cdb meaning

String formatting symbolic meaning Symbol Description %c Formatting characters and their ASCII code %s formatting strings %d formatting integers %o Formatting an unsigned octal number %x formatting unsigned hexadecimal numbers %x Format unsigned hexadecimal number (uppercase) %f Format fixed-point numb

A lot of friends in the tuning with MySQL will certainly use the explain to see the execution of the SELECT statement, here is a brief introduction to the results of the meaning of the two columns.1 Type column The official saying that this column represents the "type of access", and more commonly, the way MySQL finds the data rows needed. One is to introduce the worst from the most efficient to the best: all this is called a full-table scan, and no i

A lot of friends in the tuning with MySQL will certainly use the explain to see the execution of the SELECT statement, here is a brief introduction to the results of the meaning of the two columns.1 Type column The official saying that this column represents the "type of access", and more commonly, the way MySQL finds the data rows needed. One is to introduce the worst from the most efficient to the best: all this is called a full-table scan, and no i

Meaning of DBUnitdb, or decibel, is a very common unit in the field of electronics. This unit is characterized by the use of logarithms to represent the original data. 1 shell = 10 db = 10dB = 10 times times PowerFor an amplifier,power Magnification Ap = ten lg (PO/PI)voltage Magnification Au = LG (UO/UI)current Magnification Ai = LG (IO/II)For example: amplifier magnification of 40dB, indicating that its voltage amplification is 100 times times, curr

[Go] Return html tags for their original meaning, and html tags for their meaning To tell the truth, the word "div + css" does not know how many people are harmed. Maybe the author's intention is correct, but the followers have misinterpreted its meaning in terms of performance, the whole page should be a combination of div + css files. In this way, there is no v

The recent use of curl feeling is still very convenient, looked at the cookie file format of curl generated, some of the value of the meaning is not very clear, to find some information about the cookie looked down, do a memo The cookie file format generated by PHP Curl is as follows #Netscape HTTP Cookie File#http://curl.haxx.se/rfc/cookie_spec.html#This file is generated by libcurl! Edit at your own risk.Jifen. xx.comFALSE/FALSE0PHPSESSID Dmdvk314ru

Option meaning of info. plist, meaning of info. plist 1. application does not run in background (container name: UIApplicationExistsOnSuspend) from the end of iOS4.0, when you apply the program line, press Home terminal, the application does not parse the current line, but hides in the background. Therefore, if you want to download the current program line after you press Home then, check this option. 2. A

This may be used in the shell, including DOS.Null is something called a null bucket, and the benefit of redirecting the output to it is that the file size is not constantly increasing due to too much content in the output. In fact, you think that null is nothing, that is, the output of the command is discarded.1 indicates standard output, 2 indicates standard error output, 2>1 indicates the standard error output is redirected to standard output, so that the normal output and error output of the

The meaning of the forest root domain in the domain tree, and the meaning of the domain forest root domain Contoso has many IT resources in the company's IT environment, and these IT resources are all in a state of decentralized management, which virtually increases the management cost of contoso, moreover, the management system cannot be implemented in the actual production environment. So how can we solv

Chapter eighth Introduction to object-oriented programmingThe contents of this chapter:What is object-oriented programmingOOP technologyThe Windows forms application's dependency on OOP8.1 Meaning of object-oriented programmingThe programming method described earlier, called function (or procedural) programming, often leads to so-called single applications, where all functions are contained in several code modules (often a code module). with OOP, many

Android Log Tag meaning, androidlogtag meaning One of the most important methods to analyze Android problems is to analyze logs in events. there are many system logs in the log, some of which are not very familiar with the meaning. The following is the system log tag obtained from the android source code. The Tag description is as follows: "30005 am_create_activi

Where T: class meaning, whereclass meaning public class DbEntityEntry This is a parameter type constraint. The specified T must be of the Class type. . NET supports the following types of parameter constraints:Where T: struct | T must be a structure typeWhere T: class | T must be of the Class typeWhere T: new () | T must have a non-argument ConstructorWhere T: NameOfBaseClass | T must inherit the class nam

Linux basic [Folder meaning], linux basic meaning The linux File directory is a tree directory. Bin --> Executable File Boot --> operating system boot file, system kernel, boot Information Dev --> device, device information, computer hardware device information Etc --> System Configuration directory Home --> home Directory, user folder Root --> super administrator folder with the highest Permissions

On the physical meaning of negative frequency in spectrum --Reading analysis * Statement: This article is a large number of references to Chen Hui deep, Fang Haiyan of the relevant paper content* This article is the best I've ever read to explain the negative frequency of the spectrum, just to pay tribute to the two authors in this blog post. Absrtact: This paper discusses the physical

Recently came out a six popular language, one of which is "noisy too set." Chinese transliteration from the English "not at all". Singer Huangxiaoming, who sang "One World a Dream", was teased by netizens for not being in all, which became a popular language on the Internet. The word is less popular than the other 5, so it is suspected of being a so-called "internet buzzword" deliberately packaged to hype stars. not on all No, not at all. Not in all is a very common expression in spoken lan

| +------------+ | 0000000010 | +------------+ mysql> ALTER TABLE t change column ID ID int (3) Zerofill; Mysql> select * from T; +------+ | id | +------+ | 010 | +------+ mysql> mysql> ALTER TABLE t change column ID ID int (4) Zerofill; Mysql> select * from T; +------+ | id | +------+ | 0010 | +------+ mysql> mysql> insert INTO T (ID) values (1000000); Mysql> select * from T; +---------+ | ID | +---------+ | 0010 | | 1000000 | +---------+ As you can see from the test above, "(M)" Speci

Baidu Crawler in the crawl and processing, is based on the HTTP protocol specification to set the corresponding logic, so please webmaster also try to reference the HTTP protocol on the meaning of the return code to set the definition. 　Baidu Spider to the commonly used HTTP return code processing logic is this: 1, 404 404 Return Code meaning is "not FOUND", Baidu will think that the Web page has been in

Python: The Meaning of self and __init__ + why have self and __init__ backgroundsReply:I wrote some python tutorials that need to be able to seeQuestions from Songshoujiong:What is the meaning of self,__init__ in python?Why do you have to have self,__init these things?Before you explain, let's say a few words.1. So far, although I have written not very little Python code, but there is really not too much co

The meaning of shell variable $#,[email protected],$0,$1,$2 in Linux is explained:Variable Description:$$The PID of the shell itself (ProcessID)$!PID of the Shell's last running background process$?End code of the last Run command (return value)$-Flag at a glance using the SET command$*All parameter lists. such as "$*" in the Case of "" ", in the form of" $ $ ... $n "output all parameters.[Email protected]All parameter lists. such as "[email protected

As a bridge between Java and database, JDBC is one of the foundation of Javaweb background, which needs us to be familiar with its principle and usage. JDBC General steps for using are: 1, the use of reflection loading driver, such as Class.forName ("Com.mysql.jdbc.Driver"); 2, access to the database connection objects, such as Java.sql.Connection conn = Drivermanager.getconnection (Url,user,password); 3, create statement objects or PreparedStatement objects, such as PreparedStatement ptmt=conn.