jsam 0.7

JSAM’s basic operations are get, put and remove, with basic support for transactions via begin, commit and rollback. All stored objects are identified by an integer key.

A JSAM database is opened by supplying a URL to jsam.jsurl.parse() and calling the open() method on the returned object. The syntax of URL depends on the particular “access method”.

The following URL types currently exist:

* file:   directory plain text JSON files
* rcs:    directory plain text JSON files under RCS
* cvs:    directory plain text JSON files under CVS (not tested)
* svn:    directory plain text JSON files under SVN (not tested)
* sqlite: object trees stored in an SQLite3 database
* mysql:  object trees stored in a MySQL database (lightly tested)
* pgsql:  object trees stored in a PostgreSQL database (lightly tested)

Query methods include:

* Collections: a jQuery/Django-like method-chained interface
* XPath query language subset (only supported for SQL backends)
* P4J (E4X-like) query language (only supported for SQL backends)
    which allows construction of "xpath" queries in Python using
    method chaining and operator overload, bridging the lexical divide
    between code and query.

pydoc jsam.<URLTYPE>_jsam

gives information on the URL syntax for <URLTYPE>

pydoc jsam.jsam.JSAM

gives information on jsam object methods

pydoc jsam.xpath

gives information on XPath query syntax (SQL backends only)

pydoc jsam.p4j

gives information on P4J Python native query syntax

NOTE:

* uses Python 2.6+ supplied "json"; requires "simplejson" on Python 2.5
* file-based storage depends on POSIX file semantics
* requires "MySQLdb" for MySQL
* requires "psycopg2" for PostgreSQL

The name “JSAM” is a joke on IBM Mainframe O/S data “Access Methods” (BDAM, BSAM, VSAM, ISAM, QSAM, BPAM).

The obvious name ‘jsonstore’ was already taken by another package in the Python Package Index (PyPI).

The URL/URI syntax was cribbed from Django, which copied SQLAlchemy.