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preface Every time the data is backed up completely, that is, the whole database, database structure and file structure are backed up. What is saved is the database at the time when the backup is completed. It is the basis of differential backup and incremental backup. The backup and recovery operations of full backup are very simple and ...

ThreadLocal principle 1, Introduction to ThreadLocal ThreadLocal can realize that each thread has its own copy of local variables, and different threads will not interfere with each other. It mainly solves the problem of allowing each thread to bind its own value. By using the get() and set() methods, it can obtain the default value or change ...

2021SC@SDUSC In the last blog, we mentioned the RawField class except__ init__ In addition to the function, it also contains two functions: preprocess(self, x) and process(self, batch, *args, **kwargs) as the data preprocessing function and processing function. First, let's look at the preprocess function. def preprocess(self, x): ...

Title: 5 Basic Java Which of the following is the language function stored in java In the bag? () java.lang java.io java.net java.util Resolution: java.lang Package contains Packaging String class Math class —— Include function Class class Object class java.util Provide tool classes including collection fr ...

1. Data type Variable = xxx only means to point the variable to the storage space where xxx data is located. For example, a = [1,2,3] represents that the variable a points to the storage space where [1,2,3] is located. python has two data types: variable data type and immutable data type. The difference is whether the value in memory can be ...

Sword finger Offer 52. The first common node of the two linked lists Title: Enter two linked lists and find their first common node. As shown in the following two linked lists: The intersection begins at node c1. Example 1: Input: intersectVal = 8, listA = [4,1,8,4,5], listB = [5,0,1,8,4,5], skipA = 2, skipB = 3 Output: Reference of ...

1. Comparison of Redis cluster schemes Sentinel mode Before redis 3.0, the cluster is usually implemented by using sentinel tool to monitor the status of the master node. If the master node is abnormal, it will make a master-slave switch. Taking a slave as the master, the sentinel configuration is slightly complex, and the perfo ...

catalogue Eclipse common shortcuts Completion 6-6 jmu-Java-05 deletion of specified elements in set List (15 points) Referee test procedure: answer: 7-2 use of list (15 points) Input format: Output format: Input example: Output example: answer:   Eclipse common shortcuts /*  * Eclipse common shortcuts &nbs ...

objective The traditional Web front and back communication is mainly carried out by HTTP. Usually, the foreground actively requests to the background for what it needs, and the background cannot directly send data to the front. Usually, if the background data changes frequently, the foreground mainly depends on polling or long connection. ...

Oracle create table Oracle table is the core of Oracle database and the logical basis for storing data. Oracle table is a two-dimensional data structure. The data with column fields and corresponding columns constitute a data storage structure. You can simply look at a two-dimensional table in rows and columns. Columns represent Oracle columns ...