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In mysql, a set of tables is called a database. The MySQL server manages several databases. There can be several tables under each database. Draw a diagram as follows:   Display database When we just installed MySQL, many databases and tables were built in it. We can use the following command to see which databases are available: SHOW ...

Flink execution plan level 1 - StreamTransformation The structure of list + linked list is constructed; Flink execution plan layer 2 - StreamGraph Transform the first layer into a graph structure; Next, it's time to convert StreamGraph to JobGraph. StreamGraph inherits the abstract class StreamingPlan and implements the getJobGraph method: /** ...

1. Introduction to Java data types Reference principle: The preferred description number must be int (integer) and double (decimal); For data transmission or text encoding conversion, byte type (binary processing operation) is used; The most convenient operation for processing Chinese is to use char (optional) long can be used to describe the m ...

LeetCode problem brushing - algorithm learning plan (Introduction) Title Description Introduction of ideas If the linked list is bidirectional, reversing the linked list is very simple. You only need to exchange the forward pointer and backward pointer. But now the topic specifies a single linked list, how to reverse it? In fact ...

Changes in v-model instructions There are two similar functions in vue2, sync modifier and v-model, but they are often confused in practical application because they have similar functions. For example, I want to bind a dynamic value and try to change it in the sub component. The sync modifier and v-model can realize this function, so I don't k ...

preface The essence of logistic regression mentioned in the previous blog is to find a straight line on the plane and use this straight line to segment the classification corresponding to all samples. Therefore, in most cases, logistic regression can only solve the dichotomous problem, because this straight line can only divide our plane into ...

preface This article belongs to the column "100 problems to solve Java concurrency". This column is original by the author. Please indicate the source of quotation. Please help point out the deficiencies and errors in the comment area. Thank you! Please refer to table of contents and references for this column 100 problems to sol ...

polymorphic What is polymorphism? Multiple forms and polymorphisms of the same thing in different scenarios can make the interface of functions universal. One of the three characteristics of object-oriented Advantages: clear code organization structure; Strong readability; It is conducive to early and later expansion and maintenance (based o ...

Spring Cloud Alibaba: Nacos configuration center Dynamic configuration service can manage the application configuration and service configuration of all environments in a centralized, external and dynamic way. Dynamic configuration eliminates the need to redeploy applications and services when configuration changes, making configuration manage ...

When adding objects using HashSet in Java programming, the equals method and hashCode method must be rewritten because they must comply with the characteristics of Set (no order and no repetition). First: The Set set has no order and cannot be repeated. Why: simulate a collection of reality. The repetition here is only the repetition of the ...