mongodb 2 6

: In replica sets, primary must be able to communicate with the majority of nodes in the cluster to avoid the formation of two or more nodes in different groups due to network disconnection, this will affect data consistency .) 2. About downgrade Some problems may occur when the node is downgraded from primary to secondary. In MongoDB, write operations are performed in the fire-and-forget mode by default,

update operation, and the insert operation reports an error. Delete all data in the list Db. persons. remove () delete data in persons but do not delete the index (db. system. indexes. find () has a value) For Db. person. drop () will delete the index Delete Db. persons. remove ({_ id: "3 "}) If you want to clear a collection with a large amount of data, it is much more efficient to directly Delete the set and re-index it. 1. Tough Document Replacement update operations Update > Db. persons

1. In JavaScript, the arguments object is a more specific object, which is actually a built-in property of the current function. Arguments is very similar to an array, but is not actually an array instance. Can be confirmed by the following code (of course, in the function Funcarg, the call arguments is not necessarily written funcarg.arguments, write arguments directly).1 ARRAY.PROTOTYPE.TESTARG = "Test"; 2 function Funcarg () {3 alert (FUNCARG.A

previous element. Let's do this on the script division above: Steps Stack Script Description 1 Empty 5 2 OP_ADD 7 OP_EQUAL The first stack is empty 2 5 2 OP_ADD 7 OP_EQUAL Take it out of the script and 5 put it on the stack 3 5 2

: $ ("tr: first"); returns a collection of individual elements. Description: matches the first element found. 2.: lastUsage: $ ("tr: last") return value set Element Description: match the last element found. It corresponds to: first. 3.: not (selector)Usage: $ ("input: not (: checked)") return value set Element Note: Remove all elements that match the given selector. It is a bit similar to "Non", meaning that the input is not selected (when the input

Label:Mongodbtags (space delimited): Database MongoDb InstallationCurrent version 2.X Extract to any directory, it is best not to beCPlate. Create a folder in the root directory to store the project My example: Install to:D:\mongodbCreate a storage directoryD:\mongodb\blogRunCmdCutBinDirectoryCD D:\mongodb\bInch

1, memory management Simple Introduction1, why should I have memory management? malloc selloc dealloc ' need to go back to reviewThe general memory 4s is 512m memory; 6 is 1024m memory;When memory is too large, memory is exhausted. There is a program flash back.2, OC Memory Management range:Manages any inherited NSObject objects that are not valid for other basic data types.3, the object type is dynamically

Today, a new MVC project was created with VS2015. The error CS1617: Option "6" is invalid for/langversion; must be ISO-1, ISO-2, 3, 4, 5, or DefaultSee the detailed error message below (note the red text: /langversion:6)C:\Program Files (x86) \iis express> "C:\Windows\Microsoft.NET\Framework\v4.0.30319\csc.exe"/t:library/ UTF8OUTPUT/R: "C:\Users\lizhaoyang\AppDat

11-3. Returns a computed column for a "model definition" functionProblemTo return a computed column from the model definition functionSolution SolutionsSuppose we have an employee entity with attributes: FirstName, LastName, and birthdate, such asFigure 11-3.Figure 11-3. An Employee entity with a few typical propertiesWe want to create a "model definition" function that returns the merged full name of FirstName and LastName. We want to create another model definition function that returns the ag

Original article: http://blog.sina.com.cn/s/blog_48a770da0100gam5.html Rare and rare Chinese Drupal view detailed tutorial, transferred from http://www.cc.ntu.edu.tw/chinese/epaper/0009/20090620_9009.htm Author: programming organization for Educational Research Groups at Tang xuanyuan university computer and network-based Education Center In this article, we will introduce?The large functions and usage of arguments, relationships and sort criteria in. Connect to modules... use Drup

void onhello (); 3) before end_message_map () in mainfrm. cpp, add On_command (idm_hello, onhello) // Do not add it in the middle of the default one; otherwise, the system may kill it without knowing it. 4) Add the cmainframe: onhello () function definition to mainfrm. cpp. // Tips: Add a waste, imitate it, and delete mock... 4. Add/delete menu items to/from the System Menu Getmenu ()-> getsubmenu (0)-> appendmenu (mf_string, 114, "welcome "); Getmenu ()-> getsubmenu (0)-> insertmenu (id_file_o

This post was last edited by Lscxp on 2013-08-29 18:18:23 Reference PHP $a = 2; $b = $a; Echo (+ + $a) + ($a + +); This is 7. $a = 2;echo (+ + $a) + ($a + +); The answer is 6. But that $b is useless from beginning to end, why is the answer different after adding a line? Reply to discussion (solution) Look at this.http://bbs.csdn.net/topics/39

Data Structure interview 6-common operations of binary tree 2 (Non-recursive Traversal Binary sorting tree) Note: The interview book has related exercises, but the ideas are relatively unclear and the layout is incorrect. The author has rewritten the related books and opinions for your reference. 6. Basic Binary Tree operations (non-recursive traversal) Binary

Android note 6. deep understanding of Intent and IntentFilter (2)Deep understanding of Intent and IntentFiler (2) Jiangdg_VIP Http://blog.csdn.net/u012637501In the previous article, we learned more about Intent. Now we will learn how to set these attributes of Intent objects and how to use them to start components. An Intent object is a set of information. We can

processed template display, where the template file does not add the path, as long as the use of a file name, it is the path we have already defined in $smarty->templates (Stringpath).After the execution of the program we can open the current directory of the Templates_c and the cache directory, we will find a few more than a few percent of the directory, these directories are smarty compilation and cache directory, it is automatically generated by the program, do not directly modify these gene

is very little Chinese Information on the SIP network. I am still a technician with poor English skills. To help more people understand the SIP protocol and study the SIP protocol, I have such a bold idea. The original text of this translation is rfc3261. Due to my English proficiency, I use literal translation for the document. Of course, I have a personal understanding between the lines. please correct me for any improper content. In addition, the source must be reprinted. Please do not use i

Title: If a number is exactly equal to the sum of its factors, this number is called the " end number ". For example 6=1+2+3. Programming Find out All the numbers within the range. 1 Packageday11_2;2 3 Public classlianxi09 {4 Public Static voidMain (string[] args) {5 6 for(inti = 1; i ) {7 intSum=0;8 for(intj =

6-11.Conversion.(A) Create a conversion from an integer to an IP address in the following format: www. xxx. yyy. zzz.(B) Update your program to enable reverse conversion.[Answer](A) The Code is as follows:Input_number = abs (int (raw_input ('Please input a number ...')))X3 = x2 = x1 = x0 = 0X3 = Input_number/(256 ** 3)If x3> 255:Tmp = x3X3 = 255Else:Tmp = x3X2 = (Input_number-256 ** 3 * tmp)/(256 ** 2)X1 =

Package com. WZS;/*** title: If a number is equal to the sum of its factors, this number is called "end number ". For example, 6 = 1 + 2 + 3. Program to find all the completion numbers within 1000. ** @ Author administrator **/public class test_wzs9 {public static void main (string [] ARGs) {test_wzs9.f ();} /*** final number */public static void F () {for (INT I = 1; I Output result:

download and install a new database driver.Step 6: Run the Confluence Setup Wizard and copy your data into the new databaseWhen you run the Confluence Setup Wizard: Enter your license key as usual. Select Production installation (Production installation) in the installation type. Select my own database from the data type drop-down menu (my own databases) Then select the database you are using for installation.