In the work, a series of data are often added automatically, and a scenario is envisaged.A total of 10 coupons will be issued (the following operations are in time series)1) user 1 requests to receive 1 coupon;2) process 1 queries the remaining 10 coupons in the database, and the code updates the number of coupons. At this time, the number of ...
Posted on Mon, 11 Nov 2019 14:58:14 -0500 by sholtzrevtek
Paging queries can be found everywhere on the web, so what's the principle?The following is a brief introduction to the implementation of limit based on MySql database.
First, make sure why you want to use paging queries, because the data is so large that queries cannot be displayed on all pages. If they are displayed on all pages, it will also ...
Posted on Mon, 11 Nov 2019 12:39:38 -0500 by deathrider
Note: update with the previous blog
Because the whole open source openstack installation process is too tedious, the command is too long, too tedious, so the entire installation command is written as a shell script.
Too many scripts have been pushed github Source hosting center.
This is the content of this script github Warehous ...
Posted on Mon, 11 Nov 2019 11:38:11 -0500 by JC99
Selenium Is a tool for Web application testing. Selenium tests run directly in the browser, just as real users do. This feature provides a choice and direction for the development of crawlers. Because it depends on the browser itself, the premise of using the selenium Library of Python is that you need to download the corresponding ...
Posted on Mon, 11 Nov 2019 10:23:15 -0500 by mrjiggyhill
The new LOGTIME command-line parameter available in Oracle Data Pump Export and Import allows you to request that messages displayed during export and import operations be timestamped. The valid values are:
NONE - no timestamps on status or log file messages (same as the default)
STATUS - timestamps on status mes ...
Posted on Mon, 11 Nov 2019 09:47:18 -0500 by LuiePL
I. Python thread module
1. Thread introduction
A standard thread consists of thread ID, current instruction pointer (PC), register set and stack. Thread is an entity in the process, which is the basic unit independently scheduled and dispatched by the system. The thread itself does not have system resources, and shares all the resources of the ...
Posted on Mon, 11 Nov 2019 08:18:09 -0500 by danwatt
1. Overview of reflection
2. Class CLASS Class CLASS Class KINDS BEFORE FORMAL USE OF REFLECTION
3. Use of reflection
Many blog posts explaining reflection do not elaborate on the Class class, ~including me before of course,~. Such posts only make reflection superfici ...
Posted on Sun, 10 Nov 2019 19:42:35 -0500 by copernic67
The core of blockchain is decentralized storage. Traditional database solutions, including relational database and non relational database, belong to centralized storage. Decentralized storage means that there is no data center, and each data node contains the information of the previous data node.
An example is given to understan ...
Posted on Sun, 10 Nov 2019 16:38:52 -0500 by karan23424
Android's database is SQLite, and the sql statements used are all interoperable. Let's not talk about it here. Look at the code:
static ArrayAdapter adapter;
ArrayList<User> us ...
Posted on Sun, 10 Nov 2019 14:58:36 -0500 by pesale86
Labels (space delimited): GreenPlum
In the process of configuring GreenPlum, you need to pay attention to the following points:
Find the installation package
Installation dependency, Gun version needs attention
Detailed installation procedure reference Greenplum installation introduction
I am a computer virtual machine insta ...
Posted on Sun, 10 Nov 2019 14:42:13 -0500 by antisback