Microsoft Data Engine (MSDE) bis

Data MSDE Summary

If developers want to create desktops or shared database applications, and plan to expand the functionality and scale of these database applications in the future, using MSDE as a data engine will have the following advantages: In the near term, the development costs of the system can be reduced, and in the long run, also provides the most convenient way to migrate a database application that is currently created. When the size of your organization expands to provide new requirements for the functionality and performance of your database system, you can completely migrate it to a SQL Server based platform without modifying any of the code in your existing database application. In addition, because MSDE is fully compatible with SQL, developers can use the same data access language to seamlessly transform between relatively small MSDE database systems and larger SQL Server database systems.
Under what circumstances do you choose Jet
For some special database systems, it is also a good choice to use Jet 4.0 as the engine. In this section, we will discuss under what circumstances jet should be selected as the database engine.
Distribution of
In a database system that uses Jet as an engine, it is easy to back up and publish a database because the database is contained in a separate file. While the database system is running, other files access the Jet database files through applications such as visual Basic or Microsoft access, but because developers have a good definition of the dependencies between these files, Accessing database files does not take up a large amount of storage space on the system or use large amounts of processor resources. MSDE databases are more difficult to publish and install than the Jet database. Therefore, if you want to simplify the process of publishing and installing the database, it is a good choice to choose jet as the engine for the database.
Development costs
Developers can publish a database based on Jet 4.0 with a database application developed with the following tools:
* Microsoft Office 2000
* Microsoft Access 2000
* Related tool components in any version of Visual Studio 6.0 (these components are listed in the previous section of the article)
If development costs are an important factor to consider when creating a database application, it is a good choice to choose jet as the data engine.
Scalability
Both MSDE and Jet databases can be run in the desktop and in shared database applications. For some database applications, the amount of data they handle may never exceed 2GB, and the number of users supported will not exceed 20. If you have a Jet database application, and even as the system grows, it does not handle much of the data and needs to support enough users, then it is still a good choice to use jet as the engine of an existing database.
Requirements for system resources
Because the Jet database is compressed, it is appropriate to choose jet as the engine for the database on those platforms with limited resources. Of the three data engines discussed in this article, the database with Jet as engine consumes the least amount of storage space and system memory consumed. If you use a machine that has very limited disk space or system memory, it would be wise to choose jet as the engine.
Compatibility with previous versions
Jet 4.0 provides maximum compatibility for those databases that are based on previous versions. You can run multiple versions of the existing Jet database application in the same system. As long as you don't add SQL Server or MSDE to the database system, your existing system will still be a database system based on the jet/access solution. If you call a function defined in a previous version of Jet in one of your existing Jet database applications, or if you call a function that requires a lot of processing to convert the function to a SQL-compatible database, Using Jet as a database engine will be more advantageous than using MSDE or SQL Server 7.0.
Jet Summary
For those that are currently required to deal with a small amount of data, there are not many concurrent users to support, and in the future there will be no significant growth in the database management system, based on the Jet database system has low development costs, easy maintenance advantages, and with the previous version of the Jet database system has the greatest compatibility.
Under what circumstances should you choose
SQL Server
Looking at the title of this section, you might want to ask: Why not use MSDE or jet as the engine to develop all the database systems? The answer to this question is that the database system based on jet and even MSDE is in some cases unable to meet the actual needs. Below, we describe these situations.
The capacity of the database
A database based on MSDE can store up to 2GB of data size. Each file in a jet-based database can store no more than 2GB of data. Because Jet database files can increase storage capacity by linking to each other, the amount of data that is ultimately stored is limited by the size of the disk space. However, managing multiple data files will be a very difficult task. Therefore, if you have an existing database that is larger than 2GB, or will break through this limit in the future, choosing SQL Server as the engine for your database system will be the best choice.
Number of concurrent users supported
When the database system needs to support no more than 5 concurrent users, the engine with MSDE as the database will get the best system performance. Microsoft strongly recommends that the system support more than 5 concurrent users in order for the MSDE database system to perform superior performance.
From a technical and licensing point of view, the Jet based database system to support the number of users can reach 255, but in practice, the system supports the best number of users not more than 20. The reason for this is that the Jet database system uses a file-based approach to store data, so that as the number of connected users increases, so does the number of users who need to read and write to the file, resulting in poor system performance.
Because SQL Server can support thousands of concurrent users, it can meet the performance requirements of enterprise-class database systems to the greatest extent possible. Therefore, if a database application needs to support more than 5 users, choosing SQL Server would be the most sensible choice.
SQL Server Summary
If a user requires a separate database to process more than 2GB of data, and users require good performance when accessing the database system, SQL Server should be used as the engine for the database system. In all data engines, SQL Server delivers the most superior performance and the best scalability.
Explanation of MSDE License
Any user who has registered for Office 2000 Professional Edition or a learning version, or any user who has registered a tool component that is included in Visual Studio 6.0 Enterprise or Professional Edition, can get MSDE for free, including:
* Visual Studio 6.0, Professional Edition and Enterprise Edition
* Visual Basic 6.0, Professional Edition and Enterprise Edition
* Visual C + + (r) 6.0, Professional Edition and Enterprise Edition
* Visual InterDev (TM) 6.0 Professional Edition
* Visual J + + (r) 6.0, Professional Edition
* Visual FoxPro (r) 6.0 Professional Edition
License required to publish the MSDE solution
If Visual Studio 6.0 or Office 2000 developers use MSDE in the solution they create, they can publish their solution to their customers or end users as long as they adhere to the end-user License agreement for other software products that are used during the development process, Microsoft does not charge a corresponding royalty fee for developers who use MSDE.
Licensing required when an MSDE solution is interoperable with SQL Server
If a developer publishes an MSDE-based database application that needs to interact with SQL Server while it is running, they need to obtain a Microsoft Client Access License (CAL) for each copy of the database application that the developer installs on the client. For a central SQL Server database, developers also need to obtain a license for each copy of the installation. If you want more detailed information about SQL Server 7.0 quotes and licensing permissions, visit the relevant content in the SQL Server Web site:
Http://msdn.microsoft.com/isapi/gomscom.asp?Target=/sql/70/gen/pricing.htm..