ppf.jabref

ppf.jabref provides a python interface to JabRef SQL databases. It maps database relations to python classes using SQLAlchemy. Also, ppf.jabref provides tools to parse the data stored inside the database tables.

JabRef's Database Layout

A JabRef database has these tables:

• ENTRY holds an ID, the entry type (e.g. 'book', or 'article'), and a version number
• FIELD uses the same entry as a foreign key, and lists all the fields in the entries row by row as key-value pairs.
• METADATA holds data about your library such as the base path of your document folder and the definitions of your filter groups.

The "file" field is a text describing which files are linked the the present entry. Note that all linked files are listed in a single row in the DB. The links are separated by ';' inside the text. Also, each link has multiple properties: name, path, and filetype. In the following example, entry_shared_id 2 has a single link with name='', path='a.pdf', filetype='PDF'.

Using ppf.jabref

ppf.jabref relies on SQLAlchemy for database access. All that ppf.jabref adds to this is a data model which makes sqlalchemy understand how a JabRef database is structured (by providing classes Entry and Field).

A simple example that queries all entries and prints a selection of the fields looks like this:

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from ppf.jabref import Entry, File

engine = create_engine('<your connection string here>', echo=False)
Session = sessionmaker(bind=engine)
session = Session()

q = session.query(Entry)
for entry in q:
    print(entry.fields['author'], '\t',
        entry.fields['title'], '\t',
        entry.fields['year'], '\t', end='')

    files = File.from_string(entry.fields['file'])
    for i in range(len(files)):
        f = files[i]
        print(f.path, '\t', end='')

The first 6 lines are setup code to import required packages and to set up the database connection. The query then uses ppf.jabref's Entry class to obtain all Entries (=references) in the JabRef database. The for-loop shows how to access fields and uses the File class to find out where the documents linked to this entry are stored.