(PECL mongo >=0.9.0)
Represents a MongoDB collection.
Collection names can use any character in the ASCII set. Some valid collection names are "", "...", "my collection", and "*&#@".
User-defined collection names cannot contain the $ symbol. There are certain system collections which use a $ in their names (e.g., local.oplog.$main), but it is a reserved character. If you attempt to create and use a collection with a $ in the name, MongoDB will assert.
$query
   [, array $update
   [, array $fields
   [, array $options
  ]]] ) : array$query = array()
   [, array $fields = array()
   [, array $options = array()
  ]]] ) : arrayMongoCollection::ASCENDINGMongoCollection::DESCENDINGThe "parent" database for this collection.
       The number of servers to replicate a change to before returning success.
       Value is inherited from the parent database. The 
       MongoDB class has a more detailed description of
       how w works.
      
       The number of milliseconds to wait for $this->w 
       replications to take place.  Value is inherited from the parent database.
       The MongoDB class has a more detailed description 
       of how wtimeout works.
      
MongoDB core docs on » collections.