I had a job interview recently and I got a little homework. Then I received feedback that I had an unnecessary combination of queries and transactions in my update endpoint.
export const update = async (req: Request, res: Response, next: NextFunction) => { try { const reportId = parseInt(req.params.id) const { name, age, info } = req.body const report = await ReportModel.findOne({ where: { id: reportId } }) if (!report) return next(new EntityNotExistError("Report does not exist")) await ReportModel.update({ name, age, info }, { where: { id: reportId } }) const _report = await ReportModel.findOne({ where: { id: reportId } }) return res.json({ message: "Report edited successfully", report: _report }) } catch (error) { return next(error) } } As you can see, the first query checks if the entity exists, then I perform an update on the entity, and the last query returns the updated entity. Is there some way to optimize communication with the database?
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Your code involves three different interactions with the database for a single update operation:
ReportModel.findOne()ReportModel.update()ReportModel.findOne()Reducing database queries gets the job done and improves performance.
**Your fixed code:**
export const update = async(req: Request, res: Response, next: NextFunction) => { try { const reportId = parseInt(req.params.id); const { name, age, info } = req.body; // 执行更新并获取受影响的行数 const [numberOfAffectedRows] = await ReportModel.update({ name, age, info }, { where: { id: reportId }, // 此标志检查更新函数是否返回更新后的对象 returning: true }); // 检查实体是否被找到和更新 if (numberOfAffectedRows === 0) { return next(new EntityNotExistError("报告不存在")); } // 获取更新后的报告 const updatedReport = await ReportModel.findOne({ where: { id: reportId } }); return res.json({ message: "报告已成功编辑", report: updatedReport }); } catch (error) { return next(error); } }