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Table structure modification background In general, you should try to design well at the beginning, because once the database design is completed, it is better not to make major changes. However, no one can guarantee that my watch will always be sufficient and may need to be changed at any time. Therefore, we still need t ...

Java design pattern - Data Access Object Pattern The data access object pattern or DAO pattern separates the data access API from advanced business services. DAO patterns typically have the following interfaces and classes. The data provider interface defines standard operations for model objects. The data access object c ...

System Convention Download directory of installation files / opt/software Mysql directory installation location: usr/local/mysql Database save location / data/mysql Log saving location: data/logs/mysql Dependency package required for MySql installation Before installing mysql, you'd better install the dependency package ...

oracle 11g single instance silent installation AURHOR: Oracle_Ran Environmental Planning: OS Version : Red Hat Enterprise Linux Server release 6.7 (Santiago) Oracle Version: 11.2.0.4 Please refer to Oracle single instance installation document for operating system environment configuration   1. Upload the Oracle installation media, enter the ...

MySQL GROUP BY statement The GROUP BY statement groups the result set based on one or more columns. We can use COUNT, SUM, AVG, and other functions on grouped columns. GROUP BY syntax SELECT column_name, function(column_name) FROM table_name WHERE column_name operator value GROUP BY column_name; Example demonstration T ...

Due to the loss of control file caused by a power failure, the startup database reported ORA-00205 error: SQL> startup ORACLE instance started. Total System Global Area 419430400 bytes Fixed Size 2925120 bytes Variable Size 285216192 bytes Database Buffers 125829120 bytes Redo Buffers ...

Environmental preparation Front end framework semantic ui Python 3.6.4 pip install django The development tool is pyCharm Data model design The user table contains the following information User name Full name Gender Password Cell-phone number Creation time Update time Is it effective? The user/models.py user model is as follows user is the ...

Oracle - > auto send AWR Report September 21, 2016 09:31 Requirement Description: Daily or regular manual use of AWR reports to check the status of Oracle database is not only time-consuming but also labor-intensive, requiring the use of scripts to automatically collect AWR reports.    Analysis scheme: Script to collect AWR report: $o ...

Summary Today, I saw the installation image of zstack on the official website, and found that it was released on March 24, 2018. Because the local environment is a test environment, and I haven't tried to upgrade zstack, I plan to upgrade zstack Things to know before upgrading First of all, zstack supports two upgrade methods on the official w ...

Original address: http://te-amo.site/user/article/info/ARTICLE20180223085118171 Written in the front Exceptions are inevitable in project development, so it is important for an application to capture and handle exceptions uniformly in the project. It is easy for developers to find the cause of errors, and users ...