1. The power supply socket of the oscilloscope must be a tripod socket, and it must be grounded reliably. In the absence of grounding wire, the power supply plug of the oscilloscope should pay attention to dividing the zero line and the fire line when it is connected, and the probe grounding wire of the oscilloscope should not be charged at one end.
Two, when testing the signal on the line, it is necessary to connect the ground wire probe before measuring the information. Because without first addressing, the probe may be electrified and damage the test element.
https://github.com/Sage-Bionetworks/BridgeResearcherUI.git
Introduction to database
1concept
3 relational database in Song Dynasty (pure theory)
Relational database is the use of Microsoft Corp)
noSQL
MangoDB,Redis
5sqlbrief introduction
Structure Query Language >:
client partmysql.exe” document, the operating environment iscmd > port number-u localhost” means the machine. 127.0.0.1” means the machine. If it is the machine, it can be omitted.
-P default, it can be omitted.
-u >root
DB DataBase ( corresponds to the form in reality.)
Record
>.
> Library option.
explains:
> is used to set the stored character...
recursive directory generator mode, else in the TMPShow that getting yield is indispensable, and if you want to use a generator in a recursive algorithm, you need to explicitly get all yield values in the generator’s original function (first call)
def get_file_recur(path):
children = os.listdir(path)
for child in children:
qualified_child = os.path.join(path,child)
if os.path.isfile(qualified_child):
yield qualified_child
else:
tmp = get_file_recur(qualified_child)
for item in tmp:
yield item
for file ...
HibernateIt is a high-performance object relational persistent storage and query service.
1. What is Hibernate?
1、Hibernateconcept
HibernateIt is the framework of data access layer and encapsulates JDBC. It is an object-oriented solution for data access.
2、HibernateRole
Hibernate can directly access objects, and Hibernate automatically converts this access to SQL execution, thus achieving the purpose of indirect access to the database and simplifying the data access layer code.
Two, why use Hibernate?
1、HibernateComparison with JDBC
1）The use of JDBC has the following disadvantages:
-...
Reading catalogues
1. What is XML? What are the characteristics?
2. Get tag properties
3. Get child Tags
4. Get label attribute values
5. Get data between labels pairs
6. Example
7. summary
Back to the top
1. What is XML? What are the characteristics?
xmlThat is,Extensible markup language，It can be used to mark up data and define data types. It is a source language that allows users to define their own markup language.
Example: del.xml
Structurally, it is much like the HTML hypertext markup language. But they are designed for different purposes. Hypertext markup languages are des...
Super good blog, summary is very comprehensive:
https://www.cnblogs.com/yangecnu/p/Introduce-Red-Black-Tree.html
The core idea of object-oriented programming is data abstraction, inheritance and dynamic binding。By data abstraction, the interface between classes can be separated from implementation.Using inheritance makes it easier to define new classes that are similar but not identical to other classes.Using dynamic binding, you can ignore the differences between similar classes to a certain extent and use their objects in a unified way.
The function of virtual function is to realize polymorphism. Polymorphism is to separate the interface from the implementation, using a common approach, but using di...
