Preparation Before we begin, we need to ensure that we have a Python environment installed and a basic understanding of Python syntax. Additionally, we need a log file as sample data. Here, we assume the log file is formatted as one log entry per line, with each entry containing a timestamp, log level, module name, … Read more
I. Reasons for using transactions In many cases, we need to execute a set of operations that either all fail or all succeed. For example, in a bank transfer, one user transfers money to another, deducting funds from the first user’s account and increasing the second user’s balance. Imagine if the MySQL server crashes after … Read more
I. Basic Queries: Retrieving Data from Tables 1.1 Syntax Format 1.2 Practical Examples Assuming a table named `student` exists, containing fields `id`, `name`, `sex`, `age`, and `class_num`, a basic query is demonstrated: # Query all fields (* represents all fields) SELECT * FROM student; # Query specific fields (name, sex) SELECT name, sex FROM student; … Read more
I. Gateway 1. Nginx (Traffic Gateway) 2. Gateway (Business Gateway) 3. API Gateway Relationship summary: There are also mutual calls between the business gateway, API gateway, and microservices: Follow the five-tuple : source IP, source port, destination IP, destination port, protocol II. The Relationship Between DNS, Domain Names, and IP Addresses An IP address is a device’s “unique ID … Read more
Core Process Overview In Spring Boot applications, we typically write a class containing a main method and call `SpringApplication.run`.Example code: The entire startup process can be summarized as: constructing SpringApplication an object -> executing run a method -> starting the embedded server -> completing application startup . Phase 1: SpringApplication Instantiation Execution method:new SpringApplication(primarySources) At this point, SpringApplication the object has been constructed, and its … Read more
1. Built-in class Numeric types: int (integer), float (floating-point number), complex (complex number); Sequence types: list, tuple, str, bytes (byte sequence), bytearray (mutable byte sequence), memoryview (memory view); Collection types: set (mutable collection), frozenset (immutable collection); Mapping type: dict (dictionary); Other: bool (a subclass of int), NoneType (accessed via type(None)). 2. Built-in methods Built-in methods in Python are typically methods … Read more
I. Introduction RxJava is a reactive programming framework developed by Netflix based on the Java Virtual Machine . It belongs to the ReactiveX open-source project and aims to simplify the development process of asynchronous programming and event-driven programs. This framework extends the observer pattern to support the composition of observable objects for processing data streams and … Read more
1. Train a classifier using the CIFAR10 dataset. 1.1 Importing Packages The output of the torchvision dataset is PILImage images in the range [0, 1]. These are then converted to Tensors with a normalized range of [-1, 1]. 1.2 Loading Data Load and preprocess the CIFAR-10 dataset, create data loaders for training and testing, and … Read more
During Vue 3 composable API development, the following TypeScript errors are frequently encountered: The `emit(‘orderSubmit’)` function should have two arguments, but it only returns one. This error typically occurs when using <script setup> syntactic sugar, especially when defineEmits defining and invoking custom events. Typical error scenarios II. In-depth analysis of the root causes of the problem 2.1 Analysis of … Read more
01 Deconstruction: The Underlying Structure of the Interface The interface can flexibly adapt to different types, which stems from the “dual-column storage” logic of its underlying design. However, there are key differences in the structure between empty and non-empty interfaces, which is the basis for understanding the characteristics of the interface. 1.1 Empty Interface (eface): … Read more