[Linux] dns domain name resolution service

1. DNS 1.1 Introduction to DNS Domain name resolution: (English: Domain Name System, abbreviation: DNS) is a service of the Internet. As a distributed database that maps domain names and IP addresses to each other, it can make people access the Internet more conveniently. DNS uses udp53 and tcp53. Currently,the length limit for each level […]

Skywalking process analysis_1 (main process analysis)

Foreword skywalking As the most commonly used APM monitoring at present, its importance is indescribable. I have also made many customized transformations for the company’s business. Its internal principle design is very clever, especially the custom agentClassLoader class. The loading part is even more worthy of learning from this idea. This series analyzes the internal […]

Cross-domain: Use JSONP and WebSocket to achieve cross-domain access

Cross-domain basic knowledge points: Cross-domain knowledge points Four ways for iframe to achieve cross-domain: Four ways for iframe to achieve cross-domain Note: The virtual host used in this article is also configured in the iframe above. Table of Contents JSONP cross domain Introduction to JSONP Cross-domain experiments: WebSocket cross domain Introduction to websockets Cross-domain experiments […]

Database integrity – entity integrity, referential integrity, attribute constraint naming clauses, domains

Article directory Database integrity 1. Entity integrity 1. Define entity integrity 2. Entity integrity check and breach handling 2. Referential integrity 1. Define referential integrity 2. Reference integrity check and default conditions 3. Constraints on attributes 1. Definition of constraints on attributes 2. Inspection of constraints on attributes and handling of breaches 4. Integrity constraint […]

File operations in C language (remainder)

The word count of the last blog has reached the limit, so I will add the content to this article. We still have no introduction to the determination of the end of file reading and the content of the file buffer. Let us start the next study! Table of Contents 1. Determination of the end […]