MyQEE\Server\Table::_createByMySQL PHP Method

    protected function _createByMySQL()
    {
        # 先检查表是否存在
        $table = $this->_link['table'];
        $sql = "SHOW TABLES LIKE `{$table}`";
        $rs = $this->_driver()->query($sql);
        $has = $rs->num_rows ? true : false;
        $rs->free();
        if ($has) {
            # 已经存在, 检查表结构
            # 读取所有数据
            $rs = $this->_driver()->query("select * from `{$table}`");
            while ($row = $rs->fetch_assoc()) {
                $key = $row['_key'];
                unset($row['_key']);
                try {
                    # 设置数据
                    parent::set($key, $row);
                } catch (\Exception $e) {
                    Server::$instance->warn($e->getMessage());
                }
            }
            unset($row);
            $rs->free();
            # 检查表结构是否变化过
            $sql = "SHOW COLUMNS FROM `{$table}`";
            $rs = $this->_driver()->query($sql);
            $col = $this->_column;
            $removedFields = [];
            $changedFields = [];
            while ($row = $rs->fetch_assoc()) {
                $field = $row['Field'];
                $oldType = $row['Type'];
                if ($field === '_key') {
                    continue;
                }
                if (isset($col[$field])) {
                    # 此字段在字段设置里存在
                    list($newType, $newSize) = $col[$field];
                    $fieldChanged = false;
                    if ($oldType === 'text') {
                        # 超过 2000 则为 text 类型
                        if ($newType === \Swoole\Table::TYPE_STRING && $newSize > 2000) {
                            # 相同
                        } else {
                            $fieldChanged = true;
                        }
                    } elseif (preg_match('#(varchar|bigint|int)\\((\\d+)\\)#', $oldType, $m)) {
                        # int(10), varchar(255)
                        if ($newType === \Swoole\Table::TYPE_INT) {
                            if ($newSize > 10) {
                                if ($m[1] !== 'bigint') {
                                    $fieldChanged = true;
                                }
                            } else {
                                if ($m[1] !== 'int') {
                                    $fieldChanged = true;
                                }
                            }
                        } elseif ($newType === \Swoole\Table::TYPE_FLOAT) {
                            $fieldChanged = true;
                        } else {
                            # \Swoole\Table::TYPE_STRING
                            if ($m[1] !== 'varchar' || $newSize > 2000) {
                                $fieldChanged = true;
                            }
                        }
                    } elseif (preg_match('#decimal\\((\\d+),(\\d+)\\)#', $oldType, $m)) {
                        if ($newType !== \Swoole\Table::TYPE_FLOAT) {
                            $fieldChanged = true;
                        }
                    } else {
                        $fieldChanged = true;
                    }
                    if ($fieldChanged) {
                        $changedFields[$field] = $col[$field];
                    }
                    unset($col[$field]);
                } else {
                    # 没有对应的字段, 则说明已经被删除
                    $removedFields[] = $field;
                }
            }
            if ($col || $removedFields || $changedFields) {
                # 有新增字段或移除的字段或修改的字段
                $tmp = [];
                if ($removedFields) {
                    # ALTER TABLE `adv` DROP `t`;
                    foreach ($removedFields as $field) {
                        $tmp[] = "DROP `{$col}`";
                    }
                }
                if ($changedFields) {
                    static::_mysqlBuilderFieldSQL($tmp, $changedFields, 1);
                }
                if ($col) {
                    static::_mysqlBuilderFieldSQL($tmp, $changedFields, 0);
                }
                if ($tmp) {
                    $sql = "ALTER TABLE `{$table}` " . implode(', ', $tmp);
                    Server::$instance->debug("change mysql table: {$sql}");
                    #  执行结构变更
                    $this->_driver()->query($sql);
                }
            }
        } else {
            # 不存在对应的表, 创建表格
            $tmp = [];
            static::_mysqlBuilderFieldSQL($tmp, $this->_column, 2);
            # 构造SQL
            $sql = "CREATE TABLE `{$table}` (`_key` VARCHAR(255) NOT NULL, " . implode(', ', $tmp) . ", PRIMARY KEY (`_key`)) ENGINE = InnoDB";
            Server::$instance->debug("change mysql table: {$sql}");
            $this->_driver()->query($sql);
        }
        return true;
    }