Firebird Foreign Data Wrapper for PostgreSQL

This is an experimental foreign data wrapper (FDW) to connect PostgreSQL to Firebird. It provides basic functionality, including both read (SELECT) and write (INSERT/UPDATE/DELETE) support.However it is still very much work-in-progress; USE AT YOUR OWN RISK.

firebird_fdw will work with PostgreSQL 9.3 or later (it was developed against the current development version) and in its current form will not work with pre-9.3 versions (although it should be simple enough to add read-only support for 9.2).

It was written for Firebird 2.5 and will probably work with Firebird 2.0 or later. It should work with earlier versions if the 'disable_pushdowns' option is set (see below).

Supported platforms

firebird_fdw was developed on Linux and OS X, and should run on any reasonably POSIX-compliant system.

Installation

Prerequisites:

Firebird client library (libfbclient) and API header file (ibase.h)

libfq, a slightly saner API wrapper for the Firebird C API; see: https://github.com/ibarwick/libfq

The Firebird include/library files often end up in non-standard locations; PG_CPPFLAGS and SHLIB_LINK can be used to provide the appropriate flags. For OS X they would look something like this:

export PG_CPPFLAGS="-I /Library/Frameworks/Firebird.framework/Versions/A/Headers/" export SHLIB_LINK="-L/Library/Frameworks/Firebird.framework/Versions/A/Libraries/"

firebird_fdw is installed as a PostgreSQL extension; it requires the pg_config binary for the target installation to be in the shell path.

The usual 'make && make install' should take care of the actual compilation.

Usage

NOTE: these options are provisional and may change

firebird_fdw accepts the following options:

'address': The Firebird server's address (default: localhost) 'database': The name of the database to connect to 'username': The username to connect as (not case-sensitive) 'password': The user's password (note that Firebird only recognizes the first 8 characters of a password) 'table_name': The Firebird table name (not case-sensitive). Cannot be used together with the 'query' option. 'query': A Firebird SQL statement producing a result set which can be treated like a table. Cannot be used together with the 'table_name' option. 'column_name': The Firebird column name (not case-sensitive). 'updatable': Boolean value indicating whether the foreign server as a whole, or an individual table, is updatable. Default is true. Note that table-level settings override server-level settings. 'disable_pushdowns': Turns off pushdowns of WHERE clause elements to Firebird. Increases stability at the expense of speed.

Note that while PostgreSQL allows a foreign table to be defined without any columns, firebird_fdw will raise an error as soon as any operations are carried out on it.

Example

Install the extension:

CREATE EXTENSION firebird_fdw; CREATE FOREIGN DATA WRAPPER firebird HANDLER firebird_fdw_handler VALIDATOR firebird_fdw_validator;

Create a foreign server with appropriate configuration:

CREATE SERVER firebird_server FOREIGN DATA WRAPPER firebird OPTIONS ( address 'localhost', database '/path/to/database' );

Create an appropriate user mapping:

CREATE USER MAPPING FOR CURRENT_USER SERVER firebird_server OPTIONS(username 'sysdba', password 'masterke');

Create a foreign table referencing the Firebird table_name 'fdw_test':

CREATE FOREIGN TABLE fb_test( id SMALLINT, val VARCHAR(2048) ) SERVER firebird_server OPTIONS( table_name 'fdw_test' );

As above, but with aliased column names:

CREATE FOREIGN TABLE fb_test_table( id SMALLINT OPTIONS (column_name 'test_id'), val VARCHAR(2048) OPTIONS (column_name 'test_val') ) SERVER firebird_server OPTIONS( table_name 'fdw_test' );

Create a foreign table as a Firebird query:

CREATE FOREIGN TABLE fb_test_query( id SMALLINT, val VARCHAR(2048) ) SERVER firebird_server OPTIONS( query 'SELECT id, val FROM fdw_test' );

Features

UPDATE and DELETE statements use Firebird's row identifier RDB$DB_KEY to operate on arbitrary rows

ANALYZE support

pushdown of some WHERE clause conditions to Firebird (including translation of built-in functions)

Limitations

Many; among the more egregious:

No Firebird transaction support

No explicit character set/encoding support

No support for some Firebird datatypes (BLOB, ARRAY)

TIMESTAMP/TIME: currently sub-second units will be truncated on insertion or update

No connection caching