Initial

system/Database/MySQLi/Builder.php

@@ -0,0 +1,56 @@
+<?php
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\Database\MySQLi;
+
+use CodeIgniter\Database\BaseBuilder;
+
+/**
+ * Builder for MySQLi
+ */
+class Builder extends BaseBuilder
+{
+    /**
+     * Identifier escape character
+     *
+     * @var string
+     */
+    protected $escapeChar = '`';
+
+    /**
+     * Specifies which sql statements
+     * support the ignore option.
+     *
+     * @var array
+     */
+    protected $supportedIgnoreStatements = [
+        'update' => 'IGNORE',
+        'insert' => 'IGNORE',
+        'delete' => 'IGNORE',
+    ];
+
+    /**
+     * FROM tables
+     *
+     * Groups tables in FROM clauses if needed, so there is no confusion
+     * about operator precedence.
+     *
+     * Note: This is only used (and overridden) by MySQL.
+     */
+    protected function _fromTables(): string
+    {
+        if (! empty($this->QBJoin) && count($this->QBFrom) > 1) {
+            return '(' . implode(', ', $this->QBFrom) . ')';
+        }
+
+        return implode(', ', $this->QBFrom);
+    }
+}

system/Database/MySQLi/Connection.php

@@ -0,0 +1,605 @@
+<?php
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\Database\MySQLi;
+
+use CodeIgniter\Database\BaseConnection;
+use CodeIgniter\Database\Exceptions\DatabaseException;
+use LogicException;
+use MySQLi;
+use mysqli_sql_exception;
+use stdClass;
+use Throwable;
+
+/**
+ * Connection for MySQLi
+ */
+class Connection extends BaseConnection
+{
+    /**
+     * Database driver
+     *
+     * @var string
+     */
+    public $DBDriver = 'MySQLi';
+
+    /**
+     * DELETE hack flag
+     *
+     * Whether to use the MySQL "delete hack" which allows the number
+     * of affected rows to be shown. Uses a preg_replace when enabled,
+     * adding a bit more processing to all queries.
+     *
+     * @var bool
+     */
+    public $deleteHack = true;
+
+    /**
+     * Identifier escape character
+     *
+     * @var string
+     */
+    public $escapeChar = '`';
+
+    /**
+     * MySQLi object
+     *
+     * Has to be preserved without being assigned to $conn_id.
+     *
+     * @var MySQLi
+     */
+    public $mysqli;
+
+    /**
+     * MySQLi constant
+     *
+     * For unbuffered queries use `MYSQLI_USE_RESULT`.
+     *
+     * Default mode for buffered queries uses `MYSQLI_STORE_RESULT`.
+     *
+     * @var int
+     */
+    public $resultMode = MYSQLI_STORE_RESULT;
+
+    /**
+     * Connect to the database.
+     *
+     * @throws DatabaseException
+     *
+     * @return mixed
+     */
+    public function connect(bool $persistent = false)
+    {
+        // Do we have a socket path?
+        if ($this->hostname[0] === '/') {
+            $hostname = null;
+            $port     = null;
+            $socket   = $this->hostname;
+        } else {
+            $hostname = ($persistent === true) ? 'p:' . $this->hostname : $this->hostname;
+            $port     = empty($this->port) ? null : $this->port;
+            $socket   = '';
+        }
+
+        $clientFlags  = ($this->compress === true) ? MYSQLI_CLIENT_COMPRESS : 0;
+        $this->mysqli = mysqli_init();
+
+        mysqli_report(MYSQLI_REPORT_ALL & ~MYSQLI_REPORT_INDEX);
+
+        $this->mysqli->options(MYSQLI_OPT_CONNECT_TIMEOUT, 10);
+
+        if (isset($this->strictOn)) {
+            if ($this->strictOn) {
+                $this->mysqli->options(
+                    MYSQLI_INIT_COMMAND,
+                    "SET SESSION sql_mode = CONCAT(@@sql_mode, ',', 'STRICT_ALL_TABLES')"
+                );
+            } else {
+                $this->mysqli->options(
+                    MYSQLI_INIT_COMMAND,
+                    "SET SESSION sql_mode = REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(
+                                        @@sql_mode,
+                                        'STRICT_ALL_TABLES,', ''),
+                                    ',STRICT_ALL_TABLES', ''),
+                                'STRICT_ALL_TABLES', ''),
+                            'STRICT_TRANS_TABLES,', ''),
+                        ',STRICT_TRANS_TABLES', ''),
+                    'STRICT_TRANS_TABLES', '')"
+                );
+            }
+        }
