• Encapsulating websql (VII) encapsulating paging and query


    Although there are many ways of paging now, unlike before, you can only turn by page, but the basic principle is the same. The paging of websql is relatively simple (regardless of performance), because limit can be used. SQL select * from table where xxx order by xxxx limit 0,10 encapsulation /** *Paging to obtain […]

  • Seata distributed transaction failure notification


    1、 Background In our useSeataAs a distributed transaction, sometimes our distributed transaction can not succeed every time, and we need to notify these failed distributed transactions. This article briefly records how to implement notification. 2、 Function realization The email notification is simulated here, but the email is not really sent, but a log is simply […]

  • Svn solves the problem that it cannot view the recent submission log


    Phenomenon: when you show log, you can’t see the log up to a few days ago or the log of recent days. The reason is unknown. It feels like you have updated / submitted after modifying the system time resolvent:TortoiseSVN setting log caching cached repositories = > cached repositories, delete the corresponding URL record (tested […]

  • Shanghai embedded express order number recording software


    1. Company introduction Shanghai embedded Automation Technology Co., Ltd. is a professional company engaged in R & D and sales of embedded related products, automation system and information system integration. We can provide customers with embedded, Internet of things related product development, automatic production line transformation and other services, as well as a complete set […]

  • These 15 PHP interview questions can be done, and you can basically find a job


    Series articles: PHP classic interview questions, there are answers These 15 PHP interview questions can be done, and you can basically find a job 2021 this PHP interview question is well summarized and worth learning 1、FILEWhat do you mean? (5 points)The full path and file name of the file. If used in an include file, […]

  • Get the maximum and minimum records in each group Mongo vs MySQL


    Count the maximum and minimum records in each group Mongo implementation { “_id” : “01001”, “city” : “AGAWAM”, “pop” : 15338, “state” : “MA” } For complete JSON, see:http://media.mongodb.org/zips… demand Get the city with the largest population and the city with the smallest population in each state and the corresponding population db.zipcodes.aggregate( {$group: {_id:{state:”$state”,city:”$city”}, popPerCity:{$sum:”$pop”} […]

  • Do you know how database indexing works?


    Transferred from technology / translation boss – Mr. Li SONGFENGOriginal address:https://www.ituring.com.cn/article/986 Translator’s press: I accidentally searched this article (Q & A) in stackoverflow during translation today. I feel it necessary to translate it. Not only because the article itself is wonderful, but more importantly, it shows an important rule of writing articles (especially technical articles) […]

  • How to record the operation log gracefully?


    Operation logs widely exist in various b-end and some C-end systems. For example, customer service can quickly know who has done what to the work order according to the operation log of the work order, and then quickly locate the problem. The operation log is different from the system log. The operation log must be […]

  • MySQL explain field meaning


    Explain contains ID and select_ type、table、type、possible_ keys、key、key_ Len, ref, rows, extra field ID The number of the ID column is the serial number of the select. If there are several selections, there are several IDS, and the order of IDS increases in the order in which the select appears.   select_type select_ Type indicates whether […]

  • Mybatisplus multi table connection query


    Logo picture ppt backplane 16_ 9 2.001. png 1、 Preface (1) Background content The most common selection component of Dao layer in software application technology architecture is mybatis. Friends who are familiar with mybatis know how beautiful mybatis was in the past. XML files are used to solve the problem of complex database access. Today, […]

  • An example of using jsp + JavaBean + XML development


    Some examples related to JSP operation are combined with this website. The content involved in the example is part of the code of the background management end of an enterprise internal ordering system, which mainly focuses on the management of the basic information of the restaurant. The reason for the development of the example itself […]

  • Detailed explanation of database mvcc


    Original text:The most complete detailed explanation of database mvcc in the whole network. I’m responsible for the incomplete – MySQL tutorial – PHP Chinese network What is mvcc The full name is multi version concurrency control, that is, multi version concurrency control, which is mainly to improve the concurrency performance of the database. The following […]