Zend_Db_Table_Row

Introduction

Zend_Db_Table_Row is a class that contains an individual row of a Zend_Db_Table object. When you run a query against a Table class, the result is returned in a set of Zend_Db_Table_Row objects. You can also use this object to create new rows and add them to the database table.

Zend_Db_Table_Row is an implementation of the » Row Data Gateway pattern.

Fetching a Row

Zend_Db_Table_Abstract provides methods find() and fetchAll(), which each return an object of type Zend_Db_Table_Rowset, and the method fetchRow(), which returns an object of type Zend_Db_Table_Row.

Example #1 Example of fetching a row

  1. $bugs = new Bugs();
  2. $row = $bugs->fetchRow($bugs->select()->where('bug_id = ?', 1));

A Zend_Db_Table_Rowset object contains a collection of Zend_Db_Table_Row objects. See the chapter about table rowset for details.

Example #2 Example of reading a row in a rowset

  1. $bugs = new Bugs();
  2. $rowset = $bugs->fetchAll($bugs->select()->where('bug_status = ?', 1));
  3. $row = $rowset->current();

Reading column values from a row

Zend_Db_Table_Row_Abstract provides accessor methods so you can reference columns in the row as object properties.

Example #3 Example of reading a column in a row

  1. $bugs = new Bugs();
  2. $row = $bugs->fetchRow($bugs->select()->where('bug_id = ?', 1));
  3.  
  4. // Echo the value of the bug_description column
  5. echo $row->bug_description;

Note: Earlier versions of Zend_Db_Table_Row mapped these column accessors to the database column names using a string transformation called inflection.
Currently, Zend_Db_Table_Row does not implement inflection. Accessed property names need to match the spelling of the column names as they appear in your database.

Retrieving Row Data as an Array

You can access the row's data as an array using the toArray() method of the Row object. This returns an associative array of the column names to the column values.

Example #4 Example of using the toArray() method

  1. $bugs = new Bugs();
  2. $row = $bugs->fetchRow($bugs->select()->where('bug_id = ?', 1));
  3.  
  4. // Get the column/value associative array from the Row object
  5. $rowArray = $row->toArray();
  6.  
  7. // Now use it as a normal array
  8. foreach ($rowArray as $column => $value) {
  9.     echo "Column: $column\n";
  10.     echo "Value:  $value\n";
  11. }

The array returned from toArray() is not updateable. You can modify values in the array as you can with any array, but you cannot save changes to this array to the database directly.

Fetching data from related tables

The Zend_Db_Table_Row_Abstract class provides methods for fetching rows and rowsets from related tables. See the relationship chapter for more information on table relationships.

Writing rows to the database

Changing column values in a row

You can set individual column values using column accessors, similar to how the columns are read as object properties in the example above.

Using a column accessor to set a value changes the column value of the row object in your application, but it does not commit the change to the database yet. You can do that with the save() method.

Example #5 Example of changing a column in a row

  1. $bugs = new Bugs();
  2. $row = $bugs->fetchRow($bugs->select()->where('bug_id = ?', 1));
  3.  
  4. // Change the value of one or more columns
  5. $row->bug_status = 'FIXED';
  6.  
  7. // UPDATE the row in the database with new values
  8. $row->save();

Inserting a new row

You can create a new row for a given table with the createRow() method of the table class. You can access fields of this row with the object-oriented interface, but the row is not stored in the database until you call the save() method.

Example #6 Example of creating a new row for a table

  1. $bugs = new Bugs();
  2. $newRow = $bugs->createRow();
  3.  
  4. // Set column values as appropriate for your application
  5. $newRow->bug_description = '...description...';
  6. $newRow->bug_status = 'NEW';
  7.  
  8. // INSERT the new row to the database
  9. $newRow->save();

The optional argument to the createRow() method is an associative array, with which you can populate fields of the new row.

Example #7 Example of populating a new row for a table

  1. $data = array(
  2.     'bug_description' => '...description...',
  3.     'bug_status'      => 'NEW'
  4. );
  5.  
  6. $bugs = new Bugs();
  7. $newRow = $bugs->createRow($data);
  8.  
  9. // INSERT the new row to the database
  10. $newRow->save();

Note: The createRow() method was called fetchNew() in earlier releases of Zend_Db_Table. You are encouraged to use the new method name, even though the old name continues to work for the sake of backward compatibility.

