SQLEngine

SQLEngine provides a method for loading SQLMethods from the filesystem

Methods are associated with a symbolic name by which they are invoked.

The goal of SQLEngine was to provide support for , work integrating Zope with the OpenACS, as such the default format supported by SQLEngine for filesystem SQL is OpenACS's query file xml syntax.

A second distinct goal of SQLEngine was to provide an abstraction to allow further work on changes to Zope's relational integration.

Why do i want to use it

If you want to keep your sql methods on the fs, either for source control or because they're generated from an external source.

Definitions

Sources

sources are locations where one or more resources files maybe found. Generally sources are either directories or jar files jars unimplemented.

Resources

Resources constitute files which contain sql statements. Resources may delimit sql statements in a variety of fashions, how a particular resource is handled is dependent on the config file within the SQLEngine product. The default handling is for xml resource files

Queries

Queries represent SQLMethods gathered from Resources. they have an associated name that is used for calling them.

Architecture

SQLEngine is divided under the hood into four parts. The SQLEngine itself a Zope object that provides managment interfaces for adding and removing sources/resources/queries and one interface for calling a query which takes a symbolic name for the query and args executes it and returns the results.

The other components are the Finder which searches the file system for files with given file extensions. The Loader extracts the raw query information from these files. The Builder takes this raw information and turns it into a QueryObject that gets stored with associated name in the SQLEngine.

The parts were designed to be interchangable, replacements for any of these components can be specified in the EngineConfig File.

Usage

Add a SQLEngine specifying a connection. Add a source, for the sake of example you can point it to the data directory of the SQLEngine distribution which contains some sample xml query files from the OpenACS. Load the source. The engine is now populated. It can be called via EngineName.execute(method_name, args)

Management

functionality is provided for reloading methods from the filesystem.

Futures

This is currently prealpha ware in the sense that it only serves my purpose of usage with openacs's xml syntax and does not provide alot of additonal capabilities beyond that. in either management or usage.

Author

Kapil Thangavelu License: GPL CVS: $Id: README,v 1.1 2001/09/28 05:00:56 ender Exp $