Source: http://bbs.bccn.net/thread-363932-1-1.html
Recently used C # to the database operation is a bit of a fan, do not understand the Acceptchange method and update methods, sometimes with the Acceptchage method after the record is submitted with the Update method update, the result database does not have any action. Confusing and later understood that the Acceptchange method simply changes the state of the corresponding DataRow, and any DataRow objects that are still in edit mode will success
database, another transaction accesses the data and then uses the data. Because this data is not yet submitted data, then another transaction read the data is dirty data, the operation based on dirty data may be incorrect. For example, an editor is changing an electronic document. During the change process, another editor copies the document (which contains all the changes made so far) and sends it to the intended user. After that, the first editor decided that the current changes were wrong, a
I. BACKGROUND
The cloud trend in the second half of 2012 began to provide a large state-owned bank's historical transaction data backup and query technology solutions based on Hadoop, due to the industry's particularity, customer service availability has a very high demand, and HDFs has long been a problem with the point of trouble, until Apache Hadoop released its 2.0 alpha version in May 2012, where MRv2 is still immature, and HDFs new features are already largely available, especially the hi
file to the Tomcat server automatically
3) Add all Geoserver-2.11.0-vectortiles-plugin.zip jar packages to XXXX and reboot Tomcat to complete the vector tile plugin loading
4) In the browser access, Localhost:8080/geoserver, if you open the following interface, the GeoServer installation is considered successful
Installation Note You can also install the "install version" GeoServer, can provide login settings and other parameters set permissions for the decompression version of the GeoServer, t
. If the second editor can make changes after the first editor finishes, you can avoid the problem. 2. dirty reading means that when a transaction is accessing the data and the data has been modified, and the modification has not yet been committed to the database, another transaction accesses the data and then uses that data. Because this data is data that has not yet been submitted, the data that is read by another transaction is dirty, and the operation based on dirty data may not be correct.
. If the second editor can make changes after the first editor finishes, you can avoid the problem. 2. Dirty reading means that when a transaction is accessing the data and the data has been modified, and the modification has not yet been committed to the database, another transaction accesses the data and then uses that data. Because this data is data that has not yet been submitted, the data that is read by another transaction is dirty, and the operation based on dirty data may not be correct.
scenarios can be controlled by two system variables:
The Optimizer_prune_level variable tells the optimizer to skip some scenarios based on an estimate of the number of rows accessed per table. Our experiments show that this type of "based guess" rarely misses the best scenario and can significantly reduce the number of query edits. This is why this option is on (optimizer_prune_level=1) by default. However, if you think the optimizer missed
bash information dedicated to your bash shell, which is read when you log in and every time you open a new shell.pash How to set environment variables:Method One: Use the. Profile or. bashrc file in the home directory (recommended)Log in to your user (non-root) and enter in the terminal:$ sudo gedit ~/.profile (or. bashrc)The following settings can be added to the path at the end of this file:Export path= "$PATH: Your path1:your path2 ..."Save the file, log off and log in, and the variable take
Vim Editor Our computer's editor is divided into two categories1, Text editorThe text editor edits the pure ASICLL document without any extra modifiers2, Word ProcessorWord processors include Word documents, word processing tools inside WPS, with many modifiers, but modifiers are not related to file content, but modifiers are an effective part of document data.One of the important philosophical ideas of Linux: Use plain text files to save configuratio
Pash How to set environment variables:Method One: Use the. Profile or. bashrc file in the home directory (recommended)Log in to your user (non-root) and enter in the terminal:$ sudo gedit ~/.profile (or. bashrc)The following settings can be added to the path at the end of this file:Export path= "$PATH: Your path1:your path2 ..."Save the file, log off and log in, and the variable takes effect.Variables added in this way are valid only for the current user.Method Two: The profile file under the sy
their own use, which is executed only once when the user logs on. By default, he sets some environment variables, Executes the user's. bashrc file./ETC/BASHRC: Executes this file for each user running the bash shell. When the bash shell is opened, the file is read.~/.BASHRC: This file contains bash information dedicated to your bash shell, which is read when you log in and every time you open a new shell.Pash How to set environment variables:Method One: Use the. Profile or. bashrc file in the h
To open multiple files:1.vim has not started yet:Enter in terminalVim file1 file2 ... filen can open all the files you want to open2.vim has startedInput: Open FileA file can be opened again, and the contents of the file will be displayed in Vim at this time.: E.. /myfile.pl1. Vim Document name Open document in normal way2. Vim +n document name after opening the document, position the nth row3. Vim, after entering the Vim interface, use the command: E document name to open the document, this way
Setting Commands is simple
The code is as follows
Copy Code
echo "Export Editor=/usr/bin/vim" >>.BASHRC
Then reopen the terminal, input crontab-e, found that the default vim has been used.
Linux under the VIM command detailed
: QX starts recording macros and stores the results in register XQ Exit Record mode@x play the Macro command recorded in the X registerTo explain a little bit, when you enter in normal mode: QX, all your
changes after the first editor finishes.
2, unconfirmed dependencies (dirty Read)
An unconfirmed dependency problem occurs when the second transaction selects rows that are being updated by another transaction. The data being read by the second transaction has not been confirmed and may be changed by the transaction that updated the row.
For example, an editor is changing an electronic document. During the change process, another editor copies the document (which contains all the changes made
Frontpage
Microsoft Office FrontPage 2003 has an improved authoring environment, new graphics capabilities, powerful coding tools (to help you apply and add a variety of coding language knowledge), and tools to help you create interactive scripts. In addition, FrontPage 2003 can generate efficient and clean HTML, allowing you to better control your code.
Web Page view
You can work with Web pages in any of the following page views:
Design view designs and e
at the beginning of the lineA append mode, placing the cursor after the current cursorA Append mode with cursor at end of lineo Add a new row below the current line and enter insert modeO Add a new row above the current line and enter insert modeESC Exit Insert Mode
11. Visual mode, tagged textV into visual mode, single character modeV into visual mode, row modeCTRL + V into visual mode, column mode, similar to UE column modeo Jump cursor to another endpoint of the selected blockU turn the cont
Dreamweaver
Fireworks recognizes and retains most of the types of edits made to documents in Dreamweaver, including changed links, edited image maps, edited text and HTML in HTML slices, and behaviors that are shared between fireworks and Dreamweaver. The property panel in Dreamweaver helps you identify the images, table slices, and tables that fireworks generate in your document. Here's a look at the table and the image edit separately.
1. Edit Fir
the data of the database inconsistent, Then the data read by T2 is "dirty" data, that is, incorrect data. For example, an editor is changing an electronic document. During the change, another editor copied the document (which contains all the changes made so far) and distributed it to the intended user. After that, the first editor thought the changes were wrong, and then deleted the edits and saved the document. Documents that are distributed to use
data that has not yet been submitted, the data that is read by another transaction is dirty, and the operation based on dirty data may not be correct. For example, an editor is changing an electronic document. During the change, another editor copied the document (which contains all the changes made so far) and distributed it to the intended user. After that, the first editor thought that the changes that were being made were wrong, and then deleted the edi
To open multiple files:1.vim has not started yet:Enter in terminalVim file1 file2 ... filen can open all the files you want to open2.vim has startedInput: Open FileA file can be opened again, and the contents of the file will be displayed in Vim at this time.
: E.. /myfile.pl
1. Vim Document name Open document in normal way2. Vim +n document name after opening the document, position the nth row3. Vim, after entering the Vim interface, use the command: E document name to open the document, this w
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