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1 multi meter 1.1 multi table description In actual development, a project usually needs many tables to complete For example, the database of a shopping mall project needs many tables: user table, classification table, commodity table, order table 1.2 disadvantages of single table 1.2.1 table building C ...

[1] The difference between int(3) and int(11) (cognitive error of thinking inertia) Here, 3 or 11 represents the specific length stored in the database, always thinking that int(3) can only store 3 numbers of length, and int(11) can only store 11 numbers of length. [2] Mysql Basics When learning M ...

originate stackoverflow Last question Why it is faster to deal with an ordered array than to deal with an array without it , there are some discussions in the original text. Let's first reproduce the results and then explain why! We have the following two sections of code. The code looks similar, but in fact, the logic is the same. They count t ...

Shortest palindrome string Given a string s, you can convert it to a palindrome string by adding characters before the string. Find and return the shortest palindrome string that can be converted in this way. You can use horse drawn cart to get the longest palindrome substring, and then add it in reve ...

Previously introduced Detailed usage of matplotlib plot method , today we will introduce the drawing method in pandas. In essence, the drawing method encapsulated in pandas calls the drawing method of matplotlib. The basic plot method, the plot method of Series and DataFrame in pandas, is the plot ...

There are many tutorials about SPI. Here is a summary of my study of SPI protocol. What is SPI? SPI is the abbreviation of Serial Peripheral Interface Bus, which means serial peripheral interface. It is a synchronous serial communication interface standard for short distance communication, mainly used in embedded system. This in ...

k8s uses Nodeport to expose services There are many ways to expose K8s services. Here we mainly study how to expose services through Nodeport First of all, we must understand several concepts before exposing ports: *< 1 >. Server: it is a cluster instance entry composed of accessing backend pod replicas. It consists of: ` [cluster_ip] ` ...

HTML Notes File extension Word.docx Excel.xlsx PPT.pptx How to open a file extension: [External chain picture transfer failed, source station may have anti-theft chain mechanism, it is recommended to save pictures and upload them directly (img-Vty2rmPe-15928773052) (D:Static Web Page MakingNotesNote ...

1. Student management system (completed after class) 1.1 modification //modify private static void updateStudent(ArrayList<Student> list) { //Create keyboard entry object Scanner sc = new Scanner(System.in); System.out.println("Please enter the number of the studen ...

Introduction to String class String yes a reference data type is null by default;String is of final type and cannot be changed and inherited;The combination of basic type and String will be converted to String type; 1, String common methods length() method 1. Use the length() method of the String class to get the length of the declared String o ...