+
+        if (is_array($this->encrypt)) {
+            $ssl = [];
+
+            if (! empty($this->encrypt['ssl_key'])) {
+                $ssl['key'] = $this->encrypt['ssl_key'];
+            }
+            if (! empty($this->encrypt['ssl_cert'])) {
+                $ssl['cert'] = $this->encrypt['ssl_cert'];
+            }
+            if (! empty($this->encrypt['ssl_ca'])) {
+                $ssl['ca'] = $this->encrypt['ssl_ca'];
+            }
+            if (! empty($this->encrypt['ssl_capath'])) {
+                $ssl['capath'] = $this->encrypt['ssl_capath'];
+            }
+            if (! empty($this->encrypt['ssl_cipher'])) {
+                $ssl['cipher'] = $this->encrypt['ssl_cipher'];
+            }
+
+            if (! empty($ssl)) {
+                if (isset($this->encrypt['ssl_verify'])) {
+                    if ($this->encrypt['ssl_verify']) {
+                        if (defined('MYSQLI_OPT_SSL_VERIFY_SERVER_CERT')) {
+                            $this->mysqli->options(MYSQLI_OPT_SSL_VERIFY_SERVER_CERT, 1);
+                        }
+                    }
+                    // Apparently (when it exists), setting MYSQLI_OPT_SSL_VERIFY_SERVER_CERT
+                    // to FALSE didn't do anything, so PHP 5.6.16 introduced yet another
+                    // constant ...
+                    //
+                    // https://secure.php.net/ChangeLog-5.php#5.6.16
+                    // https://bugs.php.net/bug.php?id=68344
+                    elseif (defined('MYSQLI_CLIENT_SSL_DONT_VERIFY_SERVER_CERT') && version_compare($this->mysqli->client_info, 'mysqlnd 5.6', '>=')) {
+                        $clientFlags += MYSQLI_CLIENT_SSL_DONT_VERIFY_SERVER_CERT;
+                    }
+                }
+
+                $this->mysqli->ssl_set(
+                    $ssl['key'] ?? null,
+                    $ssl['cert'] ?? null,
+                    $ssl['ca'] ?? null,
+                    $ssl['capath'] ?? null,
+                    $ssl['cipher'] ?? null
+                );
+            }
+
+            $clientFlags += MYSQLI_CLIENT_SSL;
+        }
+
+        try {
+            if ($this->mysqli->real_connect(
+                $hostname,
+                $this->username,
+                $this->password,
+                $this->database,
+                $port,
+                $socket,
+                $clientFlags
+            )) {
+                // Prior to version 5.7.3, MySQL silently downgrades to an unencrypted connection if SSL setup fails
+                if (($clientFlags & MYSQLI_CLIENT_SSL) && version_compare($this->mysqli->client_info, 'mysqlnd 5.7.3', '<=')
+                    && empty($this->mysqli->query("SHOW STATUS LIKE 'ssl_cipher'")->fetch_object()->Value)
+                ) {
+                    $this->mysqli->close();
+                    $message = 'MySQLi was configured for an SSL connection, but got an unencrypted connection instead!';
+                    log_message('error', $message);
+
+                    if ($this->DBDebug) {
+                        throw new DatabaseException($message);
+                    }
+
+                    return false;
+                }
+
+                if (! $this->mysqli->set_charset($this->charset)) {
+                    log_message('error', "Database: Unable to set the configured connection charset ('{$this->charset}').");
+
+                    $this->mysqli->close();
+
+                    if ($this->DBDebug) {
+                        throw new DatabaseException('Unable to set client connection character set: ' . $this->charset);
+                    }
+
+                    return false;
+                }
+
+                return $this->mysqli;
+            }
+        } catch (Throwable $e) {
+            // Clean sensitive information from errors.
+            $msg = $e->getMessage();
+
+            $msg = str_replace($this->username, '****', $msg);
+            $msg = str_replace($this->password, '****', $msg);
+
+            throw new DatabaseException($msg, $e->getCode(), $e);
+        }
+
+        return false;
+    }
+
+    /**
+     * Keep or establish the connection if no queries have been sent for
+     * a length of time exceeding the server's idle timeout.
