common knowledge book

Summary of common knowledge points of cakephp and cakephp This example summarizes common knowledge points of cakephp. We will share this with you for your reference. The details are as follows: 1. Call templates of other controllers to redirect Method 1: Call the hello. ctp Template under/views/tasks $this -> viewPath

The following articles mainly introduce 25 basic common knowledge about Oracle databases, which plays an important role in practical application, the following articles describe the 25 basic common knowledge of Oracle databases. I hope you will gain some benefits. 1. a tablespace can belong to only one database. 2.

, the type conversion does not occur in the index column, so the index is still valid. However, if it is written in this way, the index will become invalid. Select * from EMP where to_number (EMP_TYPE) = 123 The index fails because the index column type has changed. 4) note that not all index columns are valid in the Where clause. For example: A) The where clause uses "! = "The index is invalid, B) In addition, the "|" character concatenation may also cause index failure. C) the same index Colum

Python full-stack Development 7. Module and several common modules and format knowledge supplement, pythonformatI. Module Classification One of the reasons for the popularity of Python is that it has a large number of third-party modules, so we don't have to re-create the wheel from scratch when writing code. Many of the functions to use have been written and encapsulated into libraries, we only need to cal

few records for 1 tables, the data below millions does not need to be indexed2 frequently deleted and changed tables do not need to create an index3 The data is duplicated and the distributed average field does not need to create an index, such as True,false.4 frequently-updated fields are not suitable for creating indexes5 fields not available in the Where condition do not need to create an index Some summary of the indexMysql Index Optimization AnalysisIv. three types of values that shou

or quite a lot of, see the code//Find Deep nesting//Initializing DataCompany Chinamobile=NewCompany ("China Mobile", userlist); Company Chinaunicom=NewCompany ("China Unicom", userlist); ListNewList() {chinamobile, chinaunicom}; //identify all female members of 2 companies varSelectList = Companylist. SelectMany (A = a.users). Where (b = B.sex = ="female"); foreach(varIteminchselectlist) {Console.WriteLine (item. Name+":"+item. SEX); }Here you can see that the given data sourc

,short,char)-int-long-float-double;Low to advanced can be automatically converted, advanced to low level, and between peers need to be cast.1. The default 1.0 represents a double type, and if you need to represent float, write it as 1.0f.2. When char x= ' x '; int i = 10; The formula is false? The value of the I:X output is 120, because both are variables, which upgrade the lower level to the advanced representation; false?10:x, the output of x is still x because the Java programming specificati

we can change it: Select * from users where adddate 8. Do NOT use the not in and Not in and Articles you may be interested in Note the following when querying strings with single quotes and inserting strings with single quotes in Mysql: MySQL index Operation Command (create index, re-index, query index, delete index) Summary How to locate, eliminate and avoid MySQL database performance problems Rational use of MySQL database indexes to make the database run efficiently How to solve conf

This article mainly introduces a summary of common Python knowledge points, including Set sets, functions, deep copy, and shallow copy. For more information, see 1. Set Basic Data Type A. set is an unordered and non-repeating element set. Class set (object): "set ()-> new empty set object set (iterable)-> new set object Build an unordered collection of unique elements. "def add (self, * args, ** kwargs):

the process data in the lookup table is a change, there is a delete or insert operationBinary sort tree: The structure of a tree is usually not generated at once, but in the process of finding it, inserting it when there is no keyword equal to the given node in the tree. The characteristic is that the root node is larger than the left child, smaller than the right child. You can modify the pointer based on the node location when you delete the data. Find with Binary. The number of lookups for a

directives is displayed in IE7 standards mode.Reference:Http://www.cnblogs.com/liuzhendong/archive/2012/03/21/2410107.htmlWebBrowser control in the Mask Popup script error dialog boxHttp://www.cnblogs.com/qqflying/archive/2012/07/25/2607881.htmlExperience Summary: WebBrowser Auto-click Popup Alert, Pop-up dialog confirm, mask popup, mask pop-up script error resolutionHttp://www.cnblogs.com/qqflying/archive/2012/07/25/2608038.htmlUsing WebBrowser to get content from a page iframe[Go] How to reso

