JDBC operation data and DAO design pattern in actual combat
Using JDBC to manipulate data
1. Using JDBC to write large text data to the database
Purpose: to java and other text files are written to the corresponding fields of the corresponding table by connecting the database with JDBC.
1. Table structure
2. Documents
3. Implementation code for inserting text
package LoadFileTest;
import driver.JDB ...
Posted by schoi on Wed, 25 May 2022 18:54:45 +0300
MySql advanced master-slave synchronization ☆
Master slave synchronization of MySql advanced
1. Replication overview
This means that the master and slave databases can be synchronized again by transferring these data to the master and slave databases through the DDL.
MySQL supports the replication of one master database to multiple slave databases at the same time. The slave database ca ...
Posted by upit on Wed, 25 May 2022 17:55:35 +0300
MySQL 8.0 window function ranking and topN problems
MySQL 8.0 window function ranking and topN problems
I've been using mysql5 7. Unexpectedly, a very useful function - window function is added to 8.0. Here, the window function, its usage and problems that can be solved are summarized as follows
what
Window function --- also known as OLAP function --- online analytical processing
The window fu ...
Posted by fazlionline on Mon, 23 May 2022 10:10:26 +0300
Filters, listeners and mysql
review
EL
Syntax ${expression}
EL domain objects, and lookup rules
pageScope
requestScope
sessionScope
applicationScope
What is the function of pageContext object in EL
You can get other objects
${ pageContext.request.contextPath }
How does EL display the attributes of students, elements in list and elements in map
${Student object. Pro ...
Posted by konqest on Mon, 23 May 2022 01:54:54 +0300
centos7 quick guide for building MySQL NDB Cluster 7.5/7.6 cluster
NDB Cluster is a technology that enables in memory database clustering in a shareless system. Shareless architecture enables the system to use very cheap hardware with minimal specific requirements for hardware or software.
NDB Cluster is designed without any single point of failure. In a non shared system, each component should have its own m ...
Posted by DrTom on Sun, 22 May 2022 08:32:09 +0300
MySQL Optimization -- IO scheduling algorithm optimization
Previously, we have shared the database optimization method on wechat official account. The link is https://mp.weixin.qq.com/s/6Atzk9UKPJRxxAs0nsKBXg . The operating system part introduces the optimization of IO scheduling algorithm. This paper will compare the performance of disk IO under different scheduling algorithms through stress ...
Posted by Lashiec on Sat, 21 May 2022 20:13:33 +0300
MySQL tutorial 83-INSERT insert data (add data)
After the database and table are created successfully, you need to insert data into the table of the database. In MySQL You can use the INSERT statement to INSERT one or more rows of tuple data into the existing tables in the database.
Basic grammar
The INSERT statement has two syntax forms: INSERT... VALUES statement and INSERT... SET statemen ...
Posted by fothers on Sat, 21 May 2022 16:49:24 +0300
MySQL tutorial 105 MySQL modifying stored procedures
In the actual development process, business requirements are modified from time to time, so they are modified MySQL Stored procedures in are inevitable.
Modify stored procedures through ALTER PROCEDURE statement in MySQL. The method of modifying stored procedures will be explained in detail here.
The syntax format of modifying stored procedures ...
Posted by slapdashgrim on Sat, 21 May 2022 09:09:13 +0300
Big data - MySQL system information function
1. Function to obtain MySQL version number, number of connections and database name
(1)version()
version() returns a string indicating the MySQL server version, which uses the utf8 character set.
[example] check the current MySQL version number. The SQL statement is as follows:
mysql> select version();
+-----------+
| version() |
+-------- ...
Posted by galvin on Sat, 21 May 2022 07:51:54 +0300
Mysql database 2: DML operation, multi table relationship and query operation
catalogue
1. DML - modify operation
2. DML delete
3. Mysql simple query operation
4. Multi table relationship and table building principle
4. Mysql multi table Association query
4.1 mysql Association query classification
4.2 write sql statement to realize mysql multi table Association query
5. Mysql query operation
1. DM ...
Posted by drag0n on Fri, 20 May 2022 23:14:59 +0300