+     */
+    public function reconnect()
+    {
+        $this->close();
+        $this->initialize();
+    }
+
+    /**
+     * Close the database connection.
+     */
+    protected function _close()
+    {
+        $this->connID->close();
+    }
+
+    /**
+     * Select a specific database table to use.
+     */
+    public function setDatabase(string $databaseName): bool
+    {
+        if ($databaseName === '') {
+            $databaseName = $this->database;
+        }
+
+        if (empty($this->connID)) {
+            $this->initialize();
+        }
+
+        if ($this->connID->select_db($databaseName)) {
+            $this->database = $databaseName;
+
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Returns a string containing the version of the database being used.
+     */
+    public function getVersion(): string
+    {
+        if (isset($this->dataCache['version'])) {
+            return $this->dataCache['version'];
+        }
+
+        if (empty($this->mysqli)) {
+            $this->initialize();
+        }
+
+        return $this->dataCache['version'] = $this->mysqli->server_info;
+    }
+
+    /**
+     * Executes the query against the database.
+     *
+     * @return mixed
+     */
+    protected function execute(string $sql)
+    {
+        while ($this->connID->more_results()) {
+            $this->connID->next_result();
+            if ($res = $this->connID->store_result()) {
+                $res->free();
+            }
+        }
+
+        try {
+            return $this->connID->query($this->prepQuery($sql), $this->resultMode);
+        } catch (mysqli_sql_exception $e) {
+            log_message('error', $e->getMessage());
+
+            if ($this->DBDebug) {
+                throw $e;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Prep the query. If needed, each database adapter can prep the query string
+     */
+    protected function prepQuery(string $sql): string
+    {
+        // mysqli_affected_rows() returns 0 for "DELETE FROM TABLE" queries. This hack
+        // modifies the query so that it a proper number of affected rows is returned.
+        if ($this->deleteHack === true && preg_match('/^\s*DELETE\s+FROM\s+(\S+)\s*$/i', $sql)) {
+            return trim($sql) . ' WHERE 1=1';
+        }
+
+        return $sql;
+    }
+
+    /**
+     * Returns the total number of rows affected by this query.
+     */
+    public function affectedRows(): int
+    {
+        return $this->connID->affected_rows ?? 0;
+    }
+
+    /**
+     * Platform-dependant string escape
+     */
+    protected function _escapeString(string $str): string
+    {
+        if (! $this->connID) {
+            $this->initialize();
+        }
+
+        return $this->connID->real_escape_string($str);
+    }
+
+    /**
+     * Escape Like String Direct
+     * There are a few instances where MySQLi queries cannot take the
+     * additional "ESCAPE x" parameter for specifying the escape character
+     * in "LIKE" strings, and this handles those directly with a backslash.
+     *
+     * @param string|string[] $str Input string
+     *
+     * @return string|string[]
+     */
+    public function escapeLikeStringDirect($str)
+    {
+        if (is_array($str)) {
+            foreach ($str as $key => $val) {
+                $str[$key] = $this->escapeLikeStringDirect($val);
+            }
+
+            return $str;
+        }
+
+        $str = $this->_escapeString($str);
+
+        // Escape LIKE condition wildcards
+        return str_replace(
+            [$this->likeEscapeChar, '%', '_'],
+            ['\\' . $this->likeEscapeChar, '\\' . '%', '\\' . '_'],
+            $str
+        );
+    }
+
+    /**
+     * Generates the SQL for listing tables in a platform-dependent manner.
+     * Uses escapeLikeStringDirect().
+     */
+    protected function _listTables(bool $prefixLimit = false): string
+    {
+        $sql = 'SHOW TABLES FROM ' . $this->escapeIdentifiers($this->database);
+
+        if ($prefixLimit !== false && $this->DBPrefix !== '') {
+            return $sql . " LIKE '" . $this->escapeLikeStringDirect($this->DBPrefix) . "%'";
+        }
+
+        return $sql;
+    }
+
+    /**
+     * Generates a platform-specific query string so that the column names can be fetched.
