Mobile development: First intimate Contact Mobile database

The concept of mobile databases may have been unheard of by many people five of years ago. But now, its specific application has been very extensive. Readers who have just come in contact with this concept may wonder, what is a mobile database? Simply put, data is not stored purely on a server or PC, and can be stored in memory and on mobile devices with limited performance. The systems that are installed on mobile devices and used to manage and manipulate data are so-called mobile databases.

In many cases, you need to store some data on your mobile device. In the mobile database before the birth, all the data are stored in the file, when the amount of data is large, the data retrieval, delete operations such as the efficiency is very low. Now many companies take into account the diversity of mobile devices, XML is generally used to save data, although XML is a platform-independent document standard, but because of the current mobile device processing capacity constraints, so parsing a more data-containing XML files, the performance of the cost is not meet the actual requirements. The mobile database can be referred to as a database, that is, mobile databases may contain the amount of data can reach a considerable degree of scale, rather than a small amount of data (dozens of or hundreds of records) can be compared.

In this topic, two focuses will be launched: One is Microsoft's mobile database-sql Server, the Edition Compact. The other is "developing a mobile version of the data management system using the. Net Compact framework". It is hoped that this topic will enable readers to become more proficient in the development of mobile data management systems.

Application of Mobile Database

Does it make sense to place a mobile database on a mobile device? I believe a lot of people will have this kind of doubt, and there are a lot of development experience programmers heard the author in the application of mobile database development system, is also very incredible. However, you can further consider that if information can be improved to be portable and easy to carry, it will have the following benefits:

1. Reduce the load on the hub server

Most of the current system needs the front-end program from the central server database to obtain data information, if there is a large number of access requests, the central server will be in a very busy state, this time will have a performance bottleneck problem. To this end, Microsoft has proposed the concept of intelligent client, so that the program can be offline, can also operate in the networked state. If we can save some of the data in the central server database to the mobile database, so many function implementations can be done directly on the mobile device, greatly reducing the load and pressure of the central server.

2. Information can be obtained at any time

When you're out of the house and the network is disconnected, we can store some data in a mobile database in advance. When needed, you can directly query the mobile database to store the data to obtain the appropriate information. When the network is connected, we can also load the latest information from the server to the mobile database, or transfer the data changes in the mobile database back to the server. Here are a few scenarios where information can be obtained at any time:

2.1 Industry Solutions

At present, according to the characteristics of various industries, many companies have adopted to meet the needs of their outdoor staff industry solutions. For example, just enter the Chinese market, a courier company is using a set of mobile solutions. Postmen at the beginning of a day's work, you can directly through the PDA to see all the packages that will be sent today, such as the package of the recipient, the address and contact information, and can also give an optimal delivery route. In addition, when the package delivery, customers can also directly on the PDA to confirm the delivery of goods, and then postmen can be customer signature and delivery of goods directly through the wireless network to the central server, to avoid a series of "paper operation" process, greatly accelerated the efficiency of the work.

Now many government departments are also gradually adopting wireless solutions to improve efficiency. For example, the Beijing government's many departments have used mobile Office system, no matter when and where, through the mobile Office system can deal with document approval, personnel management, performance audit and other management, effectively solve the business trip, meetings and other delays, and greatly improve the efficiency of the office. In addition, the department can be sent by SMS location, group sent in the form of meeting/event notifications, scheduling reminders, mail/document flow reminders.

2.2 Traffic Route inquiry system

In Beijing, Shanghai and Guangzhou and other big cities, transportation is a very big problem. If we can save the traffic route information of a certain city to the mobile database, we can check the bus route conveniently with the mobile device when we travel later. If you develop this type of program, you can use different implementation methods according to different requirements. The simplest way to save all of the city's route information to a mobile database is the lack of flexibility to get the latest route information in real time when some of the city's routes change. Of course, we can also retrieve information from the central database through the network and then store it in the mobile database, which not only can have better real-time, but also reduce the cost of multiple networking.