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Catalog Gorm update operation Update all fields Update modified fields Update selected fields No Hooks updates Batch update Update with SQL expression Modify values in Hooks Other update options Gorm update operation Update all fields Save() updates all fields of the object by default, even if you don't have an assignment. package main im ...

Introduction to L2 cache In the first level cache mentioned above, the largest sharing range is within a SqlSession. If multiple sqlsessions need to share cache, they need to use the second level cache. After the second level cache is enabled, the cachenexecutor will be used to decorate the Executor. Before entering the query process of the fir ...

1. Download and install MySQL's official Yum Repository [root@localhost ~]# wget -i -c http://dev.mysql.com/get/mysql57-community-release-el7-10.noarch.rpm Install MySQL Server root@localhost ~]# yum -y install mysql-community-server 2. MySQL database settings Start MySQL [root@localhost ~]# systemctl start mysqld.service View MySQL r ...

Now we can start to explore the core part of es: search. Search has two modes: filter and query. Filter mode is the filter mode: find the records that meet the filter conditions as the results. Query mode is divided into two steps: first filter, and then calculate the similarity of each eligible record. It's just a lot of scoring. If we want to ...

In NLP tasks, the training data is usually one sentence (Chinese or English), and each step of input sequence data is one letter. We need to preprocess the data: first use the unique heat code for these letters, and then input it into RNN. For example, the letter a represents (1, 0, 0, 0,...) , 0), the letter b is (0, 1, 0, 0 , 0). If only the ...

Today, let's have some good guys. There are some java basics in front of us, How to say also need to have some frame right, don't say much, Huang sir takes you to open dry! It's over   Spring framework 1, Spring Brief Why learn spring? Advantages of traditional projects: easy to build Disadvantages of traditional projects: ...

In the case of unconformity framework, when using jdbc to read data from the database, we have to get and set one by one, which is not only tedious but also not concise. So we write a tool class using java reflection mechanism, so it is not so troublesome to use jdbc to get data from the database. Because in many cases there is more than one p ...

Caffeine is a high-performance local cache framework based on Java 8. Its structure is basically the same as that of Guava Cache, and its api is also the same. It is basically easy to replace. Caffeine is actually based on Guava Cache, using some new features of Java 8 to improve the performance efficiency in some scenarios. In this chapter, we ...

What is safe mode In mysql, if the where condition is not added to update and delete, all data will be modified. It's not only the developers who are new to MySQL that will encounter this problem, but also the engineers who have some experience will inevitably forget to write where conditions. In order to avoid all data modification and deleti ...

1. Find the most ordered SQL SQL> SELECT HASH_VALUE, SQL_TEXT, SORTS, EXECUTIONS FROM V$SQLAREA ORDER BY SORTS DESC; 2. Find the SQL with the most reads and writes on the disk SQL> SELECT * FROM (SELECT sql_text,disk_reads "total disk" , executions "total exec",disk_reads/executions "disk/exec" FROM v$sql WHERE executions>0 and is_o ...