PyOrient OGM - Connection

In order to use the Object-Graph Mapper with your application, you first need to connect to a running OrientDB Server. In PyOrient, there are two interface classes used in this process and you can access them through an import statement:

# Module Imports
from pyorient.ogm import Graph, Config

• pyorient.ogm.Graph Wraps the lower-level PyOrient Client, that is, pyorient.OrientDB() and adds to it support for mapping Python classes to OrientDB database schemas and database schemas to Python Classes.

• pyorient.ogm.Config Provides an interface for defining how the OGM connects to OrientDB.

Connecting to OrientDB

When the PyOrient OGM connects to OrientDB, it uses the pyorient.ogm.Config class to define the specific database and credentials it uses in establishing the connection.

Syntax

Config.from_url(
      <database-url>, 
      <user>, 
      <password>, 
      initial_drop = False)

• <database-url> Defines the database.
• <user> Defines the username.
• <password> Defines the user password.
• initial_drop Defines whether PyOrient should drop any existing databases that share this configuration.

For the database URL, you have the option of using one of several supported formats:

• Connecting to a PLocal database:
  • localhost/<database-name>
  • plocal://localhost:<port>/<database-name>
• Connecting to a Memory database:
  • <database-name>
  • memory://localhost:<port>/<database-name>

Example

For instance, say that you have a smart home system written in Python that uses OrientDB for back-end database storage. You might use something like this to set up the database connection for your application:

# Connect to Database
Config.from_url(
   'plocal://localhost:2424/smarthome',
   'root', 'root_passwd')

Connecting with Graph Object

In addition to basic connection described above, you can also pass the connection configuration when you initialize the Graph object. For instance,

graph = Graph(
      Config.from_url(
         'localhost/smarthome',
     'root', 'root_passwd'))

This initializes a graph instance of the pyorient.ogm.Graph class and defines how you want the OGM to connect to OrientDB. You can then use graph in your applications to access further PyOrient OGM methods.