* - column names: member.member_srl => "member"."member_srl"
* - expressions: SUM(member.member_srl) => SUM("member"."member_srl")
*
* @author Corina Udrescu (corina.udrescu@arnia.ro)
* @package classes\xml\xmlquery
* @version 0.1
*/
class DBParser
{
/**
* Character for escape target value on the left
*
* For example, in CUBRID left and right escape
* chars are the same, the double quote - "
* But for SQL Server, the escape is made with
* [double brackets], so the left and right char differ
*
*
* @var string
*/
var $escape_char_left;
/**
* Character for escape target value on the right
*
* For example, in CUBRID left and right escape
* chars are the same, the double quote - "
* But for SQL Server, the escape is made with
* [double brackets], so the left and right char differ
*
* @var string
*/
var $escape_char_right;
/**
* Table prefix string
*
* Default is "xe_"
*
* @var string
*/
var $table_prefix;
/**
* Constructor
*
* @param string $escape_char_left
* @param string $escape_char_right
* @param string $table_prefix
*
* @return void
*/
function DBParser($escape_char_left, $escape_char_right = "", $table_prefix = "xe_")
{
$this->escape_char_left = $escape_char_left;
if ($escape_char_right !== "")$this->escape_char_right = $escape_char_right;
else $this->escape_char_right = $escape_char_left;
$this->table_prefix = $table_prefix;
}
/**
* Get escape character
*
* @param string $leftOrRight left or right
* @return string
*/
function getEscapeChar($leftOrRight)
{
if ($leftOrRight === 'left')return $this->escape_char_left;
else return $this->escape_char_right;
}
/**
* Escape the value
*
* @param mixed $name
* @return string
*/
function escape($name)
{
return $this->escape_char_left . $name . $this->escape_char_right;
}
/**
* Escape the string value
*
* @param string $name
* @return string
*/
function escapeString($name)
{
return "'".$this->escapeStringValue($name)."'";
}
/**
* Escape the string value
*
* @param string $value
* @return string
*/
function escapeStringValue($value)
{
if($value == "*") return $value;
if (is_string($value)) return $value = str_replace("'","''",$value);
return $value;
}
/**
* Return table full name
*
* @param string $name table name without table prefix
*
* @return string table full name with table prefix
*/
function parseTableName($name)
{
return $this->table_prefix . $name;
}
/**
* Return column name after escape
*
* @param string $name column name before escape
*
* @return string column name after escape
*/
function parseColumnName($name)
{
return $this->escapeColumn($name);
}
/**
* Escape column name
*
* @param string $column_name
* @return string column name with db name
*/
function escapeColumn($column_name)
{
if($this->isUnqualifiedColumnName($column_name))
return $this->escape($column_name);
if($this->isQualifiedColumnName($column_name)){
list($table, $column) = explode('.', $column_name);
// $table can also be an alias, so the prefix should not be added
return $this->escape($table).'.'.$this->escape($column);
//return $this->escape($this->parseTableName($table)).'.'.$this->escape($column);
}
}
/**
* Checks to see if a given column name is unqualified
*
* Ex: "member_srl" -> unqualified
* "member"."member_srl" -> qualified
*
* @param string $column_name
* @return bool
*/
function isUnqualifiedColumnName($column_name)
{
if(strpos($column_name,'.')===FALSE && strpos($column_name,'(')===FALSE) return TRUE;
return FALSE;
}
/**
* Checks to see if a given column name is qualified
*
* Ex: "member_srl" -> unqualified
* "member"."member_srl" -> qualified
*
* @param string $column_name
* @return bool
*/
function isQualifiedColumnName($column_name)
{
if(strpos($column_name,'.')!==FALSE && strpos($column_name,'(')===FALSE) return TRUE;
return FALSE;
}
/**
* Escapes a query expression
*
* An expression can be:
*
* - a column name: "member_srl" or "xe_member"."member_srl"
*
- an expression:
*
* - LEFT(UPPER("content"))
* - readed_count + voted_count
* - CAST(regdate as DATE)
*
*
*
*
* @param $column_name
* @return string
*/
function parseExpression($column_name)
{
$functions = preg_split('/([\+\-\*\/\ ])/', $column_name, -1, PREG_SPLIT_DELIM_CAPTURE|PREG_SPLIT_NO_EMPTY);
foreach($functions as $k => $v){
$function = &$functions[$k];
if(strlen($function)==1) continue; // skip delimiters
$pos = strrpos("(", $function);
$matches = preg_split('/([a-zA-Z0-9_*]+)/', $function, -1, PREG_SPLIT_DELIM_CAPTURE|PREG_SPLIT_NO_EMPTY);
$total_brackets = substr_count($function, "(");
$brackets = 0;
foreach($matches as $i => $j){
$match = &$matches[$i];
if($match == '(') {$brackets++; continue;}
if(strpos($match,')') !== FALSE) continue;
if(in_array($match, array(',', '.'))) continue;
if($brackets == $total_brackets){
if(!is_numeric($match) && !in_array(strtoupper($match), array('UNSIGNED', 'INTEGER', 'AS'))) {
$match = $this->escapeColumnExpression($match);
}
}
}
$function = implode('', $matches);
}
return implode('', $functions);
}
/**
* Checks if a given argument is an asterisk
*
* @param string $column_name
* @return bool
*/
function isStar($column_name)
{
if(substr($column_name,-1) == '*') return TRUE;
return FALSE;
}
/**
* Checks to see if expression is an aggregate star function
* like count(*)
*
* @param string $column_name
* @return bool
*/
function isStarFunction($column_name)
{
if(strpos($column_name, "(*)")!==FALSE) return TRUE;
return FALSE;
}
/**
* Return column name after escape
* @param string $column_name
* @return string
*/
function escapeColumnExpression($column_name)
{
if($this->isStar($column_name)) return $column_name;
if($this->isStarFunction($column_name))
{
return $column_name;
}
if(strpos(strtolower($column_name), 'distinct') !== FALSE) return $column_name;
return $this->escapeColumn($column_name);
}
}