Tags as a key/value combination
$doc = [
'tags' => [
'name' => 'A440',
'highway' => 'secondary',
'oneway' => 'yes'
]
];
$db->poi->createIndex( [ 'tags.name' => 1 ] );
$db->poi->createIndex( [ 'tags.highway' => 1 ] );
$db->poi->createIndex( [ 'tags.oneway' => 1 ] );
// Road with name=Strand
$db->poi->find( [ 'tags.name' => 'Strand' ] );
// All roads
$db->poi->find( [ 'tags.highway' => [ '$exists' => 1 ] ] );
Lots of indexes are required
Index can not be used for %highway=*%
Easy to extract data from