Statement one: If Judgment statementSub Judgment 1 () ' Single condition judgment If Range ("A1"). Value > 0 Then range ("B1") = "positive" Else Range ("B1") = "negative or 0" End IfEnd SubSub Judge 2 () ' Multi-condition-judged If range ( "A1"). Value > 0 Then range ("B1") = "positive" ElseIf Range ("a1") = 0 Then Range ("B1") = "equals 0" ElseIf Range ("B1") 　　Statement two: IIf function judgmentSub Judgment 4 () Range ("a3") = IIf (Range ("A1") 　　Statement three: Selec

[Java Basics] common knowledge accumulation (1), java basics Accumulation 1. Difference Between = and equals: difference between null and "" 2. 15 top-level Java multi-thread Interview Questions and answers (1) Use of join in a thread In many cases, the main thread generates and starts a subthread. If a large number of time-consuming operations are required in the subthread, the main thread usually ends bef

/tftpd.template #tftp服务的配置模板/etc/cobbler/rsync.template #rsync服务的配置模板/etc/cobbler/iso #iso模板配置文件/etc/cobbler/pxe #pxe模板文件/etc/cobbler/power #电源的配置文件/etc/cobbler/users.conf #Web服务授权配置文件/etc/cobbler/users.digest #用于web访问的用户名密码配置文件/etc/cobbler/dnsmasq.template #DNS服务的配置模板/etc/cobbler/modules.conf #Cobbler模块配置文件2. Cobbler Data Catalog:/var/lib/cobbler/var/lib/cobbler/config #配置文件/var/lib/cobbler/triggers #Cobbler命令/var/lib/cobbler/kickstarts #默认存放kickstart文件/var/lib/cobbler/loaders #存放的各种引导程序3. Syst

Experts naturally make a fortune, while common sense is summed up by P people for years to survive, survive, and survive. When experts differ from common sense, should I trust experts or knowledge? Before entering the winter, experts began to talk about the cold winter of the millennium, and I thought, "Is it true ?", Because there is an old saying "warm in wi

parameter sequence represents an ordered type. Here's a note: sequence is not a specific type in Python, but a series of types. list, tuple, string all belong to sequence.ImportRandomPrint(Random.choice ("Learn python"))Print(Random.choice (["Jgood"," is","a","Handsome"," Boy"]))Print(Random.choice ("Tuple","List","Dict")))#XI#Jgood#Dict5:random.randrangeRandom.randrange ([start], stop[, step]), from within the specified range, gets a random number in the collection incremented by the specified

terminal. 37, ctrl+alt+l– lock screen.2. Export OrderSets or displays environment variables.Reference: Http://blog.sina.com.cn/s/blog_7ead698501015zz2.html. This tutorial contains the meanings, parameters, and routines of export.3. grep commandThe grep command in a Linux system is a powerful text search tool that uses regular expressions to search for text and print matching lines. grep full name is global Regular ExprEssion Print, which represents the global regular expression version, whose u

)); System.out.println (s); }}The date of the above System.out.println (new date ()) output is not a habit, and the following will make you more vulnerable:DateFormatimport Java.text.dateformat;import java.util.Date; public class Formatdemo {public static void main (string[] args) {//TODO auto-generated method Stub Date d = new date (); DateFormat f = dateformat.getdateinstance (); //get the default date formatting instance DateFormat ff = dateformat.getdatetimeinstance ();

"One Minute Knowledge" common Collection list, Map, set The difference between collection and collections Collection is an interface, it is the parent interface of set, list and other containers; Collections is a tool class that provides a series of static methods to assist with container operations, including searching for containers, sorting, threading security, and so on List, Map, Set List You can all

, DESC reverse)SELECT * from Bms_project order by Project_budget DESC;8.group by: ... Group. Typically used with aggregate functions (count (), SUM (), AVG ())Select Project_type,sum (project_budget) from Bms_project Group by Project_type;Note: The fields following group by are consistent with the fields of the non-aggregate function after select.9.limit x, y (x: Start position, Y: Offset value)Select Project_budget from Bms_project ORDER BY project_budget desc limit 0,5;Remove the first five ba