The foreign data wrapper is responsible for fetching data from the remote data source and returning it to the PostgreSQL executor. If wrapper must support in updating foreign tables. In this post, I'll demonstrate, how you may connect PostgreSQL database to Oracle database using oracle_fdw . Before going ahead kindly ensure that PostgreSQL is installed in your system . Let’s begin: Step-1 Software’s used in demo - Windows, PostgreSQL 9.5, 9.6 instantclient-basic-win-x86-64-11.2.0.1.0 instantclient-jdbc-win-x86-64-11.2.0.1.0 instantclient-odbc-win-x86-64-11.2.0.1.0 instantclient-sqlplus-win-x86-64-11.2.0.1.0 & Oracle_FDW as per version ( http://www.oracle.com/technetwork/topics/linuxx86-64soft-092277.html , https://pgxn.org/dist/oracle_fdw/ or version wise) Download all the files mentioned above, in a single folder and unzip entire files to this single folder. Suppose, we create a folder Oracle in c: drive ...