Programmer Think

Focus on WeChat official account [white letter], enter whitek's knowledge sharing planet. 🌍 preface Last Friday, I interviewed the third side of byte and deeply felt the importance of database knowledge. I also realized that I was weak in my usual study of database. Even after having some internship experience, I still don't have much know ...

What is a transaction 1. What is a transaction Transaction refers to a set of sql statements, in which there are multiple sql statements It may be insert, update, select or delete. We hope that these multiple sql statements can succeed or fail. The execution of these sql statements is consistent and executed as a whole. 2. When do y ...

preface 🦁 entity+Dao Model - very important Dao-Table name Dao-Add, delete, modify and query a table - it will be simplified into an interface later entity-Corresponding to the entity table in the database (table name, attribute, method) 🐅IDEA Bring your own Database JDBC Foundation (1) JDBC principle JDBC (Java Database Conne ...

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Overview of Servlet event listener In the development of relationship, it is often necessary to monitor some events, such as mouse click events and key press events. At this time, you need to use event listener. There are several important components in the listener: (1) Event: a user action (2) Event source: the object that generated the ...

I Persistence RabbitMQ supports message persistence, that is, data is written on disk. (1) exchange persistence, specifying durable = > 1 when declaring (2) queue persistence, specifying durable = > 1 when declaring (3) Message persistence, specifying delivery when delivering_ Mode = > 2 (1 is non persistent) Note: if the message is p ...

1. Plug in code analysis pageinspect is a very typical and simple plug-in. Most processes can be learned and reused. If you need to write a new plug-in, you can directly copy and modify the following two functions, and most of the framework code can be used directly. get_raw_page the classic process of reading a page get_raw_page only retur ...

Basic ideas First, explain the basic ideas. The following figure shows the location of the proxy server: From the position of the proxy server, its functions have three points Receive data from the requesterForward request to target serverForward the data of the target server to the requester Therefore, when we use Netty to build a proxy s ...

ELK log analysis 1, ELK introduction ELK platform is a complete set of centralized log processing solution, which combines ElasticSearch, Logstash and Kiabana, three open-source tools to meet the more powerful user requirements for log query, sorting and statistics. Elastic search: it is a distributed storage and retrieval engine based on L ...

preface In the previous chapter, I learned how to modify the data in the table, and I left the problem of how to modify the table in the previous chapter. The field in the data table refers to a column of the table. Each row in the data table is a record. Each record contains all the information in this row, and the field is a unit smaller ...