Difference between Amazon SimpleDB and PostgreSQL

1. PostgreSQL : PostgreSQL is a powerful, open-source Object-relational database system. It provides good performance with low maintenance efforts because of its high stability. PostgreSQL was the first DBMS that implemented multi-version concurrency control (MVCC) feature. 

2. Amazon SimpleDB : It is a hosted simple database service by Amazon, with the data stored in the Amazon Cloud. It is Amazon is a web service for running queries on structured data in real-time. This database is written in Erlang by Amazon.com. It has the following features – high availability and flexibility, with little or no administrative burden. 

Difference between PostgreSQL and Amazon SimpleDB :

S.No.	PostgreSQL	Amazon SimpleDB
1.	It is developed By PostgreSQL Global Development Group on 1989.	It is developed By Amazon in 2007.
2.	It is Open Source.	It is commercial.
3.	Server operating systems for PostgreSQL is FreeBSD, HP-UX, Linux, NetBSD, OpenBSD, OS X, Solaris, Unix, Windows.	Server operating systems for Amazon SimpleDB is hosted.
4.	Its Primary database model is a Relational DBMS.	Its primary database model is the Key-value store.
5.	It has predefined data type such as date or float.	It has  no predefined data type such as date or float.
6.	It supports SQL.	It does not support SQL.
7.	APIs and other access methods for PostgreSQL is ADO.NET, JDBC, native C library, ODBC, streaming API for large objects.	APIs and other access methods for Amazon SimpleDB is RESTful HTTP API.
8.	Programming languages supported by PostgreSQL are .Net, C, C++, Delphi, Java, JavaScript (Node.js), Perl, PHP, Python, Tcl.	Programming languages supported by Amazon SimpleDB are .Net, C, C++, Erlang, Java, PHP, Python, Ruby, Scala.
9.	It supports Server-side scripting using user defined functions.	It does not support Server-side scripting.
10.	It supports Triggers.	It does not support Triggers.
11.	It supports Partitioning methods using partitioning by range, list and (since PostgreSQL 11) by hash.	It does not support Partitioning methods.
12.	It provides the concept of Referential Integrity. Hence, there is Foreign Keys.	It does not provide the concept of Referential Integrity. Hence, there is no Foreign Keys.
13.	It supports ACID properties.	It does not support ACID properties.