• Learning record of mongodb master class (day 10)


    Record of pits Maybe there is a problem with the previous understanding. I looked at the official document yesterday. You can install it directly through brewMongoDB CommunityThe latest version of. Of course, there is no way to use the enterprise version. You have to download the compressed package and configure it yourself. setup script Environment […]

  • JavaScript double linked list


    JavaScript double linked list A double linked list(doubly linked list)A linked data structure consists of a set of sequential linked records called nodes. Each node contains two fields, called links, which are references to the previous and next nodes in the node sequence The previous link and the next link of the start node and […]

  • Search algorithm (1) — sequential search — sequential search


    1. Sequence search (1) descriptionSequential lookup is suitable for linear tables whose storage structure is sequential storage or linked storage.(2) basic ideasSequential search, also known as linear search, belongs to the unordered search algorithm. Starting from one end of the data structure linear table, scan in sequence, and compare the scanned node keywords with the […]

  • SAP IDoc generates sales order through Po output message


    Inscription: On the Internet, I saw a similar official account, called “PO&SO integration gradually guided by IDoc”. I feel that the whole configuration process is still missing some key configuration and the core logic of the whole function is missing. Let me give a full explanation of this opportunity.   Business description: This function is […]

  • Grid grid common layout


    There is no gap on both sides, and there is gap between each column width: 100%; display: grid; grid-template-columns: repeat(4,1fr); justify-items: stretch; grid-gap: 1px; Property Description:justify-itemsProperty to set the horizontal position (left, center, right) of the cell content,align-itemsProperty to set the vertical position (top, middle, and bottom) of the cell contents. Start: aligns the start […]

  • Learning record of mongodb Master Course (day 17)


    Written in front Recently, there are new projects online, which is too busy. The progress of learning is a little slow, but I will stick to it. Seventeenth days Today I want to learn the chapter “20 transaction development: read one of the operational transactions”. It mainly explains how to read data. Readrreference parameter There […]

  • Common tools for analysts SQL (common syntax and common window functions)


    1 – execution sequencefrom-on-join-where-group by-having-select-distinct-order by-limit From (the Cartesian product is calculated for the tables on the left and right sides of from to get the virtual table V1)On (filter V1 table to get V2)Join (carry out left join, right join and other processing on V2 table to get V3)Where (where filter V3 to get […]

  • SAP mm of “SAP Technology” clearly has a list of maintenance sources, or can’t issue PO?


    SAP mm clearly has a list of maintenance sources, or can’t issue PO?     In the afternoon, the user reported an error that failed to create the purchase order. The error was: material not included in source list desired source list requirement. As shown in the following figure:     In fact, the source […]

  • CSS (3) BFC and cascading context


    This article mainly introduces the knowledge of BFC and cascading context. Block format context (BFC) 1、 Definition of BFC  BFC (block formatting context): is an independent rendering area, the layout of the elements inside the box will not affect the outside of the box. It belongs toOrdinary flow。 2、 Those methods create a block formatting context   […]

  • JavaScript self study notes (2) — the difference between function a() {} and var a = function() {} (JavaScript)


    The difference between function a() {} and var a = function() {}:   Learn to make floating windows, and see that others’ codes include: window.onresize = function(){ Chrox = document.documentelement.clientwidth; // whole height and width of YeMian chroY = document.documentElement.clientHeight; } After reading it, I didn’t understand it very much, so I went to check […]

  • (network learning) 1. Message queue summary


    Application scenario https://www.imooc.com/video/15163 Redundancy: delay processing and guarantee completion Decoupling: access decoupling Traffic peak cancellation: redis cache Asynchronous communication: asynchronous scenario Convenient extension: the result of decoupling Sequencing guarantee: sequencing 1. MySQL lock queue —Order system [manufacturer]–Receive order, core code: //Save order information to order form $db = DB::getIntance(); $res = $db->insert(“order_queue”, $insert_data); –Distribution system […]

  • Asynchronous operation processing of multiple sequential requirements in Vue


    Recently, there is a demand in the project business that users can place orders in batches, but each order has a price protection fee. The handling fee needs to be calculated by the background model according to the value of the order, and then each order needs to bring this price protection fee when placing […]