To submit a query, use the following function:
$this->db->query('YOUR QUERY HERE');
place raw SQL in the query() method
$query = $this->db->query("select * from users");
Pass query in a variable
$sql = "select * from users";
$query = $this->db->query($sql);
Use the built-in get() method
$query = $this-> db-> get('users');
Read & Write Query
- The query() function returns a database result object when "read" type queries are run, which you can use to show your results.
- When "write" type queries are run it simply returns TRUE or FALSE depending on success or failure.
- When retrieving data you will typically assign the query to your own variable, like this:
$query = $this->db->query('YOUR QUERY HERE');
- This is a simplified version of the $this->db->query() function.
- It ONLY returns TRUE/FALSE on success or failure.
- It DOES NOT return a database result set.
- It does it set the query timer, or compile bind data, or store your query for debugging.
- It simply lets you submit a query. Most users will rarely use this function.
Set Prefixes For Table
If you have configured a database prefix and would like to prepend it to a table name for use in a native SQL query for example, then you can use the following:
Set Dynamic Prefix For Table
If for any reason you would like to change the prefix programatically without needing to create a new connection, you can use this method:
In many databases it is advisable to protect table and field names - for example with backticks in MySQL. Active Record queries are automatically protected, however if you need to manually protect an identifier you can use:
This function will also add a table prefix to your table, assuming you have a prefix specified in your database config file. To enable the prefixing set TRUE (boolen) via the second parameter:
Escaping Queries (Security Practice)
It's a very good security practice to escape your data before submitting it into your database. CodeIgniter has three methods that help you do this:
This function determines the data type so that it can escape only string data. It also automatically adds single quotes around the data
so you don't have to:
$sql = "INSERT INTO table (title) VALUES(".$this->db->escape($title).")";
This function escapes the data passed to it, regardless of type. Most of the time you'll use the above function rather than this one
. Use the function like this:
$sql = "INSERT INTO table (title) VALUES('".$this->db->escape_str($title)."')";
This method should be used when strings are to be used in LIKE conditions
so that LIKE wildcards ('%', '_') in the string are also properly escaped.
$search = '20% raise';
$sql = "SELECT id FROM table WHERE column LIKE '%".$this->db->escape_like_str($search)."%'";
Bindings enable you to simplify your query syntax by letting the system put the queries together for you. Consider the following example:
$sql = "SELECT * FROM some_table WHERE id = ? AND status = ? AND author = ?";
$this->db->query($sql, array(3, 'live', 'Rick'));
The question marks in the query are automatically replaced with the values in the array in the second parameter of the query function.