# Working with the supported foreign data wrappers for Amazon RDS for PostgreSQL
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A foreign data wrapper (FDW) is a specific type of extension that provides access to external data. For example, the `oracle_fdw` extension allows your RDS for PostgreSQL DB cluster to work with Oracle databases. As another example, by using the PostgreSQL native `postgres_fdw` extension you can access data stored in PostgreSQL DB instances external to your RDS for PostgreSQL DB instance.

Following, you can find information about several supported PostgreSQL foreign data wrappers. 

**Topics**
+ [Using the log\$1fdw extension to access the DB log using SQL](CHAP_PostgreSQL.Extensions.log_fdw.md)
+ [Using the postgres\$1fdw extension to access external data](postgresql-commondbatasks-fdw.md)
+ [Working with MySQL databases by using the mysql\$1fdw extension](postgresql-mysql-fdw.md)
+ [Working with Oracle databases by using the oracle\$1fdw extension](postgresql-oracle-fdw.md)
+ [Working with SQL Server databases by using the tds\$1fdw extension](postgresql-tds-fdw.md)