+     */
+    protected function _listColumns(string $table = ''): string
+    {
+        return 'SHOW COLUMNS FROM ' . $this->protectIdentifiers($table, true, null, false);
+    }
+
+    /**
+     * Returns an array of objects with field data
+     *
+     * @throws DatabaseException
+     *
+     * @return stdClass[]
+     */
+    protected function _fieldData(string $table): array
+    {
+        $table = $this->protectIdentifiers($table, true, null, false);
+
+        if (($query = $this->query('SHOW COLUMNS FROM ' . $table)) === false) {
+            throw new DatabaseException(lang('Database.failGetFieldData'));
+        }
+        $query = $query->getResultObject();
+
+        $retVal = [];
+
+        for ($i = 0, $c = count($query); $i < $c; $i++) {
+            $retVal[$i]       = new stdClass();
+            $retVal[$i]->name = $query[$i]->Field;
+
+            sscanf($query[$i]->Type, '%[a-z](%d)', $retVal[$i]->type, $retVal[$i]->max_length);
+
+            $retVal[$i]->nullable    = $query[$i]->Null === 'YES';
+            $retVal[$i]->default     = $query[$i]->Default;
+            $retVal[$i]->primary_key = (int) ($query[$i]->Key === 'PRI');
+        }
+
+        return $retVal;
+    }
+
+    /**
+     * Returns an array of objects with index data
+     *
+     * @throws DatabaseException
+     * @throws LogicException
+     *
+     * @return stdClass[]
+     */
+    protected function _indexData(string $table): array
+    {
+        $table = $this->protectIdentifiers($table, true, null, false);
+
+        if (($query = $this->query('SHOW INDEX FROM ' . $table)) === false) {
+            throw new DatabaseException(lang('Database.failGetIndexData'));
+        }
+
+        if (! $indexes = $query->getResultArray()) {
+            return [];
+        }
+
+        $keys = [];
+
+        foreach ($indexes as $index) {
+            if (empty($keys[$index['Key_name']])) {
+                $keys[$index['Key_name']]       = new stdClass();
+                $keys[$index['Key_name']]->name = $index['Key_name'];
+
+                if ($index['Key_name'] === 'PRIMARY') {
+                    $type = 'PRIMARY';
+                } elseif ($index['Index_type'] === 'FULLTEXT') {
+                    $type = 'FULLTEXT';
+                } elseif ($index['Non_unique']) {
+                    $type = $index['Index_type'] === 'SPATIAL' ? 'SPATIAL' : 'INDEX';
+                } else {
+                    $type = 'UNIQUE';
+                }
+
+                $keys[$index['Key_name']]->type = $type;
+            }
+
+            $keys[$index['Key_name']]->fields[] = $index['Column_name'];
+        }
+
+        return $keys;
+    }
+
+    /**
+     * Returns an array of objects with Foreign key data
+     *
+     * @throws DatabaseException
+     *
+     * @return stdClass[]
+     */
+    protected function _foreignKeyData(string $table): array
+    {
+        $sql = '
+                    SELECT
+                        tc.CONSTRAINT_NAME,
+                        tc.TABLE_NAME,
+                        kcu.COLUMN_NAME,
+                        rc.REFERENCED_TABLE_NAME,
+                        kcu.REFERENCED_COLUMN_NAME
+                    FROM information_schema.TABLE_CONSTRAINTS AS tc
+                    INNER JOIN information_schema.REFERENTIAL_CONSTRAINTS AS rc
+                        ON tc.CONSTRAINT_NAME = rc.CONSTRAINT_NAME
+                        AND tc.CONSTRAINT_SCHEMA = rc.CONSTRAINT_SCHEMA
+                    INNER JOIN information_schema.KEY_COLUMN_USAGE AS kcu
+                        ON tc.CONSTRAINT_NAME = kcu.CONSTRAINT_NAME
+                        AND tc.CONSTRAINT_SCHEMA = kcu.CONSTRAINT_SCHEMA
+                    WHERE
+                        tc.CONSTRAINT_TYPE = ' . $this->escape('FOREIGN KEY') . ' AND
+                        tc.TABLE_SCHEMA = ' . $this->escape($this->database) . ' AND
+                        tc.TABLE_NAME = ' . $this->escape($table);
+
+        if (($query = $this->query($sql)) === false) {
+            throw new DatabaseException(lang('Database.failGetForeignKeyData'));
+        }
+        $query = $query->getResultObject();
+
+        $retVal = [];
+
+        foreach ($query as $row) {
+            $obj                      = new stdClass();
+            $obj->constraint_name     = $row->CONSTRAINT_NAME;
+            $obj->table_name          = $row->TABLE_NAME;
+            $obj->column_name         = $row->COLUMN_NAME;
+            $obj->foreign_table_name  = $row->REFERENCED_TABLE_NAME;
+            $obj->foreign_column_name = $row->REFERENCED_COLUMN_NAME;
+
+            $retVal[] = $obj;
+        }
+
+        return $retVal;
+    }
+
+    /**
+     * Returns platform-specific SQL to disable foreign key checks.
