#SQL

This is the most basic way to execute a query through a connection.

use Formal\AccessLayer\{
    Query\SQL,
    Row,
};

$query = SQL::of('SHOW TABLES');
$tables = $connection($query);
$tables->foreach(function(Row $row): void {
    echo $row->column('Tables_in_database_name')->match(
        static fn($name) => $name,
        static fn() => '',
    );
});

[!NOTE] if you replace the constructor ::of() by ::onDemand() it will run your query lazily by returning a lazy Sequence, meaning it won't keep the results in memory allowing you to handle very large results. This is particularly useful for SELECT queries.

#Parameters

For some queries you will need to specify parameters to provide values, you can bind them either by specifying their name or by an index

[!IMPORTANT] do not copy the values directly in the sql query as you'll be vulnerable to sql injection.

#Bound by name

This is useful when you use the same parameter multiple times in your query.

use Formal\AccessLayer\Query\Parameter;

$insert = SQL::of('INSERT INTO `users` (`username`, `name`) VALUES (:username, :username)');
$insert = $insert->with(Parameter::named('username', 'some username value'));
$connection($insert);

#Bound by index

This is the most simple approach as you only have to worry that you add the parameters in the order specified in the sql query.

use Formal\AccessLayer\Query\Parameter;

$insert = SQL::of('INSERT INTO `users` (`username`, `name`) VALUES (?, ?)');
$insert = $insert
    ->with(Parameter::of('some username value'))
    ->with(Parameter::of('some name'));
$connection($insert);

[!NOTE] traditionally the index value rely on the user (you) to be specified (see PDOStatement::bindValue), but this increase the probability for you to make an error. This problem is resolved here as the order in which the parameters are provided is always respected, this allows the connection to correctly provide the index to \PDO.