FDO RFC 16 - FDO Provider for SQLite

This page contains a request for comments document (RFC) for the FDO Open Source project. More FDO RFCs can be found on the RFCs page.

Status

RFC Template Version	(1.0)
Submission Date
Last Modified	Traian Stanev 2008-03-18
Author	Traian Stanev
RFC Status	draft
Implementation Status	under development
Proposed Milestone
Assigned PSC guide(s)	(when determined)
Voting History	(vote date)
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Overview

This RFC proposes a new FDO provider for accessing (spatial) data stored in SQLite database files.

Motivation

SQLite is an efficient and popular way to store data. Support for accessing SQLite databases via FDO would expand the range of data sources supported by FDO.

Proposed Solution

The proposed SQLite provider will have the following features:

• Data stored and consumed in native SQLite format, and therefore accessible to other SQLite-based applications;
• Geometry will be serialized as BLOBs in FDO geometry format (FGF). Other ways that may be considered are storing points as X,Y columns and also geometry as WKB format;
• A non-persistent, spatial index usable for BBOX queries built on the fly and valid for the duration of the FDO connection;
• Execution of arbitrary SQL commands;
• A metadata table where the geometry coordinate system is stored in WKT or EPSG form. In addition, PRJ files will be supported as alternative means of specifying a coordinate system when a metadata table is undesirable;
• A tentative list of supported FDO commands : DescribeSchema, Select, SelectAggregates, Insert, Update, Delete, GetSpatialContexts, arbitrary SQL, ApplySchema, CreateDataStore;

FDO features the provider will likely *not* support:

• Feature class inheritance;
• Geometry filters other than BBOX;
• FDO Transactions -- but you can still manually execute BEGIN/COMMIT around other FDO commands;
• Associations;
• Constraints;
• Any other exotic feature you can think of.

Implications

This is a new provider, so there will be no issues with backwards compatibility.

Test Plan

There will be a small test suite that tests often used functionality. Arbitrary SQL execution will not be tested extensively.

Funding/Resources