Doctrine - PHP Data Persistence and ORM Tool GENERAL FEATURES Fully object-oriented following best practices and design patterns Multiple databases Database connection pooling with connection-record -registry Runtime configuration (no XML needed!) Very modular structure (only uses the needed features) The runtime components can be compiled into a single file Leveled configuration (attributes can be set at global, connection and table levels) DATABASE ABSTRACTION A DSN (data source name) or array format for specifying database servers Datatype abstraction and on demand datatype conversion supports PDO Database query profiling Query caching Sequence / autoincrement emulation Replace emulation RDBMS management methods (creating, dropping, altering) SQL function call abstraction SQL expression abstraction Pattern matching abstraction Portable error codes Nested transactions Transaction isolation abstraction Transaction savepoint abstraction Index/Unique Key/Primary Key support Ability to read the information schema Reverse engineering schemas from an existing database LIMIT / OFFSET emulation OBJECT RELATIONAL MAPPING General features Validators Transactional errorStack for easy retrieval of all errors EventListeners UnitOfWork pattern (easy saving of all pending objects) Uses ActiveRecord pattern State-wise records and transactions Importing existing database schemas to Doctrine ActiveRecord objects Exporting Doctrine ActiveRecords to database (= automatic table creation) Mapping Composite, Natural, Autoincremented and Sequential identifiers PHP Array / Object data types for columns (automatic serialization/unserialization) Gzip datatype for all databases Emulated enum datatype for all databases Datatype abstraction Column aggregation inheritance One-class-one-table inheritance as well as One-table One-to-many, many-to-one, one-to-one and many-to-many relations Self-referencing relations even for association table relations Relation aliases Object population DQL (Doctrine Query Language), an EJB 3 spec compliant OQL The limit-subquery-algorithm OO-style query API for both DQL and raw SQL Object population from database views Object population through raw SQL Transactions and locking Pessimistic offline locking Savepoints, transaction isolation levels and nested transactions Transactional query optimization (gathering of DELETE statements)