IteratedQuery Class Reference

IteratedQuery provides a memory-efficient way to query and return large data sets. More...

Inheritance diagram for IteratedQuery:

Collaboration diagram for IteratedQuery:

Public Member Functions
	__construct ($class, $constraints="")
	_runQuery ()
	execute ()
Public Member Functions inherited from AbstractQuery
	constraints ($constraints)
	Sets the constraint clause for the Query. More...
	filter ($filter)
	Sets a filter to constrain the fields retrieved when the query is executed. More...
	params ($params)
	Sets the bound parameters array. More...
	bind ()
	Binds placeholders to parameter values. More...

Static Public Member Functions
static	create ($class, $constraints="")

Additional Inherited Members
Public Attributes inherited from AbstractQuery
	$class
	$constraints
	$filter
	$params

Detailed Description

IteratedQuery provides a memory-efficient way to query and return large data sets.

Whereas the default Query class and the IndexedQuery and GroupedQuery classes all pull the full result set into memory when the query is executed, IteratedQuery leaves the connection to the database open and retrieves the results one row at a time. The results are returned wrapped in a DataItemIterator, allowing them to be used in foreach(...) statements, etc.

In general it is recommended that IteratedQuery only be used in situations where the result would take up too much memory to be processed using a standard Query object.

Author

andy

Definition at line 163 of file iterated_query.inc.

Constructor & Destructor Documentation

__construct()

IteratedQuery::__construct	(		$class,
			$constraints = ""
	)

Reimplemented from AbstractQuery.

Definition at line 165 of file iterated_query.inc.

     {
          parent::__construct($class, $constraints);
     }

Member Function Documentation

_runQuery()

IteratedQuery::_runQuery

(

)

Definition at line 170 of file iterated_query.inc.

     {
          $prototype = new $this->class;
          $prototype->filter = $this->filter;
     
          $order_by_idx = strpos(strtoupper($this->constraints), "ORDER BY");
          $orderBy = ""; 
          
          if ($order_by_idx !== false)
          {
               $orderBy = substr($this->constraints, $order_by_idx);
               
               $this->constraints = substr($this->constraints, 0, $order_by_idx);
          } 
          
          if ($this->constraints == "") $this->constraints = "WHERE 1=1"; //TODO - tidy this up some day
          $this->constraints .= " ".$prototype->getIdentityConstraint();
          
          $query = "SELECT ".$prototype->getFieldList()." FROM {$prototype->table} {$this->tableAlias} {$this->constraints} $orderBy";
          
          trace("$query", 3);
          
          try
          {
               $db = ConnectionManager::getConnection();
               
               $result = $db->prepare($query);
               $result->execute($this->params);
               $this->rowCount = $result->rowCount();
               return $result;
          }
          catch(PDOException $e)
          {
               throw new FakoliException($e->getMessage());
          }
     }

create()

static IteratedQuery::create (   $class,   $constraints = ""  )

static

Definition at line 212 of file iterated_query.inc.

     {
          return new IteratedQuery($class, $constraints);
     }

execute()

IteratedQuery::execute

(

)

Reimplemented from AbstractQuery.

Definition at line 207 of file iterated_query.inc.

     {
          return new DataItemIterator($this);
     }

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The documentation for this class was generated from the following file:

• C:/code/cms.sonjara.com/framework/iterated_query.inc