BAT::Session - session creation and retrieval

Back to top ^

NAME

BAT::Session - session creation and retrieval

Back to top ^

SYNOPSIS

  require BAT::Session;
  my $session_id = BAT::Session::new(%session_data);
  my $session_data = BAT::Session::session_data($session_id);

Back to top ^

DESCRIPTION

Sessions within BAT enable concurrent analysis operations to avoid producing corrupted results. A session in BAT is the combination of a data source (DiGIR provider and resource) and an analysis layer (or analysis grid). It is possible to run different types of analysis against the same session, although the current implementation of BAT creates a new session for each analysis. This effectively adds analysis type as a component of a session, although it is not stored with session data.

BAT::Session Stores and retrieves session data for BAT. The module relies on BAT::Database for creating session ids and storing sessions in between script invocations.

Back to top ^

FUNCTIONS

new()

  my $session_id = BAT::Session::new(%session_data);

Creates a new session, returning the new session id. new() accepts the following arguments in its session_data hash:

  data_source_id
  grid_size
  field_name
  field_value

data_source_id must correspond to an entry in the data_sources table. grid_size must exactly match an entry in the analysis_layers table with a link to the same data_sources record. field_name must be a valid taxon level, eg 'Class', 'Order', or 'Family'. field_value is the value for the given field_name. From these arguments a session is created. The data stored for a session is described with the session_data() function.

session_data()

  my $session_data = BAT::Session::session_data($session_id);

Retrieves a hashref containing data for the given session id. Session data returned includes:

  session_id
  region         - eg 'Australia'
  analysis_layer - eg 'AUSTRALIA_1_DEGREE_GRID'
  provider_url   - eg 'http://www.deh.gov.au:80/biodiversity/digir/www/DiGIR.php'
  resource_code  - eg 'ANIC'
  data_source_name - eg 'Insects - Australian National Insect Collection - ANIC'
  field_name     - eg 'Family'
  field_value    - eg 'Libellulidae'
  west           
  east  
  south
  north
  grid_cell_size - eg '1'
  grid_size      - eg '1 Degree'
  date_created   - eg '10:31:32 28-06-2005'

The analysis_layer is the spatial layer containing the grid of analysis units and their bounding boxes. west, east, south, and north are derived from a query of the analysis_layer. They describe the edges of the analysis layer's bounding box. grid_cell_size is a decimal value of the edge of an analysis unit, while grid_size is the text to display for the decimal value.

Back to top ^

SEE ALSO

BAT::Database

Back to top ^

AUTHOR

  Bryn Honeyman 2005

Back to top ^

 BAT::Session - session creation and retrieval