concept pm3

Notification Mechanism (concept), notification mechanism concept 1. notification center) The notification center is a singleton class created using the following code. [NSNotificationCenter defaultCenter]; 2. Notification (NSNotification) // A complete notification generally contains three attributes:-(NSString *) name; // notification name-(id) object; // notification publisher (who wants to publish the no

analysis, design, and implementation; On the contrary, the pattern embodies the whole idea of the program, so sometimes it appears in the analysis or in the schematic design phase. This is an interesting phenomenon because patterns can be implemented directly by code, so you may not want to use patterns before you design or encode them in detail (you may not actually realize that you need a particular pattern before you design and code in detail).

distribution (histogram information), Number of NULL valuesSELECT -- Number of unique values -- the minimum value on the column -- the maximum value on the column -- Select rate factor (density) -- Number of NULL values -- Number of buckets in the histogram -- Types of histograms from User_tab_columnsV. Cases Case: When you query a table, the resolution plan returns the result set rows are completely incorrect, and after a large number of DML tables are not analyzed, th

Iterator concept, generator ConceptIteratable objects: Objects that can be directly acted on by the for King are collectively referred to as iteration objects: Iterable 1 # to determine whether an object is an Iterable object, first import the Iterable module in collections 2> from collections import Iterable3> isinstance ([], Iterable) 4> True5> isinstance (100, Iterable) 6> FalesIterator Can be called by the next () function and continuou

Decorator Concept Actual use of dry goods and decoration ConceptDefinition: Essentially, it is a function (decorated with other functions) that adds additional functions to other functions. Principles: The source code of the decorated function cannot be modified. The call method of the decorated function cannot be modified. Implement the knowledge reserve of the decorator: Functions and "variables" High-order functions Nested Functions De

Android color design concept and android Design ConceptColor Colors are inspired by contemporary buildings, road signs, crosstab charts, and sports ground pavilions. This creates a bold color expression that activates the color and is in stark contrast to the monotonous surrounding environment. Emphasize bold shadows and highlights. Creates unexpected and vibrant colors. Color sample-0.13 MB (.zip) UI palette The color palette is based on some basic

QQ concept version after a year of secret research and Development, finally opened her mysterious veil, to the world to show her true face, as a brand new products, as well as the internal closed secret research and development of many factors, may be a lot of people want to understand the QQ concept version of the design process and product design concept, Here

QQ concept version after a year of secret research and Development, finally opened her mysterious veil, to the world to show her true face, as a brand new products, as well as the internal closed secret research and development of many factors, may be a lot of people want to understand the QQ concept version of the design process and product design concept, Here

Block chain High starting point, whether the Government, experts, enterprises or from the media, our description of the block chain is used the most absolute word, "block chain Up", "block chain will eventually subvert our lives", "block chain triggered the system revolution" credit. In this fast-changing market, the block chain is the concept of speculation. or have roots. Beware of the concept hype of

alternative is easy to leak, and some corrosion of the liner, so the probability of failure will be A product can not be the best indicators, Tiger Balm may not be everything. Many consumers in the purchase of refrigerators, pay special attention to the refrigeration effect of refrigerators, that the stronger the better the cooling effect. Although the freezing force is a measure of refrigeration equipment, an important technical indicators, but the use of refrigeration appliances are differen

IntroductionProcess synchronization is an operating system level concept, in the context of multi-channel programs, there are different constraints, in order to coordinate this mutual restrictive relationship, the realization of resource sharing and process collaboration, so as to avoid conflicts between processes, the introduction of process synchronization.Critical ResourcesIn the operating system, a process is the smallest unit of possession (a thr

Before I wrote an article about the revolutionary trend of APP product design in the future, I suddenly found a problem, the article itself is actually a trend to talk about, is a more need to stimulate the imagination of things, not a rough black-and-white case can come to the right and wrong. We need to think of a way to create a variety of details that might fit the scene and then find a support point. But that article took are the current some of the columns, leading to a lot of friends of t

first, geometric correction 1. Concept is the process of eliminating or correcting the geometrical errors of remote sensing images; is to realize the transformation of the coordinate system of digitized data and the correction of deformation error of drawing (yellow apricot Element). Common GIS software usually has the functions of affine transformation, similarity transformation and two-time transformation. Affine transformations can scale the coordi

Transferred from: http://blog.csdn.net/hdujinhuihui/article/details/8686817High-end memory is an important concept in Linux, a concept that was very confusing when it came to Linux. In fact, this concept is relatively simple, understanding the concept, it is necessary to trace the memory management of Linux.Previously,

Since the birth of Xiao Yue, we do not sigh: God horse Furong sister, and Chun, Fengjie and worship the moon is a cloud. Increasingly fierce competition in the browser market and the same as the new concept of "dual-core browser", since the dual-core browser, we will not be with the pace of Intel, AMD launched the three-core, quad-core or even eight-core browser, so I put forward the Multi-Core browser, Interactive rumors a soft in the hands of all ha

Although unlike Cmaptools's focus on "concept maps", Xmind is still a useful tool for quickly creating concept maps. The 5 steps to create a concept map are recommended here xmind. 1. The first step In my opinion, the first step should be to focus on drawing a sketch or listing some important ideas and concepts. This gives you the opportunity to organize your i

optimization. Of course, with the search engine algorithm slowly improved, the weight of the site is also a step-by-step in many other aspects to be reflected. such as domain name age, outside the chain quality and so on. SEO3.0, that's the user experience. In this parlance, when the SEO into 3.0 times, SEO is not search Engine optimization (search engine optimization), but Searcher experience optimization (search experience Optimization). SEO3.0 is the "pseudo

Label:Introduction to cluster concept (i) Overview: write down the original intent and motivation of this document, derived from the Oracle Basic operating Manual of the previous article. The Oracle Basic Operations Manual is a summary of the author's vacation on Oracle's foundational knowledge learning. Then form a summary of the system, a review review, the other is easy to use. This document is also derived from this text. Before reading t

Open the Magic Box of wisdom-Mind Map and concept map application This is a book that everyone needs. It is a novel book with unique style. It takes only two hours to read this book, or even one hour to activate your unlimited creativity, this will lead to a leap in your thinking quality and work ability. Basic Information Author:Luo Hui[Introduction to translators] Press: Tsinghua University Press ISBN:9787302255857 Mounting time: Published on: Febru

From Wikipedia, the free encyclopedia Jump: Navigation, search Two offshore skimmers tow an Oil Containment Boom loss ss the water during an oil spill and recovery proof of concept demonstration. an Oil Containment Boom is a floating barrier, which is used to respond quickly and collect and recover offshore oil spills.The proof of concept demonstration focused on the abilityU. S. Navy and host nation ass