Microsoft Data Engine MSDE
Overview Developers who create applications face this option: Which technology should you choose in numerous database options? Developers need to consider many factors before choosing a database technology. For example, how many users do you need to support? Does all users visited the database system at the same time? What is the cost of the application? If the demand for the application changes over time, is this technology to expand the function and size of the database? Until recently, Microsoft launched two database management scenarios: Microsoft Jet (ie Microsoft Access Data Engine, which releases Access and Microsoft Visual Studio) and Microsoft SQL Server. Since each technical solution has its own advantage, there is some limitations, so before, if the developer is required to choose such a database technology: make it only to run from the desktop to the data center environment, and the database application The procedure is adapted to long-term and short-term needs, which is generally difficult. Since Jet-based solutions have an advantage that is easy to use and developed, it is a very good choice for desktop or shared applications. However, developers have discovered that with the expansion of the application system, the program code needs a lot of modifications to the program code before they transplanted the Jet application to the SQL Server platform. It is worthy of developers to be happy with: With a release of the SQL Server Compatible Data Engine (MSDE), developers can use a new way to create a desktop and shared database applications. With MSDE, developers can create a free distributed desktop and shared database solutions. Database applications using this solution can be easily ported to SQL Server when expanding the size of the system. What technologies involved in nature, a "data engine" in operation is a core process. A database management system, such as Access or SQL Server, will use this core process to store and manage data in the database. In this sense, we can usually see a data engine as a database management system without a corresponding graphics management tool. There are two main functions of the data engine: one is used to store data, and the other is used to process the request submitted by other objects to store information. We usually refer to the request to retrieve or update the data as a database query. Typically, the data engine responds to a database request submitted by the client application with a custom database application. Custom database applications are created with some development tool, such as Microsoft Visual Studio. In this case, since the custom database application already contains a built-in tool to manage the underlying database, in the data engine, there is no need to include the graphics tool to manage the database. Further, since the data engine has an easy distribution, the developer can include the corresponding data engine to a custom application. During the installation of the application, the user can install it into the system by selecting the engine component. The Microsoft Data Engine Microsoft Data Engine (MSDE) is fully compatible with SQL Server, in the desktop and shared database solutions created by Visual Studio 6.0 or Access 2000 for the development tool, the engine can be used to process the database. For Visual Studio 6.0 or Access 2000 developers, they can publish database applications created using MSDE without registering MSDE alone.
MSDE uses some technologies provided by SQL Server and is fully compatible with SQL Server 7.0. In Access 2000, MSDE is ideal for instead of Jet (the default engine used by the Access 2000 database). In addition, for Visual Studio 6.0 developers, if they want to create custom database applications, and want to use the database compatible with SQL in these custom applications, they can use MSDE as a data engine. The way is to achieve this. The compatibility of MSDE and SQL means that developers can transplant them into SQL Server for existing MSDE as data engines, desktops, and shared database application code. MSDE is running in the background in a way to provide some service. Here, the service refers to an application that runs in an after-standing process. The service method of the service is different from other applications. For example, as long as the user selects the "Start" option from the Start menu, the corresponding application can be put into operation. But for the service, such as MSDE, the situation is not the case. Their startup and closing is usually done by the operating system. The MSDE is used as a desktop and shared database applications that usually have the following restrictions: During the database application survival, the MSDE service should be in operation. In general, the use of services is other applications, not end users. In general, the service runs in the background, when it receives the client application to process the process request, it turns to the corresponding request. For MSDE, these requests are some operations that will be performed on the database. Since the object of the service is a client application, not a terminal user, the service does not need to have a user interface. One project created in Access 2000 or a Visual Basic application can interact directly with a service. For MSDE, these client applications act as user interfaces. MSDE features: * is completely compatible with Microsoft SQL Server 7.0 and previous versions. * For Visual Studio 6.0 or Microsoft Office 2000 developers, they can publish MSDE-based database applications to end users. * You can run on Windows 95, Windows 98, Windows NT, and Windows 2000 (Intel, and Alpha) platforms. * The architecture with the client / server (MSDE is in the database server, not the operation of the database on the client). * Run in the background by providing services. * During the development of the database, developers do not need to create the corresponding user interface for the engine. Other applications, such as custom applications developed with Access 2000 or Visual Basic, need to provide the database to the database. Jet 4.0Jet 4.0 is the default data engine used in Microsoft Access 2000. This engine is also included in the Visual Studio 6.0 development kit. Jet is a file-based database management system. This type of database management system has the following characteristics: The database in the system is included in a separate database file, and the read and write operations for the database are controlled by the client. JET can be used in a multi-user environment, and developers can also expand the database application using Jet as the engine as a desktop and shared database application. Microsoft Access provides an easy-to-use interface for Jet data engines. Developers can also use Visual Basic or other development tools to create custom front-end applications, in which applications contain the database as the engine.