+     *
+     * @return string
+     */
+    protected function _disableForeignKeyChecks()
+    {
+        return 'SET FOREIGN_KEY_CHECKS=0';
+    }
+
+    /**
+     * Returns platform-specific SQL to enable foreign key checks.
+     *
+     * @return string
+     */
+    protected function _enableForeignKeyChecks()
+    {
+        return 'SET FOREIGN_KEY_CHECKS=1';
+    }
+
+    /**
+     * Returns the last error code and message.
+     * Must return this format: ['code' => string|int, 'message' => string]
+     * intval(code) === 0 means "no error".
+     *
+     * @return array<string, int|string>
+     */
+    public function error(): array
+    {
+        if (! empty($this->mysqli->connect_errno)) {
+            return [
+                'code'    => $this->mysqli->connect_errno,
+                'message' => $this->mysqli->connect_error,
+            ];
+        }
+
+        return [
+            'code'    => $this->connID->errno,
+            'message' => $this->connID->error,
+        ];
+    }
+
+    /**
+     * Insert ID
+     */
+    public function insertID(): int
+    {
+        return $this->connID->insert_id;
+    }
+
+    /**
+     * Begin Transaction
+     */
+    protected function _transBegin(): bool
+    {
+        $this->connID->autocommit(false);
+
+        return $this->connID->begin_transaction();
+    }
+
+    /**
+     * Commit Transaction
+     */
+    protected function _transCommit(): bool
+    {
+        if ($this->connID->commit()) {
+            $this->connID->autocommit(true);
+
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Rollback Transaction
+     */
+    protected function _transRollback(): bool
+    {
+        if ($this->connID->rollback()) {
+            $this->connID->autocommit(true);
+
+            return true;
+        }
+
+        return false;
+    }
+}

system/Database/MySQLi/Forge.php

@@ -0,0 +1,239 @@
+<?php
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\Database\MySQLi;
+
+use CodeIgniter\Database\Forge as BaseForge;
+
+/**
+ * Forge for MySQLi
+ */
+class Forge extends BaseForge
+{
+    /**
+     * CREATE DATABASE statement
+     *
+     * @var string
+     */
+    protected $createDatabaseStr = 'CREATE DATABASE %s CHARACTER SET %s COLLATE %s';
+
+    /**
+     * CREATE DATABASE IF statement
+     *
+     * @var string
+     */
+    protected $createDatabaseIfStr = 'CREATE DATABASE IF NOT EXISTS %s CHARACTER SET %s COLLATE %s';
+
+    /**
+     * DROP CONSTRAINT statement
+     *
+     * @var string
+     */
+    protected $dropConstraintStr = 'ALTER TABLE %s DROP FOREIGN KEY %s';
+
+    /**
+     * CREATE TABLE keys flag
+     *
+     * Whether table keys are created from within the
+     * CREATE TABLE statement.
