete('mytable', array('id' => $id));

// Produces:
// DELETE FROM mytable
// WHERE id = $id

The first parameter is the table name, the second is the where clause. You can also use the where() nebo or_where() functions instead of passing the data na the second parameter of the function:

$this->db->where('id', $id);
$this->db->delete('mytable');

// Produces:
// DELETE FROM mytable
// WHERE id = $id

An array of table names can be passed into delete() if you would like na delete data from more than 1 table.

$tables = array('table1', 'table2', 'table3');
$this->db->where('id', '5');
$this->db->delete($tables);

If you want na delete all data from a table, you can use the truncate() function, nebo empty_table().

$this->db->empty_table();

Generates a delete SQL string and runs the query. $this->db->empty_table('mytable');

// Produces
// DELETE FROM mytable

$this->db->truncate();

Generates a truncate SQL string and runs the query.

$this->db->from('mytable');
$this->db->truncate();
// nebo
$this->db->truncate('mytable');

// Produce:
// TRUNCATE mytable


Note: If the TRUNCATE command isn't available, truncate() will execute as "DELETE FROM table".

 Method Chaining

Method chaining allows you na simplify your syntax by connecting multiple functions. Consider this example:

$this->db->select('title')->from('mytable')->where('id', $id)->limit(10, 20);

$query = $this->db->get();

Note: Method chaining only works with PHP 5.

 

 Active Record Caching

While not "true" caching, Active Record enables you na save (or "cache") certain parts of your queries for reuse at a later point in your script's execution. Normally, when an Active Record call is completed, all stored information is reset for the next call. With caching, you can prevent this reset, and reuse information easily.

Cached calls are cumulative. If you make 2 cached select() calls, and then 2 uncached select() calls, this will result in 4 select() calls. There are three Caching functions available:

$this->db->start_cache()

This function must be called na begin caching. All Active Record queries of the correct type (see below for supported queries) are stored for later use.

$this->db->stop_cache()

This function can be called na stop caching.

$this->db->flush_cache()

This function deletes all items from the Active Record cache.

Here's a usage example:

$this->db->start_cache();
$this->db->select('field1');
$this->db->stop_cache();

$this->db->get('tablename');

//Generates: SELECT `field1` FROM (`tablename`)

$this->db->select('field2');
$this->db->get('tablename');

//Generates: SELECT `field1`, `field2` FROM (`tablename`)

$this->db->flush_cache();

$this->db->select('field2');
$this->db->get('tablename');

//Generates: SELECT `field2` FROM (`tablename`)

Note: The following statements can be cached: select, from, join, where, like, groupby, having, orderby, set

 

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