object-oriented database management system

object-oriented database management system

An object database (also object-oriented database management system) is a  database  management system in which information is represented in the form of  objects as used in  object- oriented programming. Object databases are different from  relational databases which are table-oriented.  Object-relational databases are a hybrid of both approaches.

Object-oriented database management systems (OODBMSs) combine database capabilities with  object-oriented programming language capabilities. OODBMSs allow object-oriented programmers to develop the product, store them as objects, and replicate or modify existing objects to make new objects within the OODBMS. Because the database is integrated with the programming language, the programmer can maintain consistency within one environment, in that both the OODBMS and the programming language will use the same model of representation. Relational DBMS projects, by way of contrast, maintain a clearer division between the database model and the application.

class Dbms()

Creates a Dbms object. Dbms objects support basic operations on a database.

Dbms objects have the following methods:

begin()

Begins a transaction on the database.

close()

Closes the database object. It is safe to try to close a database object even if it is not open.

commit()

Commits the current transaction.

compact()

Compacts the database, reclaiming unused space in the database file. create(dbname)

Creates a database with path dbname. execute(query)

Executes an SQL query. On success, returns 0 if a DDL (SQL schema update) statement was executed. Returns the number of rows inserted, updated, or deleted, if a DML (SQL data update) statement was executed.

open(dbname)

Opens the database in file dbname. This should be a full Unicode path name, for example, u'c:\\foo.db'.

rollback()

Rolls back the current transaction.