+     *
+     * @var bool
+     */
+    protected $createTableKeys = true;
+
+    /**
+     * UNSIGNED support
+     *
+     * @var array
+     */
+    protected $_unsigned = [
+        'TINYINT',
+        'SMALLINT',
+        'MEDIUMINT',
+        'INT',
+        'INTEGER',
+        'BIGINT',
+        'REAL',
+        'DOUBLE',
+        'DOUBLE PRECISION',
+        'FLOAT',
+        'DECIMAL',
+        'NUMERIC',
+    ];
+
+    /**
+     * Table Options list which required to be quoted
+     *
+     * @var array
+     */
+    protected $_quoted_table_options = [
+        'COMMENT',
+        'COMPRESSION',
+        'CONNECTION',
+        'DATA DIRECTORY',
+        'INDEX DIRECTORY',
+        'ENCRYPTION',
+        'PASSWORD',
+    ];
+
+    /**
+     * NULL value representation in CREATE/ALTER TABLE statements
+     *
+     * @var string
+     *
+     * @internal
+     */
+    protected $null = 'NULL';
+
+    /**
+     * CREATE TABLE attributes
+     *
+     * @param array $attributes Associative array of table attributes
+     */
+    protected function _createTableAttributes(array $attributes): string
+    {
+        $sql = '';
+
+        foreach (array_keys($attributes) as $key) {
+            if (is_string($key)) {
+                $sql .= ' ' . strtoupper($key) . ' = ';
+
+                if (in_array(strtoupper($key), $this->_quoted_table_options, true)) {
+                    $sql .= $this->db->escape($attributes[$key]);
+                } else {
+                    $sql .= $this->db->escapeString($attributes[$key]);
+                }
+            }
+        }
+
+        if (! empty($this->db->charset) && ! strpos($sql, 'CHARACTER SET') && ! strpos($sql, 'CHARSET')) {
+            $sql .= ' DEFAULT CHARACTER SET = ' . $this->db->escapeString($this->db->charset);
+        }
+
+        if (! empty($this->db->DBCollat) && ! strpos($sql, 'COLLATE')) {
+            $sql .= ' COLLATE = ' . $this->db->escapeString($this->db->DBCollat);
+        }
+
+        return $sql;
+    }
+
+    /**
+     * ALTER TABLE
+     *
+     * @param string $alterType ALTER type
+     * @param string $table     Table name
+     * @param mixed  $field     Column definition
+     *
+     * @return string|string[]
+     */
+    protected function _alterTable(string $alterType, string $table, $field)
+    {
+        if ($alterType === 'DROP') {
+            return parent::_alterTable($alterType, $table, $field);
+        }
+
+        $sql = 'ALTER TABLE ' . $this->db->escapeIdentifiers($table);
+
+        foreach ($field as $i => $data) {
+            if ($data['_literal'] !== false) {
+                $field[$i] = ($alterType === 'ADD') ? "\n\tADD " . $data['_literal'] : "\n\tMODIFY " . $data['_literal'];
+            } else {
+                if ($alterType === 'ADD') {
+                    $field[$i]['_literal'] = "\n\tADD ";
+                } else {
+                    $field[$i]['_literal'] = empty($data['new_name']) ? "\n\tMODIFY " : "\n\tCHANGE ";
+                }
+
+                $field[$i] = $field[$i]['_literal'] . $this->_processColumn($field[$i]);
+            }
+        }
+
+        return [$sql . implode(',', $field)];
+    }
+
+    /**
+     * Process column
+     */
+    protected function _processColumn(array $field): string
+    {
+        $extraClause = isset($field['after']) ? ' AFTER ' . $this->db->escapeIdentifiers($field['after']) : '';
+
+        if (empty($extraClause) && isset($field['first']) && $field['first'] === true) {
+            $extraClause = ' FIRST';
+        }
+
+        return $this->db->escapeIdentifiers($field['name'])
+                . (empty($field['new_name']) ? '' : ' ' . $this->db->escapeIdentifiers($field['new_name']))
+                . ' ' . $field['type'] . $field['length']
+                . $field['unsigned']
+                . $field['null']
+                . $field['default']
+                . $field['auto_increment']
+                . $field['unique']
+                . (empty($field['comment']) ? '' : ' COMMENT ' . $field['comment'])
+                . $extraClause;
+    }
+
+    /**
+     * Process indexes
+     *
+     * @param string $table (ignored)
+     */
+    protected function _processIndexes(string $table): string
+    {
+        $sql = '';
+
+        for ($i = 0, $c = count($this->keys); $i < $c; $i++) {
+            if (is_array($this->keys[$i])) {
+                for ($i2 = 0, $c2 = count($this->keys[$i]); $i2 < $c2; $i2++) {
+                    if (! isset($this->fields[$this->keys[$i][$i2]])) {
+                        unset($this->keys[$i][$i2]);
+
+                        continue;
+                    }
+                }
+            } elseif (! isset($this->fields[$this->keys[$i]])) {
+                unset($this->keys[$i]);
+
+                continue;
+            }
+
+            if (! is_array($this->keys[$i])) {
+                $this->keys[$i] = [$this->keys[$i]];
+            }
+
+            $unique = in_array($i, $this->uniqueKeys, true) ? 'UNIQUE ' : '';
+
+            $sql .= ",\n\t{$unique}KEY " . $this->db->escapeIdentifiers(implode('_', $this->keys[$i]))
+                . ' (' . implode(', ', $this->db->escapeIdentifiers($this->keys[$i])) . ')';
+        }
+
+        $this->keys = [];
+
+        return $sql;
+    }
+
+    /**
+     * Drop Key
+     *
+     * @return bool
+     */
+    public function dropKey(string $table, string $keyName)
+    {
+        $sql = sprintf(
+            $this->dropIndexStr,
+            $this->db->escapeIdentifiers($keyName),
+            $this->db->escapeIdentifiers($this->db->DBPrefix . $table),
+        );
+
+        return $this->db->query($sql);
+    }
+}

system/Database/MySQLi/PreparedQuery.php

@@ -0,0 +1,87 @@
+<?php
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\Database\MySQLi;
+
+use BadMethodCallException;
+use CodeIgniter\Database\BasePreparedQuery;
+
+/**
+ * Prepared query for MySQLi
+ */
+class PreparedQuery extends BasePreparedQuery
+{
+    /**
+     * Prepares the query against the database, and saves the connection
+     * info necessary to execute the query later.
