Propel Your PHP Applications

Slide 1: Propel Your PHP Applications Hans Lellelid International PHP Conference 2007-11-06

Slide 2: Introduction • My name is Hans Lellelid • Developer + manager at Applied Security, Inc. (near Washington DC). • I wrote/ported original Propel. • I currently manage the project with David Zülke – and an ever-growing team of developers. Hans Lellelid: Propel Your PHP Applications 2

Slide 3: This Talk • Overview of Propel • A typical work cycle • More in-depth usage • Advanced features • Slides available at http://propel.phpdb.org/presentations/ Hans Lellelid: Propel Your PHP Applications 3

Slide 4: Pre-Flight Check Going over the basics. Hans Lellelid: Propel Your PHP Applications 4

Slide 5: Fact Sheet • Propel is an ORM tool for PHP5. – It is also a code (and DDL) generator. • Based on Apache Torque. • Includes runtime and generator frameworks. • Uses PDO (v1.2 uses Creole) • Generator uses Phing tasks to create the PHP and SQL files. • Installs using PEAR installer. Hans Lellelid: Propel Your PHP Applications 5

Slide 6: ORM Patterns in PHP • The most common alternative ORM pattern in PHP is ActiveRecord. – (Thank you, Ruby on Rails!) • Propel is not an ActiveRecord implementation: it is a Row Data Gateway + Table Data Gateway implementation. • Key differences: – Clean division of labor between table operation objects and row instances. – RDG and TDG are inherently simpler, more transparent, models. Hans Lellelid: Propel Your PHP Applications 6

Slide 7: Motivations & Purpose • Created because nothing comparable existed for PHP at the time. • Designed to facilitate prototyping and RAD • Basic Philosophy: Database tasks should feel as simple as they actually are. • Designed for “enterprise” frameworks. Hans Lellelid: Propel Your PHP Applications 7

Slide 8: Requirements • PHP 5 – Version 1.3 requires PHP >= 5.2 – SPL, PDO (1.3), XML, XSLT • Phing • A supported database. Currently Propel supports: MySQL, PostgreSQL, MSSQL, Oracle, SQLite Hans Lellelid: Propel Your PHP Applications 8

Slide 9: Propel will ... • Generate classes to represent your database (model) in an OOP way. – “Object” classes for rows (RDG) – “Peer” classes for table operations (TDG) • Build SQL (DDL) to initialize your database. • Use unit-of-work pattern to wrap nested inserts in transactions. • Provide Exception-based error handling. • Allow you to avoid SQL (if you want). • Type-cast output and escape input. Hans Lellelid: Propel Your PHP Applications 9

Slide 10: But Propel won't ... • Build forms, reports, or other display stuff. – Several full frameworks are built around Propel to provide this (e.g Symfony, Agavi) • Help you design your database. • Prevent you from writing insecure code. • Replenish essential electrolytes after a hard workout. Hans Lellelid: Propel Your PHP Applications 10

Slide 11: Flight Plan A Typical Propel Work Cycle Hans Lellelid: Propel Your PHP Applications 11

Slide 12: A Typical Workflow • Design Database in XML (schema.xml) • Configure generator (build.properties) • Configure runtime (runtime-conf.xml) • Build SQL DDL and PHP classes. • (Maybe) initialize database. • Use newly-built objects in your application. Hans Lellelid: Propel Your PHP Applications 12

Slide 13: schema.xml • The schema.xml is the single authority for your data model. • Written in [quite intuitive] XML <?xml version="1.0"?> <database name="demo"> <table name="session"> <column name="id" type="integer" primaryKey="true" /> <column name="name" type="varchar" size="255" /> <column name="room" type="varchar" size="16" /> <column name="speaker" type="varchar" size="32" /> </table> </database> • Will be validated by build process (DTD and schema provided). Hans Lellelid: Propel Your PHP Applications 13

Slide 14: build.properties • Generator uses “properties” files (Phing) • Propel needs to know (at least) your RDBMS and project name. • It's often simplest to start with the provided “bookstore” example. • Example minimal build.properties: propel.project = myproj propel.database = mysql propel.database.url = mysql:dbname=test Hans Lellelid: Propel Your PHP Applications 14

