Based on java web file management system

... This system development is based on B/S mode, in which the database uses MYSQL, the front page display is jsp, the development tool is eclipse, and the server adopts open source security tomcat. This paper discusses in detail the overall design idea of ​​the system, database design and...


What is the minimum requirement for programmers to enter the job? Netizen: Being able to accurately locate and paste and paste c

... For the many beginners of today's programs, the hardest thing is not to learn things, nor to clarify the logical thinking in the code, but to find the first counterpart development work. ! There are a lot of prospective programmers who have worked hard for this goal for half a year, but...


Installation of MongoDB appears Verify that you have sufficient privileges to start system services and configuration system ser

... bought this Cui Da reptile book, when the front of MongoDB installed a variety of problems! It’s really a headache! In order to have an accident in the future, first record the solution. The problem is as follows: 一, There is an article saying that the direct ignore, but after testing...


What kind of data type is the bit in the mysql database?

... Bit is called a bit data type, and its data has two values: 0 and 1, and the length is 1 bit. When you enter a value other than 0, the system treats them as one. This type of data is often used as a logical variable to indicate a binary selection of true, false or no. A type of data...


Oracle database trigger use (delete trigger)

... When we need to use the trigger, it is still very convenient, you will specify when I operate an event to trigger the effect to complete what I hope to accomplish; this is Trigger, I will give you a bunch of code, this is a when I delete the event in the operation, I hope to delete the...


v$database Switchover_Status Description

... v$database Meaning of Switchover_Status Value NOT ALLOWED The current database is not the primary database with the standby database PREPARING DICTIONARY The logical standby database is sending it to a primary database and other standby databases Redo data in order to prepare for the...


Mysql master-slave architecture when building problems

... 问题 When building Mysql master-slave architecture, I found that the Slave I/O thread has not been able to run up. Later, I checked the error and found that it was because of the main library and The Mysql UUID from the library is the same (the UUID is the same here because I am...


Reset oracle sequence starts from the specified number

... General situation We often reset the sequence when testing, the manual efficiency is relatively low, today I am resetting his code declare n number(10); V_startnum number(10):=11;--How much does it start? V_step number(10):=1;--stepping Tsql varchar2(200); V_seqname varchar2(200):='SQL...


MongoDB basic tutorial series - the second article MongoDB basic operation (a)

... 1, installation environment Download the latest version of MongoDB on the official website, download the correct MongoDB version according to its own Windows version. After downloading, double-click the 32-bit or 64-bit .msi file and follow the instructions to install it. 说明: 32-bit...


Comparison of message middleware such as Kafka, RabbitMQ, RocketMQ, etc. - Message transmission performance and difference

... Distributed system, we widely use message middleware to exchange data between systems, which is convenient for asynchronous decoupling. Now there are a lot of open source news middleware. Some time ago, our own product RocketMQ (MetaQ kernel) is also open source and get everyone's...