File Source for Preparator.php

<?php
require_once RDFAPI_INCLUDE_DIR . 'sparql/SparqlEngineDb/Offsetter.php';
/**
* This class takes care of prepared statements:
* Preparing them in the database, replacing
*
* @author Christian Weiske <cweiske@cweiske.de>
*
* @package sparql
*/
class SparqlEngineDb_Preparator
{
public function __construct(Query $query, ADOConnection $dbConn)
{
$this->query = $query;
$this->dbConn = $dbConn;
$this->arPrefixes = $this->query->getPrefixes();
}//public function __construct(Query $query, ADOConnection $dbConn)
/**
* Converts the given queries into sql prepared statments,
* calls the prepare command in the database and returns
* an array consisting of subarrays. They contain
* the db's prepared statement as first value, and an array
* of variable positions as second value (key is the position,
* the sparql variable is the value).
*
* @param array $arQueries Array of sql queries part arrays
* @param array $arPlaceholders Array of sparql (variable name =>
* placeholder name) pairs
* @return array Array of (prepared statment, variable positions) pairs
*/
public function prepareInDb($arQueries, $arPlaceholders)
{
$arDbStatements = array();
foreach ($arQueries as $arQuery) {
list($strPrepared, $arVariablePositions) = $this->replacePlaceholders(
implode('', $arQuery),
$arPlaceholders
);
if (count($arQueries) == 1) {
//I currently haven't seens one case in which the count was > 1
//if that happens, we will need to add a fix
$strPrepared .= SparqlEngineDb_Offsetter::getLimitSql(
$this->query,
$this->dbConn
);
}
$stmt = $this->dbConn->Prepare($strPrepared);
$arDbStatements[] = array(
$stmt,
$arVariablePositions
);
}
return $arDbStatements;
}//public function prepareInDb($arQueries, $arPlaceholders)
/**
* Replaces the placeholders in the given SQL statement with real
* SQL prepared statements placeholders.
*
* @param string $strQuery SQL query with placeholders
* @param array $arPlaceholders Array of sparql (variable name =>
* placeholder name) pairs
* @return array (prepared sql query string, variable positions) pair
*/
protected function replacePlaceholders($strQuery, $arPlaceholders)
{
$arVariablePositions = array();
$this->arTmpVariablePositions = array();
$this->arTmpPlaceholders = $arPlaceholders;
$strQuery = preg_replace_callback(
'/@\\$%_PLACEHOLDER_[0-9]+_%\\$@/',
array($this, 'replacePlaceholdersCb'),
$strQuery
);
return array($strQuery, $this->arTmpVariablePositions);
}//protected function replacePlaceholders($strQuery, $arPlaceholders)
/**
* Callback method internally used by replacePlaceholders() method.
*/
protected function replacePlaceholdersCb($matches)
{
$strPlaceholder = $matches[0];
$strSparqlVariable = array_search(
$strPlaceholder,
$this->arTmpPlaceholders
);
$strDbPlaceholder = $this->dbConn->Param($strSparqlVariable);
$this->arTmpVariablePositions[] = $strSparqlVariable;
return $strDbPlaceholder;
}//protected function replacePlaceholdersCb($matches)
/**
* Executes the given prepared statments, filling the placeholders
* with the given values.
*
* @param array $arDbStatements Return value of prepareInDb()
* @param array $arVariableValues Array of (variable name, value) pairs
*
* @return array Array of database results as returned by Execute()
*/
public function execute($arDbStatements, $arVariableValues)
{
$arResults = array();
$oldmode = $this->dbConn->SetFetchMode(ADODB_FETCH_ASSOC);
foreach ($arDbStatements as $arStatement) {
list($stmt, $arVariablePositions) = $arStatement;
$arVariables = $this->createVariableArray(
$arVariablePositions,
$arVariableValues
);
$arResults[] = $this->dbConn->Execute($stmt, $arVariables);
}
$this->dbConn->SetFetchMode($oldmode);
return $arResults;
}//public function execute($arDbStatements, $arVariableValues)
/**
* Creates an array full of variables to be passed to the Execute() method
* of the database connection object.
* Uses the variable positions array to get the positions of the variables
* in the result array, and the variable value array to get the actual
* values for the prepared statement.
*
* @param array $arVariablePositions Positions of the variables as returned
* by replacePlaceholders().
* @param array $arVariableValues Array of (variable name, value) pairs
*
* @return array Array of variable values
*/
protected function createVariableArray($arVariablePositions, $arVariableValues)
{
$arVariables = array();
foreach ($arVariablePositions as $nPos => $strVariable) {
if (!isset($arVariableValues[$strVariable])) {
throw new Exception('No value for variable "' . $strVariable . '" in prepared statement');
}
$strValue = self::replacePrefix(
$arVariableValues[$strVariable],
$this->arPrefixes
);
$arVariables[$nPos] = $strValue;
}
return $arVariables;
}//protected function createVariableArray($arVariablePositions, $arVariableValues)
/**
* Replaces all placeholders with their actual values.
*/
public function replacePlaceholdersWithVariables($strQuery, $arPlaceholders, $arVariableValues)
{
$this->arTmpPlaceholders = $arPlaceholders;
$this->arTmpVariableValues = $arVariableValues;
$strQuery = preg_replace_callback(
'/@\\$%_PLACEHOLDER_[0-9]+_%\\$@/',
array($this, 'replacePlaceholdersWithVariablesCb'),
$strQuery
);
return $strQuery;
}//public function replacePlaceholdersWithVariables($strQuery, $arPlaceholders, $arVariableValues)
/**
* Callback method internally used by
* replacePlaceholdersWithVariables() method.
*/
protected function replacePlaceholdersWithVariablesCb($matches)
{
$strPlaceholder = $matches[0];
$strSparqlVariable = array_search(
$strPlaceholder,
$this->arTmpPlaceholders
);
return $this->dbConn->qstr(
self::replacePrefix(
$this->arTmpVariableValues[$strSparqlVariable],
$this->arPrefixes
)
);
}//protected function replacePlaceholdersWithVariablesCb($matches)
protected static function replacePrefix($strValue, $arPrefixes)
{
//replace prefixes?
if (count($arParts = explode(':', $strValue, 2)) == 2) {
if (isset($arPrefixes[$arParts[0]])) {
$strValue = $arPrefixes[$arParts[0]] . $arParts[1];
}
}
return $strValue;
}//protected static function replacePrefix($strValue, $arPrefixes)
}//class SparqlEngineDb_Preparator
?>

Documentation generated on Fri, 1 Jun 2007 16:50:25 +0200 by phpDocumentor 1.3.2

Source for file Preparator.php