Programmer Think

0x00 Preface This article records my way of learning, directly into the body. 0x01 text Why does SQL injection occur? For me, it will be summed up as one sentence: "the SQL statement executed by dynamic splicing contains untrusted data." What is dynamic splicing? Look at the following SQL ...

qq communication group: 812321371 Wechat communication group: mercy Yao brief introduction mysql multi data source operation is often used in java projects. It is very convenient to use the original one in combination with spring boot. However, you need to configure multiple data source configurations. In microservices, the configuration of d ...

1. General query 1 SELECT the column field to be displayed FROM table name [WHERE condition]; Two cases: select userid, username from userinfo where user age < 30; 3. Query all fields: SELECT * FROM table name; 2. order by asc | desc 1 SELECT * FROM userinfo ORDER BY userage ASC; //Ascending order 2 SELECT * FROM useri ...

When Spring declarative transactions are used, it is found that abnormal transactions can be rolled back when "update" is done. However, when "insert" is executed, the background log shows that the data has been saved in the database although it is rolled back. It was originally thought that there was a configuration error, ...

Knowledge background Background reference website: https://www.cnblogs.com/luoyx/p/5896419.html (I'll copy it below if I have time) Open MySQL binlog Barbara Full backup and recovery in dump mode Barbara Incremental backup and recovery using binlog Barbara     JAVA implementation Realize f ...

Environment: IDEA MySQL 1. Build maven project, import coordinates: edit pom.xml, and create mybatis constraint. stay https://mybatis.org/mybatis-3/zh/getting-started.html View the latest version of mybatis and the beginning of the constraint. <!-- x.x.x by mybaits Version number --> <dependency> <groupId>org.mybatis& ...

Execution order of SQL statement: FROM <left_table> ON <join_condition> <join_type> JOIN <right_table> WHERE <where_condition> GROUP BY <group_by_list> HAVING <having_condition> SELECT DISTINCT <select_list> ORDER BY <order_by_condition> LIMIT <limit_number> 1. LIMIT stateme ...

1. Environment and conditionsMaster slave schema environment already exists host name IP address Master-slave role MHA role leo1 192.168.3.2 Master MHA-node leo2 192.168.3.3 slave MHA-node leo3 192.168.3.4 slave MHA-node,MHA-manager vip 192.168.3.6 Master-slave ensures the master-slave status is normal mysql>show slave statu ...

Original: Replication with restricted privileges https://mysqlhighavailability.com/replication-with-restricted-privileges/ By Pedro Figueiredo Guan Changlong background Before MySQL 8.0.18, the slave server performed replication transactions without checking permissions, so that the master server could get all the content. In fact, this mea ...

##Performance tuningOverview It's important to get the Zabbix system tuned for optimal performance. Hardware - use the fastest processor - SCSI or SAS is better than IDE (by using the utility hdparm you can significantly improve the performance of IDE disks) and SATA - 15K RPM better than 10K RPM, better than 7200 RPM - use fast RAID storage - ...