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Before, ID was implemented with auto increment. Now I want to use Snowflake algorithm to generate primary key. What changes should I make? catalog Background Implementation plan Scenario 1 - add primary key manually Scenario 2 - override save() method Scenario 3 - using pre in Django Signals_ save() ...

A few days ago, a group member of the technical group asked a question about the thread pool, as shown in the figure: So let's talk about this. In a thread pool, threads read tasks from workQueue to execute. The smallest unit of execution is Worker, which implements the Runnable interface and overrides the run method.The method is to let eac ...

HTML 1, html introduction 1. What is HTML? HTML:hyper text Makrup language hypertext markup language is composed of various tags, which are used to make web pages and tell browsers how to display pages 2. Function Make web pages, control the display of web pages and content Insert picture, musi ...

Opening I believe that little partners know more or less about these two words. They are common thread communication tools in concurrent programming. The two are very similar, but they are different, which leads to a lot of confusion among many small partners, including me: what is the difference between them, and what scenarios are they applic ...

1445: Flat Painting Time limit: 1000 ms memory limit: 65536 KB Number of submissions: 565 passes: 296 [Title Description] CE Digital has developed a product called Automatic Color Machine (APM).It can use predefined colors to color a flat panel of rectangles of different sizes that do not cover each oth ...

Article catalog Thread synchronizer in Java Concurrent package (CountDownLatch, CyclicBarrier and Semaphore) CountDownLatch Core method 1: countDown Core method 2: await Core method 3: getCount CyclicBarrier Core method 1: await Core method 2: reset Semaphore Core method 1: construction Core me ...

Articles have been included in Github.com/niumoo/JavaNotes Welcome to Star and Instructions. Welcome to my attention Public Number , articles are updated weekly. The previous article introduced the HashMap source code, which was very popular. Many students expressed their opinions. This time it came again. This time it is ConcurrentHashMap. A ...

1, Why open slow query Most of the reasons for the poor query performance are the large amount of data. To start the slow query of mysql and record the SQL statements that take a long time to query in the log is conducive to our better position and optimization. 2, Several common reasons for the ...

Title: As we all know, TT has a magic meow at home. This meow is very sleepy. There is no day or night when you sleep. Meow meow can sleep many times a day!! Sleep as long as you want Meow sleep time is continuous, that is, once meow starts to sleep, it can not be disturbed, otherwise meow will bite peo ...

Reprint website: http://blog.csdn.net/sinat_29912455/article/details/51137349 Sword finger Offer (java answer) Sword point Offerjava answer 3 search in 2D array 4 replace space 5 print the linked list from the ...