Slide 15: runtime-conf.xml • Runtime config expressed in XML. • Configures connection and (optionally) PEAR logging facility. • Gets converted to PHP by build process. <config> <propel> <datasources default="myproj"> <datasource id="myproj"> <adapter>mysql</adapter> <connection> <dsn>mysql:dbname=test</dsn> </connection> </datasource> </datasources> </propel> </config> Hans Lellelid: Propel Your PHP Applications 15

Slide 16: Build! • Run propel-gen /path/to/projdir to build the SQL DDL and PHP classes. • Watch output for errors. (They're red.) Hans Lellelid: Propel Your PHP Applications 16

Slide 17: Initialize DB • Use propel-gen /path/to/projdir insert-sql to run the generated DDL statements against your configured database. • This will delete any existing data! Hans Lellelid: Propel Your PHP Applications 17

Slide 18: Start using new OM • Initialize Propel require_once 'propel/Propel.php'; Propel::init('/path/to/myproj-conf.php'); • Configure your include_path to include the output directory. – Propel 1.3 uses SPL autoload. • Begin reading and writing DB rows with your new object model. Hans Lellelid: Propel Your PHP Applications 18

Slide 19: Cruising Altitude Getting comfortable with Propel. Hans Lellelid: Propel Your PHP Applications 19

Slide 20: Column Types • Propel uses an abstract subset of SQL types. • SQL types are mapped to specific PHP types. • You can override the SQL type for a column. • Temporal values (DATE, TIME, TIMESTAMP) will use PHP DateTime objects. Hans Lellelid: Propel Your PHP Applications 20

Slide 21: Expressing Relationships • Relationships between tables are defined using foreign keys. – Even for systems that don't support true FK constraints. • Propel supports single or composite foreign keys. • Support for deletion cascading emulation. • The related objects can be get/set just like simple column values. Hans Lellelid: Propel Your PHP Applications 21

Slide 22: Selecting Rows • retrieveByPK() static method exists to select a single row. • Criteria provides an OO approach to building queries. • Smart handling of column types. • Multiple “Criterion” objects can be grouped together to form complex queries. • You can also use SQL, if you prefer. Hans Lellelid: Propel Your PHP Applications 22

Slide 23: Customization • Build properties customize code generation. • Override method and constant naming from the schema.xml • Empty stub object & peer classes for custom methods: – New methods or – Override parent (base) methods Hans Lellelid: Propel Your PHP Applications 23

Slide 24: Over-Drive Wait ... I thought we were using airplane metaphors. Hans Lellelid: Propel Your PHP Applications 24

Slide 25: Locator Objects (LOBs) • LOB columns returned as PHP streams. – This is the PDO design (though there are some exceptions). • Mutator methods support streams or (string) file contents. Hans Lellelid: Propel Your PHP Applications 25

Slide 26: Inheritance • Propel supports table-per-class-hierarchy inheritance. • Subclasses can be enumerated in the schema.xml (faster) or resolved at runtime (more flexible). • Plans in place for other inheritance models. Hans Lellelid: Propel Your PHP Applications 26

Slide 27: Other Features • Reverse engineer existing databases (requires Creole) • Import and export data as XML • Generate Graphviz ERD from schema.xml • Represent trees in SQL using nested set approach. Hans Lellelid: Propel Your PHP Applications 27

Slide 28: Extension Paths • Integrating with other Phing projects • Custom platform classes – Affects generation of SQL DDL • Custom builder classes – Determine how your classes are built. Hans Lellelid: Propel Your PHP Applications 28

Slide 29: The 2.0 Horizon • Criteria redesign • New inheritance models • Eagerly awaiting PHP6 (or 5.3) – Namespaces – Late static binding • Plugin-based builder framework. Hans Lellelid: Propel Your PHP Applications 29

Slide 30: On Behalf of the Flight Crew ... Thanks for listening. :) Hans Lellelid: Propel Your PHP Applications 30