Changing values in multiple columns

Zend_Db_Table_Row_Abstract provides the setFromArray() method to enable you to set several columns in a single row at once, specified in an associative array that maps the column names to values. You may find this method convenient for setting values both for new rows and for rows you need to update.

Example #8 Example of using setFromArray() to set values in a new Row

  1. $bugs = new Bugs();
  2. $newRow = $bugs->createRow();
  3.  
  4. // Data are arranged in an associative array
  5. $data = array(
  6.     'bug_description' => '...description...',
  7.     'bug_status'      => 'NEW'
  8. );
  9.  
  10. // Set all the column values at once
  11. $newRow->setFromArray($data);
  12.  
  13. // INSERT the new row to the database
  14. $newRow->save();

Deleting a row

You can call the delete() method on a Row object. This deletes rows in the database matching the primary key in the Row object.

Example #9 Example of deleting a row

  1. $bugs = new Bugs();
  2. $row = $bugs->fetchRow('bug_id = 1');
  3.  
  4. // DELETE this row
  5. $row->delete();

You do not have to call save() to apply the delete; it is executed against the database immediately.

Serializing and unserializing rows

It is often convenient to save the contents of a database row to be used later. Serialization is the name for the operation that converts an object into a form that is easy to save in offline storage (for example, a file). Objects of type Zend_Db_Table_Row_Abstract are serializable.

Serializing a Row

Simply use PHP's serialize() function to create a string containing a byte-stream representation of the Row object argument.

Example #10 Example of serializing a row

  1. $bugs = new Bugs();
  2. $row = $bugs->fetchRow('bug_id = 1');
  3.  
  4. // Convert object to serialized form
  5. $serializedRow = serialize($row);
  6.  
  7. // Now you can write $serializedRow to a file, etc.

Unserializing Row Data

Use PHP's unserialize() function to restore a string containing a byte-stream representation of an object. The function returns the original object.

Note that the Row object returned is in a disconnected state. You can read the Row object and its properties, but you cannot change values in the Row or execute other methods that require a database connection (for example, queries against related tables).

Example #11 Example of unserializing a serialized row

  1. $rowClone = unserialize($serializedRow);
  2.  
  3. // Now you can use object properties, but read-only
  4. echo $rowClone->bug_description;

Note: Why do Rows unserialize in a disconnected state?
A serialized object is a string that is readable to anyone who possesses it. It could be a security risk to store parameters such as database account and password in plain, unencrypted text in the serialized string. You would not want to store such data to a text file that is not protected, or send it in an email or other medium that is easily read by potential attackers. The reader of the serialized object should not be able to use it to gain access to your database without knowing valid credentials.

Reactivating a Row as Live Data

You can reactivate a disconnected Row, using the setTable() method. The argument to this method is a valid object of type Zend_Db_Table_Abstract, which you create. Creating a Table object requires a live connection to the database, so by reassociating the Table with the Row, the Row gains access to the database. Subsequently, you can change values in the Row object and save the changes to the database.

Example #12 Example of reactivating a row

  1. $rowClone = unserialize($serializedRow);
  2.  
  3. $bugs = new Bugs();
  4.  
  5. // Reconnect the row to a table, and
  6. // thus to a live database connection
  7. $rowClone->setTable($bugs);
  8.  
  9. // Now you can make changes to the row and save them
  10. $rowClone->bug_status = 'FIXED';
  11. $rowClone->save();

Extending the Row class

Zend_Db_Table_Row is the default concrete class that extends Zend_Db_Table_Row_Abstract. You can define your own concrete class for instances of Row by extending Zend_Db_Table_Row_Abstract. To use your new Row class to store results of Table queries, specify the custom Row class by name either in the $_rowClass protected member of a Table class, or in the array argument of the constructor of a Table object.

Example #13 Specifying a custom Row class

  1. class MyRow extends Zend_Db_Table_Row_Abstract
  2. {
  3.     // ...customizations
  4. }
  5.  
  6. // Specify a custom Row to be used by default
  7. // in all instances of a Table class.
  8. class Products extends Zend_Db_Table_Abstract
  9. {
  10.     protected $_name = 'products';
  11.     protected $_rowClass = 'MyRow';
  12. }
  13.  
  14. // Or specify a custom Row to be used in one
  15. // instance of a Table class.
  16. $bugs = new Bugs(array('rowClass' => 'MyRow'));

Row initialization

If application-specific logic needs to be initialized when a row is constructed, you can select to move your tasks to the init() method, which is called after all row metadata has been processed. This is recommended over the __construct() method if you do not need to alter the metadata in any programmatic way.

