system/classes/Db_MySQL.php
protected function queryStringFromArray($dataMember, $opening, $sep, $quote = true, $set = false)
    {
        if (empty($this->$dataMember)) {
            return 0;
        }
        $this->query .= $opening;
        $count = count($this->$dataMember);
        for($i=0; $i<$count; $i++) {
            
            // Is this a normal situation, or are we outputting SET values for table creation statement?
            if ($set == false) {
                $this->query .= $this->getArrayItem($dataMember, $i, $quote);
            }
            else {
                // If we are creating a table, then we need to execute a diff method
                // so we can do some type checking on the column value. I.E. 'varchar' = 'varchar[255]'
                $this->query .= $this->getSetItem($dataMember, $i, $quote);
            }
            
            if ($count-1 != $i) {
                $this->query .= $sep;
            }
        }
    }
protected function queryStringFromArray($dataMember, $opening, $sep, $quote = true, $set = false)
    {
        if (empty($this->$dataMember)) {
            return 0;
        }
        $this->query .= $opening;
        $count = count($this->$dataMember);
        for($i=0; $i<$count; $i++) {
            
            // Is this a normal situation, or are we outputting SET values for table creation statement?
            if ($set == false) {
                $this->query .= $this->getArrayItem($dataMember, $i, $quote);
            }
            else {
                // If we are creating a table, then we need to execute a diff method
                // so we can do some type checking on the column value. I.E. 'varchar' = 'varchar[255]'
                $this->query .= $this->getSetItem($dataMember, $i, $quote);
            }
            
            if ($count-1 != $i) {
                $this->query .= $sep;
            }
        }
    }
Create a string from a single-demensional Database class array.
It calls getArrayItem() for each item and expects the returned result to be a string.
It assumes the following structure:
[
item1,
item2,
item3
]
An item can be another array if getArrayItem() knows how to translate it into a string.