+     *
+     * NOTE: This version is based on SQL code. Child classes should
+     * override this method.
+     *
+     * @param array $options Passed to the connection's prepare statement.
+     *                       Unused in the MySQLi driver.
+     *
+     * @return mixed
+     */
+    public function _prepare(string $sql, array $options = [])
+    {
+        // Mysqli driver doesn't like statements
+        // with terminating semicolons.
+        $sql = rtrim($sql, ';');
+
+        if (! $this->statement = $this->db->mysqli->prepare($sql)) {
+            $this->errorCode   = $this->db->mysqli->errno;
+            $this->errorString = $this->db->mysqli->error;
+        }
+
+        return $this;
+    }
+
+    /**
+     * Takes a new set of data and runs it against the currently
+     * prepared query. Upon success, will return a Results object.
+     */
+    public function _execute(array $data): bool
+    {
+        if (! isset($this->statement)) {
+            throw new BadMethodCallException('You must call prepare before trying to execute a prepared statement.');
+        }
+
+        // First off -bind the parameters
+        $bindTypes = '';
+
+        // Determine the type string
+        foreach ($data as $item) {
+            if (is_int($item)) {
+                $bindTypes .= 'i';
+            } elseif (is_numeric($item)) {
+                $bindTypes .= 'd';
+            } else {
+                $bindTypes .= 's';
+            }
+        }
+
+        // Bind it
+        $this->statement->bind_param($bindTypes, ...$data);
+
+        return $this->statement->execute();
+    }
+
+    /**
+     * Returns the result object for the prepared query.
+     *
+     * @return mixed
+     */
+    public function _getResult()
+    {
+        return $this->statement->get_result();
+    }
+}

system/Database/MySQLi/Result.php

@@ -0,0 +1,162 @@
+<?php
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\Database\MySQLi;
+
+use CodeIgniter\Database\BaseResult;
+use CodeIgniter\Entity\Entity;
+use stdClass;
+
+/**
+ * Result for MySQLi
+ */
+class Result extends BaseResult
+{
+    /**
+     * Gets the number of fields in the result set.
+     */
+    public function getFieldCount(): int
+    {
+        return $this->resultID->field_count;
+    }
+
+    /**
+     * Generates an array of column names in the result set.
+     */
+    public function getFieldNames(): array
+    {
+        $fieldNames = [];
+        $this->resultID->field_seek(0);
+
+        while ($field = $this->resultID->fetch_field()) {
+            $fieldNames[] = $field->name;
+        }
+
+        return $fieldNames;
+    }
+
+    /**
+     * Generates an array of objects representing field meta-data.
