mongodb advantages

MyISAM table, not a ISAM table. 3, dual-machine hot backup. There is no mechanism for an incremental backup of the MySQL database. Backup is a big problem when the amount of data is too large. Fortunately, the MySQL database provides a master-slave backup mechanism (that is, hot standby) Advantages: When the data volume is large. Now I get it. Large Internet companies for MySQL data backup, are using a heat engine backup. Set up a number of data

implementation of LINQ to SQL is based on ado.net and c#2.0. It translates the SQL statement automatically and creates the result set as an object and returns. Here we can see that the SQL statements sent to the SQL Server side are generated automatically by LINQ to SQL. This is no doubt a boon to those who do not know SQL. Second, LINQ to SQL statements are checked during compilation. Rather than run-time checks. In this way, there is a problem and can be changed in time, rather than at runtim

When we format a USB disk, we can see three options in the Format option, are "Quick format", "Enable compression" and "Create a DOS boot disk", most of the time we choose to format quickly, very few people use the back two, today we will give you a specific introduction to the "Enable compression" option. Look at what it does and what the pros and cons are. Enabling compression is NTFS-formatted to compress the disk (compress the files inside your hard drive to save hard disk space).

exFAT (Extended file allocation table file System, extended fat, also known as Fat64, extended file allocation table), is designed to address FAT32 and other files that do not support 4G and larger, for flash memory, The NTFS file system is not suitable for use, and exFAT is more applicable. The EXFAT format is a format that Microsoft has specifically tailored for u disk, and the exFAT format is a tradeoff between FAT32 and NTFS, with FAT32 portability, no need to wear too much performance and

Method One : Modify the server.xml fileAdvantages :Configuration is fast, just add tags to the server.xml file , where you configure the path virtual path and docBase the real path and start the Tomcat ServerDisadvantages :Need to configure two paths if path is an empty string, default configurationRestart the Tomcat server after each modification of the server.xml file , redeployMethod Two : create a virtual host under the Catalina folder and configure the virtual hostAdvantages :Configure th

the efficiency.But between security and efficiency, the first thing to consider is security. The premise of synchronization one, multiple threads to perform the time required synchronization, if it is a single thread does not need synchronization. More than one thread is using the same lock during execution. If it is, it is synchronous.Otherwise, it is not synchronized. Synchronzied (obj) {} The same synchronzied (new Object) {} is not the same lockSynchronize the code that needs to be synchron

speed than the single-server mode speed can be faster.E) low cost: different from the HTTP mode, the server does not necessarily put a high-quality computer room, can only a small number of room. Many servers can be used in the United States low-cost servers, 1G bandwidth one months on more than 1000 yuan, this price seconds to kill a lot of domestic computer room. Before 2008, I also saw someone renting some houses and putting on some ordinary computers to do peer-to speed. Especially looking

1, can be indeterminate length, according to the actual need to add elements, can save space, and better solve the real problem. Arrays are fixed-length when initialized, and cannot be changed.2. The collection can add elements of any type, and the array must be of the same type.3, the collection can be achieved by the equals and Comparto methods to customize the comparison criteria of elements, to achieve any type of element comparison.4, the collection also has a lot of features, can solve mor

Advantages of DIV+CSS1, in line with the standard. This ensures that your site will not be phased out for future upgrades of your Web applications.2, more affinity for viewers and browsers. Because CSS is rich in style, making the page more flexible, it can be based on different browsers, and achieve the unity and non-deformation of the display effect. This supports browser backwards compatibility, which means that whatever the future of the browser w

());//true Console.log (false); Isboolean Console.log (isstring (1));//false Console.log (IsError (1));//false Console.log (New Error ()); IsError Console.log (iSarray ([]));//true Console.log (IsArray (1));//false The code above implements IsNull, isundefined, Isboolean, Isnumber, isstring, Isfunction, IsArray, IsDate, Isregexp, IsObject, IsError these 11 detection functions. The type function is also implemented to detect the data type. Console.log ({});//"Object" Console.log (Typ

allows subclasses themselves to decide at runtime, but because the creator Clas S is written without knowledge of the actual products that'll be created, which are decided purely by the choice of the S Ubclass is used. What are the advantages of the factory method model?： Good encapsulation, the structure of the code is clear. An object creates a conditional constraint, and if a caller needs a specific product object, it is OK to know the class nam

an error before declaring the variable. Because the actual effect of these two lines of code is: var a;console.log (a); A = ' Hi '; When parsing the JS code, the variable's declaration hint to the start position, this way is also more confusing Use let after, there is no this problem, will directly complain Console.log (a); Uncaught referenceerror:a is not definedlet a = ' Hi '; Performance to do a simple test var start = + new Date (); for (var i = 0;i

operation class from beginning to end, Apache provides us with a powerful log-handling package-log4j.Log4j is an open source project for Apache, by using log4j, we can control the destination of log information delivery is console, file, GUI component, even interface server, NT Event recorder, UNIX syslog daemon, etc. We can also control the output format of each log, and by defining the level of each log information, we can control the log generation process more carefully. Most interesting of

The usage and advantages and disadvantages of anonymous function in JS Anonymous functions are effective in ensuring that JavaScript is written on the page without causing global variables to be contaminated.This is very effective and graceful when adding JavaScript to a page that is not very familiar. One, what is the anonymous function. There are generally three ways to define a function in javascript: Functions keyword (function) statement:functi

action is taken on the values in a and b memory, which means that you are working on another two separate memory spaces that are not associated with a and b, so naturally you cannot swap the values of A and B. So why is the first method possible? Since the F () function is invoked at this time, the incoming formal parameter is a and b, so that is to say x=a,y=b, then obviously *x and a are a concept, and the operation *x and *y are actually the * (a) and * ( b), so when swapping *x and *y, the

DatabaseType Characteristics Advantages Disadvantages relational databaseSQLite, Oracle, MySQL 1, relational database, refers to the use of a relational model to organizeDatabase of data;2, the most characteristic of relational database is the consistency of affairs;3, in simple terms, the relational model refers to the two-dimensional table model,A relational database is a data organization composed of two dimensional tabl

The pointer is the C language only so successful one of the important reasons, of course, anything, is often a two-sided, essentially one, looks is both sides, the key is to ingenious, not more than the distinction between advantages, disadvantages. C language is mainly for the hardware and system of the underlying programming, in the hardware and system-level programming, the flexibility of the data requirements, in other words, the meaning of the d

Now many websites have used the div+css to layout the webpage structure, the advantage is the speed is fast, may the negative influence, see below analysis Front-End time to write a "use of CSS framework for efficient site development", a lot of friends asked me related questions. Very early 5key in the company for the framework of CSS frameworks, but also to many friends of the proposed CSS framework. The effect is very obvious. Of course, the CSS framework has

Increase the advantages and disadvantages of the mainstream mode of the outside chain Statistical tools are not just to see how many people today, but to see how people come, have seen what to do, the site clicks the largest number of what, and so on. A good seoer must be a good analyst who sees "truth" from the data. Individuals are just trying to look at the data, there are several aspects of the feeling is worth noting. One is IP and PV, mainly t

the statistics on memory consumption**※ but also notice that the difference in the unit is milliseconds,* I just want to show that generics are good,* But do not excessively pursue the merits of the procedure,* In short, to grasp this degree, for their own is the best* O (∩_∩) o~*/Console.read (); Advantages and disadvantages of ArrayList and LinkedList Java programming We use the most of the several classes can be string,arraylist,hashm