PostgreSQL – object-relational database system

PostgreSQL is an object-relational database management system (ORDBMS) based on POSTGRES, Version 4.2, developed at the University of California at Berkeley Computer Science Department.

It has more than 30 years of active development and a proven architecture that has earned it a strong reputation for reliability, data integrity, and correctness. It is the most feature-rich robust open-source database.

PostgreSQL runs stored procedures in more than a dozen programming languages, including Java, Perl, Python, Ruby, Tcl, C/C++, and its own PL/pgSQL, which is similar to Oracle’s PL/SQL.

There are active PostgreSQL systems in production environments that manage in excess of 4 terabytes of data.

It supports a large part of the SQL standard and offers many modern features:

• Sophisticated query planner/optimizer.
• Fully ACID compliant.
• ANSI SQL compliant – Support for UNION, UNION ALL and EXCEPT queries.
• Referential Integrity.
• Transactional integrity.
• Replication (non-commercial and commercial solutions) allowing the duplication of the master database to multiple slave machines.
• Native interfaces for ODBC, JDBC, .Net, C, C++, PHP, Perl, TCL, ECPG, Python, and Ruby.
• Rules – allow the “query tree” of an incoming query to be rewritten.
• Views.
• Triggers – events triggered by the action of SQL query.
• Sequences.
• Inheritance.
• Outer Joins.
• Sub-selects.
• An open API.
• Stored Procedures.
• Native SSL support.
• Procedural languages.
• Hot stand-by (commercial solutions).
• Better than row-level locking.
• Functional and Partial indexes.
• Native Kerberos authentication.
• Loadable extensions offering SHA1, MD5, XML, and other functionality.
• Tools for generating portable SQL to share with other SQL-compliant systems.
• Extensible data type system providing for custom, user-defined datatypes and rapid development of new datatypes.
• Cross-database compatibility functions for easing the transition from other, less SQL-compliant RDBMS.
• Foreign keys.
• Multi-Version Concurrency Control (MVCC) which gives each user a “snapshot” of the database.
• Point in time recovery.
• Tablespaces.
• Asynchronous replication.
• Nested transactions (savepoints).
• Online/hot backups.
• Write ahead logging for fault tolerance.
• Supports international character sets, multibyte character encodings, Unicode, and it is locale-aware for sorting, case-sensitivity, and formatting.
• Highly scalable both in the sheer quantity of data it can manage and in the number of concurrent users it can accommodate.
• Streaming replication.
• In-place upgrades.
• Easy mass permissions management.
• Anonymous blocks and named parameter calls for stored procedures.
• New windowing functions and ordered aggregates.

Website: www.postgresql.org
Support: Documentation
Developer: PostgreSQL Global Development Group
License: BSD license

PostgreSQL is written in C. Learn C with our recommended free books and free tutorials.

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