SQL Serversql Server is a database management system based on client / server mode. Unlike the engine used in file-based databases, in a client / server-based database management system, the data engine will be responsible for managing the read and write operations of the database. Due to this feature, based on the database management system based on client / server mode, such as SQL Server, the number of concurrent users and data can be processed in a large extent can be improved. Currently, large database applications used in the enterprise require support for concurrent users and data volumes, and SQL Server is designed to meet this urgent need. These database applications include enterprise management systems and decision support systems that have been implemented today and further improved in the future. SQL Server has a variety of distribution to meet the data volume, concurrent users of the processing in different environments, the number of users and the hardware. The compatibility database of the database and SQL is compatible with SQL. Both MSDE and SQL Server comply with language specification defined in Transact-SQL (T-SQL), and Jet does not use this specification. Unlike this, JET defines and implements its own set of query languages. In this query language, JET can call the function procedure in the Visual Basic Application (VBA). Transact-SQL is a set of well-defined languages that can communicate between database applications and database servers through this language, and can program processing for database servers. Transact-SQL is a supercoming ANSI-SQL, using Transact-SQL, developers can make some custom transaction logic processing by programming the server by programming the server. The user can actually execute by the transaction logic processing process driven by the client or message, while actually executed, is done on the server. MSDE is consistent with Transact-SQL language specification means that objects in MSDE are not modified to run in SQL Server. Therefore, at this point, MSDE is superior to Jet. How to choose a data engine If your hand's database application features and size can no longer meet the needs of the database system, you may have to create a new application-based application-based application, or you may intend to replace it by using a new data engine. The original engine manner is transplanted for existing database applications, regardless of the way you use, a certain understanding of the characteristics of each data engine that is scheduled to use, is very important. So, what kind of data engine should you choose? If you want to create a desktop and shared database app, then you can consider using MSDE instead of Jet. In this section, we discussed the needs of many database applications on the system, in addition, we also provide some suggestions to tell developers how to choose a suitable data engine so that the engine can be in the largest The degree is met to meet the project needs they will create. Database applications Table 1 lists the needs of database applications running in an enterprise environment and indicates how much each data engine can meet these needs. If your application has any requirements given in the leftmost column of Table 1 in the future, you should consider using MSDE instead of JET as the database. In any case where MSDE should be selected as the engine of the database system in the following two cases, we can use MSDE as the engine of the database application. First, use MSDE instead of Jet to port existing database applications to increase its scalability.
