Python 3.7 learning notes 27 context manager
Input and output of files, connection and disconnection of database are common resource management operations. Because of limited resources. In such a scenario. If these resources are used but not released. It will cause resource leakage. Light makes the ...
Posted by mcmuney on Mon, 15 Jun 2020 19:33:05 -0700
Database integrity: prevent non semantic and incorrect data from entering the database;
Database security: prevent illegal users from intruding into the database and illegally accessing the database data.
5.1 entity integrity PRIMARY KEY
Entity integrity definition: single attribute - column level, tabl ...
Posted by pillarofautumn on Mon, 15 Jun 2020 01:01:57 -0700
The label used to loop the container forEach, see the example
The properties of foreach element mainly include item, index, collection, open, separator, close.
item: the alias of the element iteration in the collection,
Index: the index when the elements in the collection iterate
open: in the ...
Posted by mebar3 on Mon, 15 Jun 2020 00:25:08 -0700
Privilege management is a necessary module in almost every system. If the project development needs to realize the right management every time, it will undoubtedly waste the development time and increase the development cost. As a result, the caspin library appears. Caspin is a powerful and efficient access control library. I ...
Posted by topsub on Sun, 14 Jun 2020 18:44:09 -0700
Oracle trail learning experience
Annotate a custom column name
Incoming parameters: field name and annotation
create or replace procedure csp_col_comment (
p_column_name varchar, --Field name
p_Title varchar, --field comment
p_RetVal Out integ ...
Posted by techjosh on Sat, 13 Jun 2020 23:52:50 -0700
In daily work, we often need to develop reports or count the percentage and total of some data. At this time, the following functions can solve the problem quickly. They have fewer sql statements and better performance. The figure below shows the results of our statistics.
Posted by NEWDAY on Sat, 13 Jun 2020 23:15:50 -0700
Article content picture upload failed, welcome to read, eBook in white.
Statement: Refer to the source Internet, any disputes can be left a message.Standing on the shoulders of the forefathers, we can see farther.This tutorial is all hands-on, dedicated to the most practical tutorials, does not require any rewards, and only wishe ...
Posted by bambambanana on Sat, 13 Jun 2020 10:41:23 -0700
In the previous several articles, we introduced abp vNext microservice framework, development environment construction and access to the front-end framework of vue element admin respectively. After the basic functions of user role management are implemented in vue element admin, we can start business development. This article will introduce how ...
Posted by lou28 on Fri, 12 Jun 2020 03:15:14 -0700
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<!-- https://mvnre ...
Posted by coco777 on Thu, 11 Jun 2020 20:04:13 -0700
Table Join Query
1. What is a multi-table query
# Create Department Table
create table dept(
id int primary key auto_increment,
insert into dept (name) values ('Development Department'),('Marketing Department'),('Finance Department');
# Create employee table
create table emp (
id int primary key auto_in ...
Posted by 8ta8ta on Thu, 11 Jun 2020 18:00:37 -0700