Insert.php

<?php

namespace Drupal\Core\Database\Driver\mysql;

use Drupal\Core\Database\Query\Insert as QueryInsert;

/**
 * MySQL implementation of \Drupal\Core\Database\Query\Insert.
 */
class Insert extends QueryInsert {
    public function execute() {
        if (!$this->preExecute()) {
            return NULL;
        }
        // If we're selecting from a SelectQuery, finish building the query and
        // pass it back, as any remaining options are irrelevant.
        if (empty($this->fromQuery)) {
            $max_placeholder = 0;
            $values = [];
            foreach ($this->insertValues as $insert_values) {
                foreach ($insert_values as $value) {
                    $values[':db_insert_placeholder_' . $max_placeholder++] = $value;
                }
            }
        }
        else {
            $values = $this->fromQuery
                ->getArguments();
        }
        $last_insert_id = $this->connection
            ->query((string) $this, $values, $this->queryOptions);
        // Re-initialize the values array so that we can re-use this query.
        $this->insertValues = [];
        return $last_insert_id;
    }
    public function __toString() {
        // Create a sanitized comment string to prepend to the query.
        $comments = $this->connection
            ->makeComment($this->comments);
        // Default fields are always placed first for consistency.
        $insert_fields = array_merge($this->defaultFields, $this->insertFields);
        $insert_fields = array_map(function ($field) {
            return $this->connection
                ->escapeField($field);
        }, $insert_fields);
        // If we're selecting from a SelectQuery, finish building the query and
        // pass it back, as any remaining options are irrelevant.
        if (!empty($this->fromQuery)) {
            $insert_fields_string = $insert_fields ? ' (' . implode(', ', $insert_fields) . ') ' : ' ';
            return $comments . 'INSERT INTO {' . $this->table . '}' . $insert_fields_string . $this->fromQuery;
        }
        $query = $comments . 'INSERT INTO {' . $this->table . '} (' . implode(', ', $insert_fields) . ') VALUES ';
        $values = $this->getInsertPlaceholderFragment($this->insertValues, $this->defaultFields);
        $query .= implode(', ', $values);
        return $query;
    }

}