1. Overview
      1. What It Is
      2. Why I Would Want to Use It
      3. Known Issues
    2. Getting Started
      1. Fundamentals
        1. Design Patterns
        2. xPDO, the Class
          1. As Object and Relational Mapper
          2. As PDO Wrapper
          3. As Service Layer
          4. The xPDO Constructor
            1. Hydrating Fields
      2. Introduction to the xPDO Object Model
        1. Understanding xPDOCriteria and xPDOQuery
      3. Creating a Model With xPDO
        1. Defining a Schema
          1. Defining Relationships
          2. Defining the Database and Tables
            1. Upgrading Models to Schema Version 1.1
          3. More Examples of xPDO XML Schema Files
          4. Validation Rules in your Schema
        2. Generating the Model Code
          1. Domain Classes
          2. O-R Maps
          3. Table Classes
      4. Using Your xPDO Model
        1. Creating Objects
        2. Database Connections and xPDO
        3. Loading Packages
        4. Removing Objects
          1. removeCollection
        5. Retrieving Objects
          1. getCollectionGraph
        6. Setting Object Fields
        7. Working with Related Objects
    3. Extending Your xPDO Model
      1. Adding Business Logic to this CRUD
      2. Overriding Derived Behavior
        1. Using Custom Object Loaders
      3. Working With Transient Object Classes
    4. Advanced Features
      1. Caching
        1. Caching Tutorial - Basic Snippets
        2. Caching Tutorial - Lifetimes
      2. Object Validation
        1. xPDOForeignKeyConstraint
        2. xPDOMaxLengthValidationRule
        3. xPDOMaxValueValidationRule
        4. xPDOMinLengthValidationRule
        5. xPDOMinValueValidationRule
        6. xPDOObjectExistsValidationRule
        7. A New Page
    5. xPDO Development
      1. Testing
      2. Building
      3. Documentation and Tutorials
    6. Class Reference
      1. xPDO
        1. xPDO.addPackage
        2. xPDO.beginTransaction
        3. xPDO.commit
        4. xPDO.connect
        5. xPDO.fromJSON
        6. xPDO.getCollection
        7. xPDO.getCollectionGraph
        8. xPDO.getCount
        9. xPDO.getDebug
        10. xPDO.getFields
        11. xPDO.getIterator
        12. xPDO.getManager
        13. xPDO.getObject
        14. xPDO.getObjectGraph
        15. xPDO.getOption
        16. xPDO.getTableName
        17. xPDO.loadClass
        18. xPDO.log
        19. xPDO.newObject
        20. xPDO.newQuery
        21. xPDO.query
        22. xPDO.setDebug
        23. xPDO.setLogLevel
        24. xPDO.setLogTarget
        25. xPDO.setOption
        26. xPDO.toJSON
      2. xPDOCacheManager
        1. xPDOCacheManager.copyFile
        2. xPDOCacheManager.copyTree
        3. xPDOCacheManager.delete
        4. xPDOCacheManager.deleteTree
        5. xPDOCacheManager.endsWith
        6. xPDOCacheManager.escapeSingleQuotes
        7. xPDOCacheManager.get
        8. xPDOCacheManager.getCachePath
        9. xPDOCacheManager.getCacheProvider
        10. xPDOCacheManager.matches
        11. xPDOCacheManager.replace
        12. xPDOCacheManager.set
        13. xPDOCacheManager.writeFile
        14. xPDOCacheManager.writeTree
      3. xPDOGenerator
        1. xPDOGenerator.parseSchema
        2. xPDOGenerator.writeSchema
      4. xPDOManager
        1. xPDOManager.createObjectContainer
        2. xPDOManager.createSourceContainer
        3. xPDOManager.removeObjectContainer
        4. xPDOManager.removeSourceContainer
      5. xPDOObject
        1. Configuration Accessors
          1. getOption
          2. setOption
        2. Field Accessors
          1. fromArray
          2. fromJSON
          3. get
          4. set
          5. toArray
          6. toJSON
        3. Metadata Accessors
          1. getFieldName
          2. getFKClass
          3. getFKDefinition
          4. getPK
          5. getPKType
          6. getSelectColumns
        4. Persistence Methods
          1. remove
          2. save
        5. Related Object Accessors
          1. addMany
          2. addOne
          3. getMany
          4. getOne
        6. State Accessors
          1. isDirty
          2. isLazy
          3. isNew
        7. Static Object Loaders
          1. _loadCollectionInstance
          2. _loadInstance
          3. _loadRows
          4. load
          5. loadCollection
          6. loadCollectionGraph
          7. Using Custom Loader Classes
        8. Validation
          1. addValidationRule
          2. getValidator
          3. isValidated
          4. removeValidationRules
          5. validate
      6. xPDOQuery
        1. xPDOQuery.andCondition
        2. xPDOQuery.groupby
        3. xPDOQuery.innerJoin
        4. xPDOQuery.leftJoin
        5. xPDOQuery.limit
        6. xPDOQuery.orCondition
        7. xPDOQuery.rightJoin
        8. xPDOQuery.select
        9. xPDOQuery.setClassAlias
        10. xPDOQuery.sortby
        11. xPDOQuery.where
      7. xPDORevisionControl
      8. xPDOTransport
        1. xPDOTransport.install
        2. xPDOTransport.pack
        3. xPDOTransport.uninstall
      9. xPDOValidator
        1. xPDOValidator.addMessage
        2. xPDOValidator.getMessages
        3. xPDOValidator.hasMessages
        4. xPDOValidator.validate

Creating a Model With xPDO

Welcome to the MODX Documentation. It is an ongoing effort of the MODX community. If you would like to participate or if you notice any errors or missing content, please let us know.

Creating custom models to use xPDO with database tables is a pretty simple task in xPDO.

What is a Model?

About MVC
Broadly speaking, the model layer in any MVC framework refers to data (often from the database) and the code that interacts with it. MODx uses xPDO as an object-relational map, which represents the database data in code form.

A model is simply a representation of a database in code form. xPDO uses XML schema files to define database tables as XML objects. This is a similar approach used by other MVC frameworks, e.g. Symphony, which uses YAML files to define models.

After a model has been defined in XML, the XML is parsed and builds out "maps" and class files. The maps are PHP arrays that are parsed at runtime to tell xPDO information about the tables. The classes are actual PHP classes by which each instance represents a row in the specified table.

  1. Defining a Schema
    1. Defining the Database and Tables
      1. Upgrading Models to Schema Version 1.1
    2. Defining Relationships
    3. More Examples of xPDO XML Schema Files
  2. Generating the Model Code
    1. Domain Classes
    2. Table Classes
    3. O-R Maps

See Also