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one, key and primary key differenceCREATE TABLE Wh_logrecord (logrecord_id Int (one) not NULL auto_increment,User_name varchar (+) default NULL,Operation_time datetime default NULL,Logrecord_operation varchar (+) default NULL,PRIMARY KEY

SQL CHECK constraintsCHECK constraints are used to limit the range of values in a columnIf a CHECK constraint is defined on a single column, the column only allows a specific valueIf a CHECK constraint is defined on a table, the secondary constraint

Let's take a look at the third topic of WCF to verify the identity of a user, and the third topic of wcf. Today, I mainly write a message about the use of header messages to verify user information. I will draw a picture below to see the picture

1. Macro definition function:Example: #define DO{EXP} while (0) and # define EXP What is the difference, where is the benefit?Define complex code to prevent errors such as semicolons, or mismatched parentheses. Like what:Defined:#define SWITCH (x, y)

C language keywords (2)10. goto keywords In general, the encoding level is inversely proportional to the number of times used by the goto statement. In my opinion, disable the goto statement. 11. void keyword 1. void modifier function return

XML & DTD & XML Schema LearningXML (eXtensible Markup Language) eXtensible Markup Language. Xml is particularly important in web service programming. It can be used as a carrier for data transmission during network transmission. Xml, as a metadata

Linux/Unix shell scripts Execute SQL statements across servers and instances during database O & M, it is inevitable that you need to query databases across multiple servers and multiple Oracle instances. For example, you need to check the value of

First to fourth useUse one:Defines an alias for a type, not just a simple macro substitution. Can be used as multiple objects that declare a pointer type at the same time. Like what:char* PA, PB; The majority does not conform to our intent, it only

First to fourth useUse one:Defines an alias for a type, not just a simple macro substitution. Can be used as multiple objects that declare a pointer type at the same time. Like what:char* PA, PB; The majority does not conform to our intent, it only

Guide The Go language, also known as Golang, is an open-source programming language originally developed by Google, which is designed to follow the 3 principles of simplicity, security, and speed. The go language has a variety of debugging,

Understanding requireJS-Implementing a simple module LoaderIn the previous article, we have emphasized more than once the importance of Modular programming and the problems that can be solved: ① solve the single file variable naming conflict problem

Http://www.cnblogs.com/charley_yang/archive/2010/12/15/1907384.htmlFirst to fourth useUse one:Defines an alias for a type, not just a simple macro substitution. Can be used as multiple objects that declare a pointer type at the same time. Like

These days to write a few small program practiced hand, when preparing to export a class, I found that I do not know if the extension DLL without MFC, how to export. But I know dllexport can export functions and variables, and MFC extension DLL even

  I learned from C # advanced programming that there are two ways to pass parameters to a Thread. One is to use the Thread constructor with ParameterizedThreadStart to delegate parameters, another way is to create a custom class and define the

20145216 "Java Program Design" 6th Week study summary textbook Study content summary tenth chapter input/output 10.1 InputStream and OutputStream If you want to take the data out of the source, you can use the input stream, and if you write the

MySQL uses UNIQUE for non-repeated data insertion. mysqlunique SQL UNIQUE constraints The UNIQUE constraint uniquely identifies each record in the database table.UNIQUE and primary key constraints provide uniqueness guarantee for columns or column

This article describes how to use filters in the PHP Yii Framework. Some Common Core filters are listed in this article. For more information, see Yii filter introduction A filter is a piece of code that can be configured to be executed before or

Many PHP fans feel that they are difficult to understand and master the concept of classes in PHP during their learning process. although they know that classes already exist, however, since there are few opportunities for access and use at ordinary

The hair production method in this tutorial is relatively fast. General idea: use a pencil tool to make some small points and define it as a paint brush. Then the hair path should be hooked up. the path should be a little thinner, and then the path

This is a creation in Article, where the information may have evolved or changed. Guide The Go language, also known as Golang, is an open-source programming language originally developed by Google, which is designed to follow the 3