Compare Tables In Two Different Databases

The concept of blockchain to technology has been around for a long time, but with the heat of the past two years, it has gradually become known by the market and many technicians.

1.1: Increase the secondary data file from SQL SERVER 2005, the database does not default to generate NDF data files, generally have a main data file (MDF) is enough, but some large databases, because of information, and query frequently, so in order to improve the speed of query, You can store some of the records in a table or some of the tables in a different data file. Because the CPU and memory speed is much larger than the hard disk read and write speed, so you can put different data files on different physical hard drive, so that the execution of the query, ...

A good database product is not equal to have a good application system, if can not design a reasonable database model, not only will increase the client and Server section program programming and maintenance of the difficulty, and will affect the actual performance of the system. Generally speaking, in an MIS system analysis, design, test and trial run stage, because the data quantity is small, designers and testers often only notice the realization of the function, but it is difficult to notice the weak performance, until the system put into actual operation for some time, only to find that the performance of the system is decreasing, At this point to consider improving the performance of the system will cost more ...

It is well known that query optimization is an unavoidable topic in any database. For database engineers, optimization is the most challenging job. MySQL Open source database is no exception. In fact, the author believes that the database optimization is not as much as we imagine the suffering. 　　Under normal circumstances, you can start from the following four details to do a good job in the MySQL database query optimization. First, use the Explain keyword to evaluate the flaw in the query statement as shown in the following figure, now the author in the database to execute a simple select ...

Cassandra and HBase are the representatives of many open source projects based on bigtable technology that are implementing high scalability, flexibility, distributed, and wide-column data storage in different ways. In this new area of big data [note], the BigTable database technology is well worth our attention because it was invented by Google, and Google is a well-established company that specializes in managing massive amounts of data. If you know this very well, your family is familiar with the two of Cassandra and HBase.

With the proliferation of data volume, Mysql+memcache has not met the needs of large-scale Internet applications, many organizations have chosen Redis as its architectural complement, however, redis the use of the threshold is not low, such as not supporting SQL, here for everyone to share the Redis use of the full raiders. Redis, one of the most closely watched NoSQL databases, has been used by many well-known internet companies, such as Sina Weibo, Pinterest and Viacom. However, being born with no support for SQL makes him look difficult ...

After more than eight years of practice, from Taobao's collection business to today to support all of Alipay's core business, and in the annual "Double Eleven Singles Day" continue to create a world record for the transaction database peak processing capacity.

PaaS (Platform-as-a-service) is a kind of cloud service, the service provider not only provides on-demand hardware and operating system services, but also provides the application platform and solution stack. For developers, PAAs greatly reduces the cost and pain of it deployments, providing resources for applications to scale more easily as needed. JVMs, application servers, and deployment packages (for example, war and ear) provide natural isolation for Java applications, allowing different developers to deploy applications in the same infrastructure, so JAV ...

Intermediary transaction SEO diagnosis Taobao Guest Cloud mainframe technology hall with the advent of the 11 long holiday, everyone to the Ministry of Railways 12306 of the discussion again. This article (original) from 12306 website extension to the site performance of a lot of discussion, for entrepreneurs and technology enthusiasts have a strong reference. 　　The author Chenhao (Weibo) has 14 years of experience in software development, 8 years of project and team management experience. 12306.cn website Hung, was scolded by the people all over the country. I've been here for two days.

The purpose of data mining is to find more quality users from the data. Next, we continue to explore the model of the guidance data mining method. What is a guided data mining method model and how data mining builds the model. In building a guided data mining model, the first step is to understand and define the target variables that the model attempts to estimate. A typical case, two-dollar response model, such as selecting a customer model for direct mailing and e-mail marketing campaigns. The build of the model selects historical customer data that responds to similar activities in the past. The purpose of guiding data mining is to find more classes ...