MulticornPostgreSQL外部数据源访问接口

Multicorn 是一个 PostgreSQL 9.1+ 的扩展模块，用于简化外部数据封装开发，允许开发者使用 Python 编程语言开发。

特性：

• Multicorn 允许你访问 PostgreSQL 数据库的任何数据源
• 你可以使用强大的SQL来查询数据
• 任何SQL工具都可以在这些数据源上重用

支持的数据源包括：

• oracle_fdw – connects to Oracle databases.
• mysql_fdw – connects to MySQL databases.
• tds_fdw – connects to Sybase and Microsoft SQL Server databases.
• odbc_fdw – connects to any ODBC source.
• couchdb_fdw – connects to CouchDB databases.
• redis_fdw – connects to Redis databases.
• twitter_fdw – fetches messages from Twitter.
• ldap_fdw – queries LDAP servers.
• file_fdw – access data files in the server’s file system and query them as tables.
• file_fixed_length_record_fdw – reads flat files with columns of fixed width.
• PGStrom – uses GPU devices to accelerate sequential scan on massive amount of records with complex qualifiers.
• s3_fdw – reads files located in Amazon S3.
• www_fdw – accesses web services as a data source.

示例代码：

create foreign table gmail (
    "Message-ID" character varying,
    "From" character varying,
    "Subject" character varying,
    "payload" character varying,
    "flags" character varying[],
    "To" character varying) server multicorn_imap options (
        host 'imap.gmail.com',
        port '465',
        payload_column 'payload',
        flags_column 'flags',
        ssl 'True',
        login 'mylogin',
        password 'mypassword'
);

select flags, "Subject", payload  from gmail where "From" like 'pgsql-%'
and "Subject" like '%Daily digest%' limit 2;