protected function extractDefault($defaultValue)
{
    if($defaultValue==='true')
        $this->defaultValue=true;
    elseif($defaultValue==='false')
        $this->defaultValue=false;
    elseif(strpos($defaultValue,'nextval')===0)
        $this->defaultValue=null;
    elseif(preg_match('/^\'(.*)\'::/',$defaultValue,$matches))
        $this->defaultValue=$this->typecast(str_replace("''","'",$matches[1]));
    elseif(preg_match('/^(-?\d+(\.\d*)?)(::.*)?$/',$defaultValue,$matches))
        $this->defaultValue=$this->typecast($matches[1]);
    // else is null
}

protected function extractLimit($dbType)
{
    if(strpos($dbType,'('))
    {
        if (preg_match('/^time.*\((.*)\)/',$dbType,$matches))
        {
            $this->precision=(int)$matches[1];
        }
        elseif (preg_match('/\((.*)\)/',$dbType,$matches))
        {
            $values=explode(',',$matches[1]);
            $this->size=$this->precision=(int)$values[0];
            if(isset($values[1]))
                $this->scale=(int)$values[1];
        }
    }
}

protected function extractType($dbType)
{
    if(strpos($dbType,'[')!==false || strpos($dbType,'char')!==false || strpos($dbType,'text')!==false)
        $this->type='string';
    elseif(strpos($dbType,'bool')!==false)
        $this->type='boolean';
    elseif(preg_match('/(real|float|double)/',$dbType))
        $this->type='double';
    elseif(preg_match('/(integer|oid|serial|smallint)/',$dbType))
        $this->type='integer';
    else
        $this->type='string';
}