Query Helper Methods

Information From Executing a Query

$this->db->insert_id()

The insert ID number when performing database inserts.

Catatan

If using the PDO driver with PostgreSQL, or using the Interbase driver, this function requires a $name parameter, which specifies the appropriate sequence to check for the insert id.

$this->db->affected_rows()

Displays the number of affected rows, when doing “write” type queries (insert, update, etc.).

Catatan

In MySQL “DELETE FROM TABLE” returns 0 affected rows. The database class has a small hack that allows it to return the correct number of affected rows. By default this hack is enabled but it can be turned off in the database driver file.

$this->db->last_query()

Returns the last query that was run (the query string, not the result). Example:

$str = $this->db->last_query();

// Produces:  SELECT * FROM sometable....

Catatan

Disabling the save_queries setting in your database configuration will render this function useless.

Information About Your Database

$this->db->count_all()

Permits you to 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

$this->db->platform()

Outputs the database platform you are running (MySQL, MS SQL, Postgres, etc...):

echo $this->db->platform();

$this->db->version()

Outputs the database version you are running:

echo $this->db->version();

Making Your Queries Easier

$this->db->insert_string()

This function simplifies the process of writing database inserts. It returns a correctly formatted SQL insert string. Example:

$data = array('name' => $name, 'email' => $email, 'url' => $url);

$str = $this->db->insert_string('table_name', $data);

The first parameter is the table name, the second is an associative array with the data to be inserted. The above example produces:

INSERT INTO table_name (name, email, url) VALUES ('Rick', 'rick@example.com', 'example.com')

Catatan

Values are automatically escaped, producing safer queries.

$this->db->update_string()

This function simplifies the process of writing database updates. It returns a correctly formatted SQL update string. Example:

$data = array('name' => $name, 'email' => $email, 'url' => $url);

$where = "author_id = 1 AND status = 'active'";

$str = $this->db->update_string('table_name', $data, $where);

The first parameter is the table name, the second is an associative array with the data to be updated, and the third parameter is the “where” clause. The above example produces:

UPDATE table_name SET name = 'Rick', email = 'rick@example.com', url = 'example.com' WHERE author_id = 1 AND status = 'active'

Catatan

Values are automatically escaped, producing safer queries.