+     */
+    public function getFieldData(): array
+    {
+        static $dataTypes = [
+            MYSQLI_TYPE_DECIMAL    => 'decimal',
+            MYSQLI_TYPE_NEWDECIMAL => 'newdecimal',
+            MYSQLI_TYPE_FLOAT      => 'float',
+            MYSQLI_TYPE_DOUBLE     => 'double',
+
+            MYSQLI_TYPE_BIT      => 'bit',
+            MYSQLI_TYPE_SHORT    => 'short',
+            MYSQLI_TYPE_LONG     => 'long',
+            MYSQLI_TYPE_LONGLONG => 'longlong',
+            MYSQLI_TYPE_INT24    => 'int24',
+
+            MYSQLI_TYPE_YEAR => 'year',
+
+            MYSQLI_TYPE_TIMESTAMP => 'timestamp',
+            MYSQLI_TYPE_DATE      => 'date',
+            MYSQLI_TYPE_TIME      => 'time',
+            MYSQLI_TYPE_DATETIME  => 'datetime',
+            MYSQLI_TYPE_NEWDATE   => 'newdate',
+
+            MYSQLI_TYPE_SET => 'set',
+
+            MYSQLI_TYPE_VAR_STRING => 'var_string',
+            MYSQLI_TYPE_STRING     => 'string',
+
+            MYSQLI_TYPE_GEOMETRY    => 'geometry',
+            MYSQLI_TYPE_TINY_BLOB   => 'tiny_blob',
+            MYSQLI_TYPE_MEDIUM_BLOB => 'medium_blob',
+            MYSQLI_TYPE_LONG_BLOB   => 'long_blob',
+            MYSQLI_TYPE_BLOB        => 'blob',
+        ];
+
+        $retVal    = [];
+        $fieldData = $this->resultID->fetch_fields();
+
+        foreach ($fieldData as $i => $data) {
+            $retVal[$i]              = new stdClass();
+            $retVal[$i]->name        = $data->name;
+            $retVal[$i]->type        = $data->type;
+            $retVal[$i]->type_name   = in_array($data->type, [1, 247], true) ? 'char' : ($dataTypes[$data->type] ?? null);
+            $retVal[$i]->max_length  = $data->max_length;
+            $retVal[$i]->primary_key = $data->flags & 2;
+            $retVal[$i]->length      = $data->length;
+            $retVal[$i]->default     = $data->def;
+        }
+
+        return $retVal;
+    }
+
+    /**
+     * Frees the current result.
+     */
+    public function freeResult()
+    {
+        if (is_object($this->resultID)) {
+            $this->resultID->free();
+            $this->resultID = false;
+        }
+    }
+
+    /**
+     * Moves the internal pointer to the desired offset. This is called
+     * internally before fetching results to make sure the result set
+     * starts at zero.
+     *
+     * @return mixed
+     */
+    public function dataSeek(int $n = 0)
+    {
+        return $this->resultID->data_seek($n);
+    }
+
+    /**
+     * Returns the result set as an array.
+     *
+     * Overridden by driver classes.
+     *
+     * @return mixed
+     */
+    protected function fetchAssoc()
+    {
+        return $this->resultID->fetch_assoc();
+    }
+
+    /**
+     * Returns the result set as an object.
+     *
+     * Overridden by child classes.
+     *
+     * @return bool|Entity|object
+     */
+    protected function fetchObject(string $className = 'stdClass')
+    {
+        if (is_subclass_of($className, Entity::class)) {
+            return empty($data = $this->fetchAssoc()) ? false : (new $className())->setAttributes($data);
+        }
+
+        return $this->resultID->fetch_object($className);
+    }
+
+    /**
+     * Returns the number of rows in the resultID (i.e., mysqli_result object)
+     */
+    public function getNumRows(): int
+    {
+        if (! is_int($this->numRows)) {
+            $this->numRows = $this->resultID->num_rows;
+        }
+
+        return $this->numRows;
+    }
+}

system/Database/MySQLi/Utils.php

@@ -0,0 +1,45 @@
+<?php
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\Database\MySQLi;
+
+use CodeIgniter\Database\BaseUtils;
+use CodeIgniter\Database\Exceptions\DatabaseException;
+
+/**
+ * Utils for MySQLi
+ */
+class Utils extends BaseUtils
+{
+    /**
+     * List databases statement
+     *
+     * @var string
+     */
+    protected $listDatabases = 'SHOW DATABASES';
+
+    /**
+     * OPTIMIZE TABLE statement
+     *
+     * @var string
+     */
+    protected $optimizeTable = 'OPTIMIZE TABLE %s';
+
+    /**
+     * Platform dependent version of the backup function.
+     *
+     * @return mixed
+     */
+    public function _backup(?array $prefs = null)
+    {
+        throw new DatabaseException('Unsupported feature of the database platform you are using.');
+    }
+}