What is Mybatis?
MyBatis is an excellent persistence layer framework.It supports custom SQL, stored procedures, and advanced mapping.MyBatis eliminates almost all JDBC code and the work of setting parameters and obtaining result sets.MyBatis can configure and map primitive types, interfaces and Java POJO s (Plain Old Java O ...
Posted by ClyssaN on Wed, 22 Sep 2021 15:44:35 +0200
Introduction to Codis
Codis is a distributed Redis solution. For upper tier applications, there is no obvious difference between connecting to the Codis Proxy and connecting to the native Redis Server (unsupported command list). Upper tier applications can be used like stand-alone Redis. The lower tier of Codis will handle r ...
Posted by rulinus on Wed, 22 Sep 2021 15:26:29 +0200
1 Overview2 example description
2.1 flashback query2.2 flashback version query2.3 flashback transaction query2.4 flashback table2.5 flashback deletion 3 expansion
In order to recover Oracle database from misoperation quickly, Oracle has introduced flashback technology.This blog mainly shares the flashbac ...
Posted by Taneya on Wed, 22 Sep 2021 02:16:23 +0200
1, Singleton mode
2: Factory mode
3, Abstract factory pattern
5, Reference website
1, Singleton mode
1. Usage scenario of singleton mode in real life:
Background processing services for printers
Log object for the application
Connection pool for database
Counters for web sites
Configuration object fo ...
Posted by Jaspal on Tue, 21 Sep 2021 07:00:21 +0200
What is singleton mode
Definition of Singleton pattern: a pattern in which a class has only one instance and the class can create the instance itself.
For example, only one task manager can be opened in Windows, which can avoid the waste of memory resources caused by opening multiple task manager Windows, or errors such ...
Posted by magic003 on Tue, 21 Sep 2021 05:14:53 +0200
The difference between a view and a table: "Is the actual data saved?""Views are not tables. Views are virtual tables. Views depend on tables."
1.1 Create View
CREATE VIEW <View Name>(<Column Name 1>,<Column Name 2>,...) AS <SELECT Sentence>
-- Create views based on multiple tables wit ...
Posted by optikalefx on Mon, 20 Sep 2021 17:36:37 +0200
High performance server, network theoretical knowledge and operating system
High performance server
Improve server performance
1. I/O model
Blocking IO (not appropriate)
Program blocking and read / write function when there is no data to read, the program blocks until the data is read successfully
Blocking process: the time period whe ...
Posted by mattpointblank on Mon, 20 Sep 2021 15:30:51 +0200
1.1 arithmetic operators
1.2 comparison operators
operatormeaning=Equal to<>And ~ are not equal>=Greater than or equal to>greater than<=Less than or equal to<less than
2 exercise part 1 - query
2.1 writing the product table
The SQL code is as foll ...
Posted by jzimmerlin on Mon, 20 Sep 2021 03:45:43 +0200
1. sql Title Brushing
There are two main purposes to do this topic, preparing for the interview and understanding the business logic and thinking style of the data analyst in practice. Most of the data analysts are biased toward the business side, with the indicators increasing or decreasing, how to analyze, from which angles to analyze, c ...
Posted by kabucek on Mon, 20 Sep 2021 00:09:34 +0200
1. Table building syntax
Table creation belongs to DDL statements, including create, drop and alter
create table Table name (field name 1 data type, field name 2 data type, field name 3 data type,)
2. Data type
varchar: variable length string, which is slow and saves space
char: fixed length string. Regardless of the actual d ...
Posted by ravi_aptech on Sun, 19 Sep 2021 20:32:53 +0200