Definition Of Primary Key And Foreign Key In Database

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Delve into the primary key issues of SQL Server tables

The logical design of database is a very broad problem. In this paper, the main key design of the table is discussed in the design of MS SQL Server, and the corresponding solutions are given. Primary key design status and problems about database table primary key design, in general, based on business requirements, based on business logic, the formation of primary key. For example, when sales to record sales, generally need two tables, one is the summary description of the sales list, records such as sales number, the total amount of a class of cases, and the other table record of each commodity ...

How to define foreign key in MySQL

If a computer manufacturer, its database holds machine and accessories product information. The table used to save the whole product information is called pc; the table used to save the parts supply information is called parts. There is a field in the pc table, used to describe the type of CPU used in this computer; there is a field in the parts table, the description of the CPU model, we can think of it as a list of all CPU models. Obviously, the CPU used by this manufacturer must be a model that exists in the supply information sheet. At this time, two tables ...

Basic knowledge and working principle of search engine

Absrtact: Hello, I am specialized in SEO, for several months have been in the maintenance and optimization of the massage list www.yziyuan.com this site, and summed up a lot of experience and knowledge. Today to share is the "search engine basics and work principle", which is good, I am specialized in SEO, for several months has been in the maintenance and optimization of the massage list www.yziyuan.com this site, and summed up a lot of experience and knowledge. Today to share is "search engine basics and work principle", this is the most basic ...

Second Lesson notes: Search engine basics and working principles

The intermediary transaction SEO diagnoses Taobao guest Cloud host technology Hall Everybody Good, I am specialized in the SEO, for several months has been in the maintenance and the Optimization massager list www.yziyuan.com This website, and has summed up a lot of experience and knowledge from it.   Today to share is "search engine basics and work principle", this is the most basic concept, the first part: What is a search engine?   1, definition? Official definition: Search engine refers to a certain strategy, the use of special ...

Toward Marketing 2.0 times--Panorama article

Go to Marketing 2.0 Times Editor's note: This is a "sales and market" to write a big article, should have more than 12,000 words. Although writing has been written more comprehensive, but still deeply inadequate, especially in how to find the crowd, how to carry out marketing plans, how to make full use of the wisdom of the masses, and so on, not how to write, please wait for my later articles.   I am not a person who likes too much theory, just marketing 2.0 can't do some work. Marketing 2.0 is not a ready-made tool to provide existing market competition, but a bar to the future market competition ...

Architecture analysis of video chat system and video chat program

The intermediary transaction SEO diagnoses Taobao guest Cloud host technology Hall the article purely from the technical angle to tell how can construct a video chat website stationmaster needs the high quality video chat system, is my long-term experience in the video industry, please do not use the architecture described in this article for operating violations of national law video chat site. A good video chat system's primary goal is to meet the video chat webmaster operational needs. And for the video chat webmaster, the main requirements include three aspects: 1, Security 2, Performance 3, function. This article will be from this ...

Medical website Construction Plan

The intermediary transaction SEO diagnoses Taobao guest cloud host technology Hall Medicine website Construction Plan Directory One, project Goal 3 1.1 demand Analysis 3 1.2 website target and expectation 3 1.3 website design principle 4 1.4 Solution 42, website overall structure 6 Third, the main columns and website management function Description 7 3.1 Home 7 3.2 Medicine 7 3.3 News Center 7 3.4 Product Show 11 3.5 ...

Mastering the "core" of large data to achieve precision marketing

As a business person, you may have to travel by air frequently. If one day, when you sit on the plane, in the absence of any prior request, a smiling stewardess will be a cup of fresh green tea in front of you, you must not be surprised. Because by sorting and analyzing your previous flight information, the airline will be able to understand the various preferences of your flight and provide you with attentive service. This is not a myth. According to the reporter understand, some domestic airlines are doing this research, hope that through the detailed analysis of passenger data to achieve ...

Big Data 9 Lessons

Innovative report from the dean of top research institutes when all our actions and our lives can be "data", the company that holds the data is like owning a rich gold mountain.   As Victor Maire-Schoenberg says, the big data age is "the future that has happened," and in this already-occurring future, there is no bystander. December 19, 2013, by the boutique media "digital Business Times" sponsored by the "Great data creation of the era of Subversion" 2013 China Summit Forum in Beijing to make a grand Holiday Crowne Plaza Hotel ...

50 Most personalized websites, how much do you know?

According to foreign media reports, the United States "Time" magazine every year will be the most personalized list of websites. These sites on the list are both interesting and informative, and can help you save time and money and may even change your life. As in previous rankings, most of the 50 most personalized web sites on the magazine's list are still obscure.   The editors of Time magazine have found that these sites are not only interesting, creative and appealing, but also helpful to you. 1. LastPass website security experts say your ...

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