function keys

primary key is a selected candidate key. I understand what is a candidate keyTake a look at the question firstIn the SQL Server database, there is a student information table as follows. In this table, the attribute set that cannot be used as the candidate key is () (select one)Student ID name gender age Division Major20020612 Li Hui male 20 Computer Software Development20060613 Zhang mingnan 18 Computer Software Development20060614 Wang Xiaoyu female 19 physical mechanics20060615 Li Shuhua, fe

Tips for using Mac machine express keys and mac express keys 1. Hide the shortcut key for displaying the dockCmd-opt-d 2. How to quickly call up the command terminal or call up other programsBy installing Alfred, Alfred is a powerful weapon-Alfred 3. After the Dock is hidden, move the mouse over it. When the Dock is displayed, there is a slight delay.You can use the following terminal commands to make adjus

Common Vim shortcut keys and keyboard diagrams, and vim shortcut keys and keyboards Common Vim shortcut keys H-move the cursor one character left. j-move the cursor one character down. K-move the cursor up one character l-move the cursor down one character to 15 rows-15j Ctrl + f-move one page down on the screen Ctrl + d-move half page down Ctrl + B-move one pag

The most common shortcut keys of intellij idea and the shortcut keys of intellijidea Most common shortcut keys * Add a copy to favorites. 1. Ctrl + E to display the list of recently edited files2. Shift + Click can close the file3. Ctrl + [or] can jump to the beginning and end of braces4. Press Ctrl + Shift + Backspace to jump to the Last edited location.5. Pres

From: http://hongzhguan.iteye.com/blog/1479563 Solution 1: Problem: In ubuntu, the direction keys cannot be used when VI is being edited, and the return keys cannot be deleted. Solution: You can install the vim full version. In the full version, the keyboard is normal. After installation, use the VI command. Install VIM: Ubuntu is pre-installed with the vim tiny version, but requires the vim fu

Comrades who use a normal non-MAC-brought keyboard and want to use the keyboard on a Mini Mac, it is recommended to use the virtual keyboard that comes with the Mac system, so you can see what's on the Mac system for each key on the normal keyboard.Here's how to view the virtual keyboard on your Mac system:There is an option to show the hidden virtual keyboard. Click this menu to display the virtual keyboard that comes with your Mac system on your desktop.If you don't see or hide the virtual key

Solution 1: The direction keys and backspace keys cannot be used normally in ubuntu vi. in ubuntu, the direction keys cannot be used in the editing status, the return key cannot be deleted. Solution: You can install the vimfull version, in the full version... Solution 1: The direction keys and backspace

Eclipse shortcut keys, eclipse shortcut keys Ctrl + 1 quick fix Ctrl + D quick Delete Shift + enter skip this row and start the next row Ctrl + F11 quick run Alt + ↑/↓ move rows quickly Ctrl + Alt + ↑/↓ fast copy rows Ctrl + M window Maximization Alt +/Automatic completion Right-click the code area and select preferences → Java → editor → content assist → Auto activation triggers for java (automati

Differences Between Auto-incrementing primary keys of mysql Storage types and primary keys of mysql Storage Q: if there is a table with an auto-increment primary key whose field is id, after 10 data entries have been inserted into the table, the data with id and 10 has been deleted, restart mysql and insert a data record. What is the id of the data record, which is 8 or 11?A: If the table type is MyISAM, i

In the GIT management process, do not want to enter the user name and password every time, the solution is as follows;1. The link is replaced by the SSH protocol.2. Add the SSH public key to the GIT server.Open Gitbash1) Enter the command ssh-keygen-t rsa-c "XXXX" and then press ENTER, double quotation marks in the mailbox or username to change their own;2) Double Press 3 times Enter3) Copy the contents of id_rsa.pub (this file in the personal directory under the SSH folder) into the GIT server

Android ring menu (processed menu keys and return keys + added animations) Not much nonsense. first look at it: Package com. example. circlemenuofbottom. anim; import android. view. animation. rotateAnimation; import android. widget. relativeLayout;/*** @ author lzd *** QQ: 2622596982 *** email: www.bkjia.com ** QQ chat group: 277599214 */public class MyAnimationUtils {/*** exit animation --- cloc

Database Operations change primary keys, insert loops, and database primary keys-- Alter table HistoryData drop constraint PK_HistoryData -- delete the primary keyAlter table HistoryData add constraint PK_HistoryData primary key (CollectionTime, Code) -- change the primary keyDelete from HistoryData where CollectionTime between '2017-09-01 00:00:00 'and '2017-11-01 00:00:00' and ID not in (Select id from (S

Shift+ctrl+t: New tab pageSHIFT+CTRL+W: Close tabCtrl+pageup: Previous tabCtrl+pagedown: Next tabShift+ctrl+pageup: Tab Shift leftShift+ctrl+pagedown: Tabs Move RightALT+1: Switch to tab page 1ALT+2: Switch to tab page 2ALT+3: Switch to tab page 3Shift+ctrl+n: New WindowSHIFT+CTRL+Q: Closing the terminalCopy/paste in terminal:Shift+ctrl+c: CopyShift+ctrl+v: PastingTerminal change Size:F11: FullscreenCtrl+plus: Zoom InCtrl+minus: DecreaseCtrl+0: Original SizeLinux terminal shortcut

index-based update operation, although MyISAM may be inferior innodb, but so high concurrency of write, from the library can chase is also a problem, It might as well be solved by a multi-instance sub-Library table architecture.7, if it is used MyISAM, the merge engine can greatly speed up the development of the application department, they just do some select count (*) operation on this merge table, it is very suitable for a large project total of about hundreds of millions of rows of a type (