MySQL discrete notes-foreign key Mysql foreign key
References: about MySQL foreign keys and mysql foreign key association creation
MySQL has the same definition of "key" and "index", so foreign keys and primary keys are also an index. The difference is thatMySQL automatically indexes the primary keys of all tables, but the foreign key field must be explicitly indexed by the user. // Check the Mysql manual and find that the INDEX is automatically created from MySQL 4.1.2.
Code for creating an i
us with a class library, which provides a class of employee. It is distributed to users by header files eemployee. h and class library. Lib.Obviously, we cannot obtain the source code of the class implementation.// Emplyee. hClass employee{Public:Virtual int salary ();};Class MANAGER: Public Employee{Public:Int salary ();};Class programmer: Public Employee{Public:Int salary ();};Our company established the following classes during development:Class mycompany{Public:Void
Introduction to OCP (OCP -- open-closed principle ):
Software entities (classes, modules, functions, etc.) shocould be open for extension, but closed for modification. The software entity should be open to the extension and closed to the modification, that is, the software entity should be extended without modification (which may be achieved through the proxy mode in. net. Open for extension: when new requirements arise, you can expand the existing model to achieve the goal. Close for modificati
following payroll package already contains the Employee class, then add a Boss class to the payroll package. Boss class refers to the Employee class can not use the payroll prefix, Boss class examples are as follows (boss. java file):
Package payroll;public class Boss{public void Payemployee (Employee e){E.mailcheck (
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Save and close the file::wq!
Enable your virtual host file with a sym link to the sites-enabled directory:sudo ln-s/etc/httpd/sites-available/coolexample . com. conf/etc/httpd/sites-enabled/coolexample.com. conf
Restart Apache:sudo Service httpd Restart
Point your domain name to your serverIf your domain name isn ' t currently loading another website, you should point it to your server to test your new config.How do I depends on where your domain name is registered and wh
GoDaddy Domain name Replacement DNS
In many domain name registrars, the use of GoDaddy domain name registrars or mostly. Whether or not the majority of people today support the credit card payment, but its ordinary domain name preferential price is also relatively cheap, is within the acceptable range. We buy the domain name, need to use is the domain name resolution to the website host, many novice in the
accordance with the law to identify the site involved in yellow and illegal, to cooperate with the stop domain name resolution, while the domain name holder of all other domain names suspended resolution, timely report to the Department to deal with, and the domain name holders into the blacklist to be supervised.
5, focus on cleaning up the domain name registration and management agencies, domain name registration service agencies in the business promotion channels business partners, cooperat
Because of the well-known reasons, Aleng blog has to give up ***.cn domain name to migrate space content to godaddy,3 month 28th, I enabled the previous registration of the ***.net domain name, the data migration to the list of GoDaddy to join the ranks of the blog, due to a number of complex reasons, I only do the home page of the 301 redirect, redirect to ***.net, now has 10 days elapsed, I put this 10 da
Which editor is better for php files? what is php files? php is short for HypertextPreprocessor, an embedded html language that is executed on the server... which editor is better for PHP files?
What is php?
Php is short for Hypertext Preprocessor, an embedded html language. it is a scripting language that is executed on the server to control html, its programming usage is similar to that of C language machines. currently and in the future are the most popular website programming languages.
.aspmx.l.google.com.@ 3600 in mx 30 aspmx2.googlemail.com.@ 3600 in mx 30 aspmx3.googlemail.com.@ 3600 in mx 30 aspmx4.googlemail.com.@ 3600 in mx 30 aspmx5.googlemail.com.;@ 3600 in txt "v = spf1 a include: aspmx.googlemail.com-all"After editing, run:
# Named-checkzone tommyang.org db.tommyang.org to check for syntax errors. Then restart BIND:
#/Etc/init. d/named restart if there is no problem, the server should be able to provide the query service normally now. Runable:
# Dig @ localhost tommy
I forgot why I switched the space on Godaddy from IIS6 to iis7, but I didn't feel any improvement at the time. Recently I found that iis7 supports php5.x, most of the excellent CMS systems are built with PHP, so the idea of replacing the current website with CMS emerged.
CMS is short for content management system.ArticleImages, sounds, and videos can all be content. Naturally, any system that can manage these things can be called a content managemen
Today is going to buy a domain name, but accidentally purchased a year of domain name trading member Services.
Originally I have a discount code in GoDaddy, You can use a 6.95 dollar price to buy a domain name (the normal price is 8.95 dollars), but today I am going to buy a new domain name, found that the discount code expired, is disappointed, but accidentally found that there is another one of GoDaddy n
How to use Excel to make payroll, maybe some netizens have been using for a long time, but how to make a beautiful pay bar faster and better, see the author's method.
"Little problems to the old financial", perhaps you have been working in the financial mouth for many years, maybe you have to face Excel every day, maybe you have been accustomed to using the salary list to do employee payroll statistics and
grouping by department, there are 3 numbers in the technical part group, there are 2 numbers in the Sales section group, which do you let the database show?If you assume that you use the aggregate function after count (number), for each department group, there is only one value-the number of people under that department: Under the actual situation below, we hope to find out the name, department, and salary of each department, the highest wage of the person. Shit, a frustrated. The first comba
generally used to add similar inspection steps in multiple places. Once the consistency check process has been adjusted, it will inevitably result in multiple local modifications, not only increasing the workload, but also not guaranteeing the correctness of each inspection step. The application of triggers should be placed on the key, multi-initiator, high-frequency access data tables, excessive use of triggers, will increase the database burden, reduce database performance. Discarding the use
the outsourcing, the storage of the libraryItem scheduling, inventory counting, real-time inventory(4), production management product BOM, the main production plan, MRP material requirements, production process list, production picking, workshop control, production return, production storage(5), production management finished product inspection, inspection report, quality analysis, passing rate statistics(6), receivable management receivable documents, collection and settlement, collection and
select the Custom option to open the Customize dialog box. In the Commands tab, select the New menu item under Categories, and then drag new menu under Commands to the menu bar.
Press the Change Selection button to enter a name (such as "common documents") in the Name box of the pop-up menu.
2. Select one of the following categories (such as the Insert option) on the right, under command, select an item (such as the hyperlink option), drag it to a new menu (a common document), and name it (su
the Custom option to open the Customize dialog box. In the Commands tab, select the New menu item under Categories, and then drag new menu under Commands to the menu bar.
Press the Change Selection button to enter a name (such as "common documents") in the Name box of the pop-up menu.
2. Select one of the following categories (such as the Insert option) on the right, under command, select an item (such as the hyperlink option), drag it to a new menu (a common document), and name it (such as "
), drag it to a new menu (a common document), and name it (such as "payroll", etc.), and create the first workbook document list name.
Repeat the above action, add more than a few document list names.
3. Select a menu item in the Common document menu (such as "payroll", etc.), right-click the mouse, and, on the pop-up shortcut menu, select the Assign hyperlink → open option to open the Assign Hyperlink di
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