add: 'lazy' method

[carloscarucce]

This method creates a generator that will fetch one row at a time from the data set.
This aims to reduce memory load during ResultSet interation while maintaining the simplicity of "fetchAll" when using it inside a loop.

Here is an example:

$rows = $yourQuery->lazy(PDO::FETCH_ASSOC);

foreach ($rows as $row) {
    echo $row['name'], ' - ', $row['age'];
}

Hope you find it useful

[sorinsarca]

Hi @carloscarucce

This should probably implemented using existing API:

• use IteratorAggregate on class ResultSet
• use existing fetch*() methods, like fetchAssoc()

class ResultSet implements \IteratorAggregate {
  // Rest of the class ...

  public function getIterator(): \Generator
  {
     const statement = $this->statement;
     try {
       while (false !== ($row = $statement->fetch())) {
         yield $row;
       }
     } finally {
       $statement->closeCursor();
     }
  }
}

And can be directly used by foreach:

$result = $db->from('users')
             ->select(['name', 'email'])
             ->fetchAssoc();

foreach ($result as $user) {
  echo $user['name'], $user['email'], "\n";
}

[carloscarucce]

Hey @sorinsarca, hope you're doing well

That would make every result set iterate over a lazy source. Which would not be the optimal in some cases (where people invoke fetchAll, for instance).

Making it a separate method gives the user the control over the component so it is used only when it's needed.

[sorinsarca]

no, by implementing IteratorAggregate doesn't mean we get rid of the other methods like all() or first().