pros and cons of mongodb

of the Web.5.AJAX points of attention and applicable and non-applicable scenarios(1). Attention PointWhen Ajax is developed, network latency-that is, the interval between a user sending a request to a server to make a response-requires careful consideration. Not giving users a clear response, without proper pre-reading data, or improper handling of XMLHttpRequest, will make users feel delayed, which users do not want to see, but they do not understand. A common solution is to use a visual compo

the previous service-side code is now placed on the client), destroying the original standards of the Web. Ajax attention points and applicable and non-applicable scenarios(1). Attention Pointwhen Ajax is developed, network latency-that is, the interval between a user sending a request to a server to make a response-requires careful consideration. Not giving users a clear response, without proper pre-reading data, or improper handling of XMLHttpRequest, will make users feel delayed, which users

controlsMain advantages: Multi-level linkageCons: Display a field as much as possibleDropDownList control is generally used for multi-level linkage, such as the linkage of provinces and cities, the main point here is to set the field for DropDownList to display fields and values to display the field is:After binding, the results are as follows:To this point, we have analyzed the merits and demerits of the data-bound control of ASP. We only have a deep understanding of the characteristics of eac

, it is easy to appear background break2 The time cost of flattening pictures is increased, CSS sprites need to measure the exact position of each background unit by Photoshop or other tools when developing.3 Coding and maintenance time cost will increase, CSS sprites in maintenance, if the page background has a little change, generally will change this merged picture, if in the original place, and can only (best) add pictures, so that the image of the byte increases, but also to change the CSS.

ultra-fast interpreter written in C + +, which has another unique feature: You can download the engine and embed it in any application. The V8 JavaScript engine is not limited to running in a single browser. As a result, node. JS actually uses the V8 JavaScript engine written by Google and rebuilds it to be available on the server.node. JS Benefits:1, the use of event-driven, asynchronous programming for network services and design. In fact, the anonymous function and the closure feature of Jav

shared, which does not affect the program's operation, but it gives us code and trouble reading the program. In addition,spring3 MVC validation is also a bright spot, support JSR303, processing AJAX Requests is more convenient, just a note @responsebody, and then directly return the response text. Send the following code:[Java]View PlainCopy @RequestMapping (value= "/whitelists") Public String index (Modelmap map) { Account account = Accountmanager.getbydigitid (Securityconte

, theaccept method is synchronous, only when the user's request to come, will continue to execute down, Or else you'll be stuck here. Preferably with multi-threaded use, the front of the VC under the Chat tool when the communication part of a separate open a thread, the main thread continues to run to the layout interface. When there is data arriving, the message can be sent. AsynchronousAdvantage: thread does not snap to deathCons: trouble to take the proxy method so we generally use asynchrono

developers do not need to consider the logical structure of data, only the business data entities. Hibernate Disadvantages of:1 and inflexible . Since the operations are all objects, it is inconvenient compared to using traditional SQL statements. 3 and achieve complexity . and many complex query SQL statements are difficult to query with hibernate . Therefore, it is difficult for the program to be tuned. 3 , Big Data processing is slow . The transformation of the object model and the relationa

developed, network latency-that is, the interval between a user sending a request to a server to make a response-requires careful consideration. Not giving users a clear response, without proper pre-reading data, or improper handling of XMLHttpRequest, will make users feel delayed, which users do not want to see, but they do not understand. A common solution is to use a visual component to tell the user that the system is in the background and is reading data and content.(2). Ajax Application S

increasing the accuracy of quotations, speeding up the invoicing process and reducing the error rate of order management and invoicing. Logistics and Order FulfillmentNetsuiteerp The system improves your shipping efficiency, reduces logistics costs, and integrates seamlessly with top shipping companies like FedEx, UPS and USPS. Human Capital ManagementStreamline HR management processes with 24x 7 of self-service portals for employee time management, incentive compensation, expense reporting and

1. In IOS programming, there are several situations where multithreading is required: UI events must be performed on the mainline thread, others can be performed in the background, and tasks that are time-consuming or blocking threads are finally placed in the background line thread.There are several multithreading techniques for 2.iOS: threads, GCD, and Nsoperationqueue (Operation Queues).3. Threading this technique is more complex, but the thread has a later advantage: the ability to accuratel

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What is the CI framework? What are the pros and cons of yaf comparison?

The pros and cons of several mainstream PHP frameworks

is a very common way of JS use, often add a href= "# # #" That is without is to be compatible with multiple browsers to #是有特定意义的, if there is content behind the #, it will be considered a label, the corresponding tag will be found when clicked, and will jump to the first page when it is not found. The page is not refreshed. # # # #其实是 # and # #的组合, is a meaningless label, just a habit of writing, the principle "relies on the Web page error mechanism, can not be found to do not do".

intended to replace some simple tests. Use exceptions only in exceptional cases!2. Do not refine the exception excessively. Instead of adding exception handling on each statement, it's a good idea to put the entire task inside a try block. If one of the operations fails, you can discard the task immediately.3. Do not "suppress" the exception. For methods that need to advertise the exception, we can use the snapping method to force the exception to be closed, and if there is an exception, the ex

-(void) delay1{ // deferred execution do not use sleep, bad: stuck to the current thread [nsthread Sleepfortimeinterval:3]; NSLog (@ "-----Download Picture-----");}-(void) delay2{ // Once the delay task has been customized, the main current thread will not be jammed (which thread execution of the deferred task depends on where the current code is called) [ Self performselector: @selector (Download:) Withobject:@ "http://555.jpg" afterdelay: 3];}- (void) delay3{//3 seconds back

software platform. Capable of supporting up to 50,000 concurrent connections, thanks to Nginx for choosing Epoll and Kqueue as the development model.Nginx as a Load Balancer server: Nginx can either directly support the internal Rails and PHP programs outside the service, also can support as an HTTP proxy server external services. Nginx is written in C, which is much better than Perlbal, both in terms of system resource overhead and CPU efficiency.2, Nginx configuration is concise, Apache compl

Syntax sugar, equivalent to if (!! num = = false) Num=1; Java-like num=null? 1:numThe following is an answer from a friend who knows:It's just a shorthand method. The advantage is shorter, but in fact the disadvantage is even greater.Do you know exactly when it will become 1?-When NUM has a value of 0 o'clock, it will become 1!--When NUM has a value of Nan (which most likely means an error in the previous calculation), it becomes 1!--In addition, when the incoming value type is wrong, your progr

1. Get is the data that is fetched from the server and post is the data sent to the server.2. Get is the URL where the parameter data queue is added to the Action property of the submission form, and the value corresponds to the field one by one in the form, which is visible in the URL. Post is the HTTP post mechanism that places the fields within the form with their contents in the HTML header, along with the URL address referred to by the Action property. The user does not see the process.3. F