disadvantages of esop

previous site content. Because in the search engine database has not completely deleted the previous site all the data, so this need to give the search engine more time to recognize the new site. My friend's website listens to him to say that it is almost one months before beginning to collect. The old domain name to do a new station has a certain advantages and disadvantages, for its needs according to our actual situation, said here, hope to help

With the gradual deepening of network application, the Telecom class switch, especially the three-layer switch, has become the focus of the market contention. However, in different functions, a wide range of switch equipment, users how to remove the fog, to find their own application characteristics of the product? This not only requires users to start from the traditional switch evaluation indicators, consider the price of products, but also pay special attention to whether the product can prov

support the "IP Tunneling" (IP Encapsulation) protocol, the server may only be limited to some Linux systems. Iii. Direct routing mode (VS-DR) Principle: Both the Load balancer and RS use the same IP external service, but only Dr responds to ARP requests, all RS to the ARP request of itself this IP is silent that is to say, the gateway to the service IP request all directed to the DR, and Dr received the packet according to the scheduling algorithm, find the corresponding RS, To change the d

When you burn a data disc under Windows XP, you copy the file you want to burn to a mirrored drive, and then burn it as a mirror. This process may seem complicated, but Windowx XP has done all the preparation for us, so just add the file you want to burn by adding it to the list on the disc by copying-pasting, dragging and dropping the file or selecting the file. Here are two examples to illustrate the specifics of the operation and to explore the advantages and

this virtual printer in the "Devices and Printers" (Win7 system). When we need to convert the file, just open the converted file, then print the file, then select the printer, select the PDF virtual printer. In the process of conversion, you can also choose options such as quality, font embedding, and so on. The higher the quality, the clearer the result. The purpose of embedding fonts is to prevent them from appearing garbled when they do not have a corresponding font on the target

In general, the HTTP protocol is a stateless service, and it does not save any user request information. Web applications have been greatly developed until Netscape began using cookies to save user request information. Now asp.net programmers can save user request information in a number of ways. Here are a few ways to ASP.net about client state management. asp.net, which provides cookies, querystrings (URL), Hidden fields, View State and control state (ASP.net 2.0), manages client requests.

with transaction semantics in bean code. In both cases, the container manages the transaction and determines whether the given transaction should be committed. 5, based on the components of the design. Entity beans are designed to contain components that are configured with deployment descriptors and can be deployed to any Java EE application Server without changing any code. In summary, the advantage of entity beans is that they can benefit from standardization and industry best practices, s

Stored Procedures | Encapsulation SQL Server 2005 can write stored procedures in. NET languages, so in small and medium applications, it becomes a good choice to use the stored procedure encapsulation application logic. The advantages of using stored procedures to encapsulate application logic are as follows: 1, Dba+developer Division of labor Clear. Code modularity between. Reduce database operator and programmer errors. 2. Database security; You can set the account in the connection string

; try {//Load Database driver Class.forName ("Com.mysql.jdbc.Driver"); Get the database link through the data-driven management class connection =drivermanager.getconnection ("Jdbc:mysql://localhost:3306/mybatisdata?characteren Coding=utf-8 "," root "," root "); Define SQL statements, where? Identity placeholder String sql = "SELECT * from user where id =?"; Get preprocessing statement preparedstatement = connection.preparestatement (sql); S

that the composite column length cannot be too long; In a composite index, all columns must be from the same table, and composite columns cannot be created across tables In a composite index, the order of the columns is very important, so the order of the columns is carefully arranged, in principle, the most unique column should be defined first, for example, the index on (col1,col2) is not the same as the index on (col2,col1), because the order of the two-indexed columns is different ; for the

composite index, the total length of the columns that make up the composite index cannot exceed 900 bytes, which means that the composite column length cannot be too long; In a composite index, all columns must be from the same table, and composite columns cannot be created across tables In a composite index, the order of the columns is very important, so the order of the columns is carefully arranged, in principle, the most unique column should be defined first, for example, the index on (col1

Summary of advantages and disadvantages of ORACLE five tables:1, Normal table (heap table): Suitable for most design scenarios, there are advantages and disadvantages.Advantages:A, the syntax is simple and convenientb, suitable for most scenesDisadvantages:A, the update log cost is largeB,delete Cannot free space (HWM high water mark does not drop)C, table record too large retrieval too slowD, index back table read overheadE, even if inserted in order

the gender column of the personnel table, in the results of the query, the data rows of the result set occupy a large proportion of the data rows in the table, that is, the data rows that need to be searched in the table are large. Increasing the index does not significantly speed up the retrieval. Third, for those columns defined as text, the image and bit data types should not be indexed. This is because the amount of data in these columns is either quite large or has very little value. The i

the form of a two-dimensional table! a two-dimensional table is made up of rows and columns, knowing that the row and column numbers will be able to locate the data in the table! Excel is a two-dimensional table! Easy to use, the basic common SQL language makes it easy to operate relational databases! SQL is supported , so complex queries can be made! easy to maintain, rich integrity (domain integrity, entity integrity, referential integrity, and custom integrity) greatly reduces data redun

exceed 900 bytes, which means that the composite column length cannot be too long; In a composite index, all columns must be from the same table, and composite columns cannot be created across tables In a composite index, the order of the columns is important, so the order of the columns is carefully arranged, in principle, the most unique column should be defined first, for example, the index on (col1,col2) is not the same as the index on (col2,col1), because the order of the two-indexed colum

This article focuses on the details of Ajax, the origin of Ajax, the principle of Ajax, and the advantages and disadvantages of Ajax. Now let's see this article together. What is Ajax In fact, Ajax already belongs to the old technology, and now almost no one will use, here is mainly the bottom of the things to share with you, in case of loading the interviewer. Ajax, "Asynchronous JavaScript and XML" (Asynchronous JavaScript and XML), refers to a web

created, it waits for the first time to execute. At that time, the stored procedure was optimized, and the query plan was compiled and cached on the system. When you run the stored procedure several times, the cached query plan is used instead of creating a new query plan, unless specified by using the WITH RECOMPILE option. This means that each time the stored procedure is used, the stored procedure skips a lot of optimizations and compilation work. The exact time to save depends on the comple

version determines the stability of the RAC operation. It is important for database engineers and hardware engineers to have extensive environmental checks, validations, and extensive testing after deployment before installing the configuration.　　Second, high-performanceHigh performance is also a major headache for migrating from a single machine environment to a RAC environment, and RAC is not a high-performance solution. In the current hardware environment of gigabit Network, many times the s

complexity of the application index-ready file is O (n).C) Poll use Nfds to specify the maximum number of file descriptors and events to listen to, this number can reach the system agreed to open the largest file description of the descriptor. That is, 65535.D) can only work in the LT mode.3) Epoll:A) epoll the file Description descriptor and events of the user's booklet into the event table in the kernel. Provides a stand-alone system call Epoll_ctl to manage user events, and epoll the way cal

Label:The benefits of a relational database:1. Maintain data consistency (transaction processing)2. Due to standardization, the cost of updating data is small (the same fields are basically only one place)3. Complex queries such as joins can be madeOne of the best advantages of relational databases is the ability to maintain data consistency.The lack of a relational database:Not good at handling1. Write processing of large amounts of data2. Index or table structure (schema) changes for tables wi