Programmer Think

1. Suggest users and groups su root　　#Switch to root groupadd oinstall　　#Create user group oinstall groupadd dba　　#Create user group dba useradd -g oinstall -g dba -m oracle　　#Create oracle users and join oinstall and dba user groups passwd oracle　　#Set the login password of the user oracle, do not set the password, unable to login i ...

In flask, many people prefer to operate the database through SQLAlchemy. In this case, it is recommended to use package instead of module to split the data model into a separate module. Such an approach is not necessary, but more reasonable. Flask-SQLAlchemy Extension Because SQLAlchemy is a general database abstracti ...

Recently, someone asked this question in the interview. Before that, they had not studied the specific use logic of the joint index, consulted several articles, and came to some conclusions after testing Test environment: SQL Server 2008 R2 The test results are similar to the query mechanism of MySql joint index. We can think that MySql is the ...

Getting to know JDBC 1, JDBC concept jdbc English full name: java database connectivity is a set of specifications for Java to access database, which can be understood as a set of classes and interfaces provided by java to connect database The relationship between jdbc and database driver: 　　 2, jdbc easy to use Usage process: (the driver jar ...

1, Implementation method 1. Pure template language implementation 2. Implementation of custom simpletag (in essence, it simplifies the judgment of pure template language) 2, Fundamentals The principle is to match the url filter conditions through django routing system, take the filter conditions as the database query results, and return the ...

There are many attributes of fields in MySQL, and the impact on performance can be large or small, so it's necessary to explore the attributes. 1, NULL / NOT NULL For external programs, NULL is an unknown, imprecise, and indescribable value. Therefore, it is clearly stipulated in the development specifications of many companies that it must be ...

According to an example of a project, this paper records and shares the process and relevant settings of python's displaying the content of database to the program interface, and explores the usage of python's operating database. Main contents to be shared: 1. Displays the database contents. 2. Modify database content. 3. The table control spec ...

PostgreSQL can report the progress of some commands during command execution. Currently, the commands that support progress reporting are CREATE INDEX, VACUUM and CLUSTER. This range may be expanded in the future. CREATE INDEX Whenever an index is created or REINDEX is run, the PG > stat > progress > create > index view will contain ...

Author: Tang Youhua https://dzone.com/articles/a-birds-eye-view-on-java-concurrency-frameworks-1 1. Why to write this article When NoSQL became popular a few years ago, like other teams, our team was keen on exciting new things and planned to replace an application's database. However, when we go deep into details, we think of what a wise man ...

Next blog CentOS 7.4 installation and deployment openstack [Liberty version] (I) , this part continues to cover the following parts 1, Add block device storage service 1. Service Description: OpenStack block storage service provides block storage for instances. The allocation and consumption of storage is determined by block storage driv ...