Tag：Relation
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Background combing soft deletion ideas
preface In the previous switchgear project, soft deletion was not involved at the beginning, because I was only responsible for one user management. After starting the smart community project, the problem of soft deletion has become a problem that has to be solved. Next, we will sort out the smart community project. 1. What is […]
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IOS development – realize the smooth transition effect of the navigation bar from scratch
We often encounter this problem in the project. For example, page a does not have a navigation bar, and page B has a navigation bar. If navc appears or disappears untimely when pushing from a to B or returning from B to a, the interaction will become very abrupt. The following provides a solution First, […]
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【GO】Gin
reference material[1] Basic use of gin[2] Gin awesome context[3] Introduction and use of gin framework[4] Study notes 1. Introduction Gin is a web framework written in go language. It has fast running speed, packet router, good crash capture and error handling, and very good support for middleware and JSON. In short, in the field of […]
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Python online retail data association rule mining Apriori algorithm data visualization
Original link: http://tecdat.cn/?p=23955 Association rule learningIn machine learning, it is used to find interesting relationships between variables. Apriori algorithm is a popular association rule mining and frequent itemset extraction algorithm, which is applied in association rule learning. It is designed to operate on databases containing transactions, such as purchases by store customers (basket analysis). In […]
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IOS development category
1. Describe the principle of category and why category can only add methods but not attributes? The implementation of classification is to put the methods, attributes and protocol data in category_ T structure, copy the method list in the structure to the method list of the object. Category can add attributes, but it will not […]
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Swift enumeration
AndC，Objective-CCompared with the enumeration in,SwiftinenumerationMore functionpowerful。 It supports many onlyclassUnique features, such as:Properties、Methods、Initialization、 Extensions、Protocols… Writing method of enumeration in C language Only supportIntOne type: //Week: enumeration name, which can be omitted //Mon: enumeration members //Week: define enumeration variables enum WEEK { MON, TUE, WED, THU, FRI, STA, SUN } week; Swift enumeration supportInteger、Float point、String (string)、Boolean […]
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How does spring automatically inject multiple types
There is often a small problem around me. How does spring load field characters? Why does spring support so many types such as collection, list, map, string and so on? Are there any tips worth learning in the process of spring injection? With this doubt, let’s explore it. This article is based on springboot v2 […]
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[little knowledge] querywrapper loop or condition
background The project uses mybatis plus, which needs to traverse a grid of arraysorAssociation, but other conditions outside the array areand, similar select 1 from t where a = 1 and (b like ‘%2’ or b = ‘%3’ or b = ‘%4’) solution queryWrapper.and(qw -> { for (int i = 0; i < values.length; i++) […]
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Comprehensive analysis of IOS runtime
Object-C“Message structure” is adopted instead of “function call”. The language of function call is determined by the compiler. The code executed by the language of message structure is determined by the running environment. This running environment isRuntime。 I Message mechanism 1.1. message passing The message mechanism isRuntimeThe process of method invocation can be regarded as […]
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Microservice architecture | 10.1 uses sleuth to track the service call chain
catalogue preface 1. Sleuth Basics 1.1 sleuth principle 2. Use sleuth tracking in the service 2.1 introduction of POM XML dependency file 2.2 viewing log information last preface reference material： 《Spring Microservices in Action》Principle and practice of spring cloud Alibaba microservice“Spring cloud framework development tutorial in Silicon Valley of station B” Zhou Yang Spring cloud […]
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Learn the application of SAP CDs view text association in SAP Fiori elements step by step
In the previous articleHow to add value help to fields applied by SAP Fiori elements, we have added the value help function to the selection field applied by Fiori elements through annotation. In this article, by using text association and adding agency name to ID, we will make the agent field more readable. CDs association […]
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Which is better, hibernate or mybatis
Because the programming idea is different from the design mode of database, some ORM frameworks have been born. The core is to turn relational database and data into object-oriented. Hibernate and mybatis are currently popular solutions. Both have their own advantages and disadvantages. The competition is fierce, and one of the more important considerations is […]