Example #14 Example usage of init() method

  1. class MyApplicationRow extends Zend_Db_Table_Row_Abstract
  2. {
  3.     protected $_role;
  4.  
  5.     public function init()
  6.     {
  7.         $this->_role = new MyRoleClass();
  8.     }
  9. }

Defining Custom Logic for Insert, Update, and Delete in Zend_Db_Table_Row

The Row class calls protected methods _insert(), _update(), and _delete() before performing the corresponding operations INSERT, UPDATE, and DELETE. You can add logic to these methods in your custom Row subclass.

If you need to do custom logic in a specific table, and the custom logic must occur for every operation on that table, it may make more sense to implement your custom code in the insert(), update() and delete() methods of your Table class. However, sometimes it may be necessary to do custom logic in the Row class.

Below are some example cases where it might make sense to implement custom logic in a Row class instead of in the Table class:

Example #15 Example of custom logic in a Row class

The custom logic may not apply in all cases of operations on the respective Table. You can provide custom logic on demand by implementing it in a Row class and creating an instance of the Table class with that custom Row class specified. Otherwise, the Table uses the default Row class.

You need data operations on this table to record the operation to a Zend_Log object, but only if the application configuration has enabled this behavior.

  1. class MyLoggingRow extends Zend_Db_Table_Row_Abstract
  2. {
  3.     protected function _insert()
  4.     {
  5.         $log = Zend_Registry::get('database_log');
  6.         $log->info(Zend_Debug::dump($this->_data,
  7.                                     "INSERT: $this->_tableClass",
  8.                                     false)
  9.                   );
  10.     }
  11. }
  12.  
  13. // $loggingEnabled is an example property that depends
  14. // on your application configuration
  15. if ($loggingEnabled) {
  16.     $bugs = new Bugs(array('rowClass' => 'MyLoggingRow'));
  17. } else {
  18.     $bugs = new Bugs();
  19. }

Example #16 Example of a Row class that logs insert data for multiple tables

The custom logic may be common to multiple tables. Instead of implementing the same custom logic in every one of your Table classes, you can implement the code for such actions in the definition of a Row class, and use this Row in each of your Table classes.

In this example, the logging code is identical in all table classes.

  1. class MyLoggingRow extends Zend_Db_Table_Row_Abstract
  2. {
  3.     protected function _insert()
  4.     {
  5.         $log = Zend_Registry::get('database_log');
  6.         $log->info(Zend_Debug::dump($this->_data,
  7.                                     "INSERT: $this->_tableClass",
  8.                                     false)
  9.                   );
  10.     }
  11. }
  12.  
  13. class Bugs extends Zend_Db_Table_Abstract
  14. {
  15.     protected $_name = 'bugs';
  16.     protected $_rowClass = 'MyLoggingRow';
  17. }
  18.  
  19. class Products extends Zend_Db_Table_Abstract
  20. {
  21.     protected $_name = 'products';
  22.     protected $_rowClass = 'MyLoggingRow';
  23. }

Define Inflection in Zend_Db_Table_Row

Some people prefer that the table class name match a table name in the RDBMS by using a string transformation called inflection.

Zend_Db classes do not implement inflection by default. See the chapter about extending inflection for an explanation of this policy.

If you prefer to use inflection, then you must implement the transformation yourself, by overriding the _transformColumn() method in a custom Row class, and using that custom Row class when you perform queries against your Table class.

Example #17 Example of defining an inflection transformation

This allows you to use an inflected version of the column name in the accessors. The Row class uses the _transformColumn() method to change the name you use to the native column name in the database table.

  1. class MyInflectedRow extends Zend_Db_Table_Row_Abstract
  2. {
  3.     protected function _transformColumn($columnName)
  4.     {
  5.         $nativeColumnName = myCustomInflector($columnName);
  6.         return $nativeColumnName;
  7.     }
  8. }
  9.  
  10. class Bugs extends Zend_Db_Table_Abstract
  11. {
  12.     protected $_name = 'bugs';
  13.     protected $_rowClass = 'MyInflectedRow';
  14. }
  15.  
  16. $bugs = new Bugs();
  17. $row = $bugs->fetchNew();
  18.  
  19. // Use camelcase column names, and rely on the
  20. // transformation function to change it into the
  21. // native representation.
  22. $row->bugDescription = 'New description';

You are responsible for writing the functions to perform inflection transformation. Zend Framework does not provide such a function.

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