The second is to create a desktop and shared database application as an engine. When the size of the system expands, these databases can be easily ported to SQL Server. MSDE compatibility with SQL Server MSDE data engine is fully compatible with SQL Server. Therefore, the table, stored procedure, trigger, and other database objects created in MSDE can run in the SQL Server database without any modification. However, objects created in the JET, such as query objects, cannot be running to the SQL Server database without any modifications. If you want to transplant the currently created database application into SQL Server, or existing database applications are handled in the process of concurrent users, the amount of data or other aspects have or will exceed the limit of the JET engine, then, The MSDE should be selected as the data engine of the application. With this solution, you can transfer your database applications to SQL Server without modifying any code. Based on the server's processing and JET, MSDE is not a file-based data engine, so the database application of MSDE as the engine will not be restricted by the amount of data based on file-based database. Due to the file-based database, the operation of the database is performed on the client, so this type of database affects the performance of the application. In the server-based database system, such as in SQL Server and MSDE, the operation used to process the client application submitted is done on the server. After the request is processed, the server will result Returns the client application to the submit request. This treatment is used to greatly reduce the load of the network, and it can also enable the user to access the database at a speed that can be accepted without a higher configuration terminal. When multiple users use a file-based database while using a file-based database, each user must open the same file to read the information from the middle. Since each user is only in his order to perform a corresponding operation on the database file, the file-based database will become a bottleneck affecting system performance. The server-based database management system is specifically designed to resolve this problem encountered when the client application accesss the database management system, so it can improve the performance of the system. When the client application is distributed on the network, the client processing data will further reduce the performance of the file-based database system. When a file-based shared database is placed on a file server in the network, if the client application submits a query request to the file server to perform the corresponding operation on the shared database, only one record is generated even if the result is performed. The file server also needs to pass all source data contained in the request via the network to the client application of the submitted request. In a server-based database, the data engine will perform all the processing requests submitted by the client application on the server. After the processing is complete, only the result is returned to the client. In this mode, the application is still able to access the database on the server with a narrower network connection in a narrow bandwidth. If your database application is distributed on the network, multiple users need to access your database at the same time, or users can only access network connections narrower through a bandwidth, as long as there is any case, you should use MSDE As the engine of your database application. Safety Although both MSDE and JET allow for the table or stored procedures to make the necessary protection, the MSDE database running on the Windows NT or Windows 2000 platform can protect the database object with the security mechanism provided by Windows 2000, but Jet databases do not have this feature. If you want to take advantage of this security mechanism provided in Windows 2000 in the database application, you should choose MSDE as your data engine.
Customers who are authorized to register for Office 2000 or Learning version, or any registered users who have access to the tool components included in the Visual Studio 6.0 or a professional version can get MSDE for free, including: * Visual Studio 6.0, Professional 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 For developers who use MSDE as a data engine to create a desktop and shared database solution, as long as they register the software below, they can be authorized for free to publish them to create MSDE solutions. These software products that need to register include: * Microsoft Office 2000 Development Edition * Microsoft Visual Studio 6.0 Professional or Enterprise Edition Related Tools Components (These tool components are listed in this section) For those Microsoft Office or Visual Studio As developers of development tools, if they contain a database of Jet as an engine in the app, they are also authorized to release these databases for free. However, it is not convenient to port as the desktop and shared database applications in Jet as the engine. If the development cost is an important factor that affects the creation of a database application, the engine of MSDE as a database is your best choice. MSDE Summary If the developer wants to create a desktop or shared database application, and plan to expand these database applications in the future, selecting MSDE as a data engine will have the following advantages: from the near future, it can reduce The development cost of the system, from the long run, but also provides the most convenient way to transplant the currently created database application. When your organization's scale is expanded, you can make new demands for the function and performance of the database system, you can completely transplant it to the SQL Server-based platform without modifying any code in the existing database application. run. In addition, since MSDE is fully compatible with SQL, developers can use the same data access language to seamlessly convert between large-scale MSDE database systems and larger SQL Server database systems. In which case Jet is selected for some special database systems, it is also a very good choice as an engine as a jet 4.0. In this section, we will discuss what circumstances should be used as the database engine. Distributed In a database system using JET as the engine, since the database is included in a separate file, the work of backup and publishing the database is very easy. Although other files accesses the Jet database files through the type of application such as Visual Basic or Microsoft Access, but because developers have a good definition of the correlation between these files, The operation of accessing the database file does not take up a lot of storage space or use a large number of processor resources. MSDE database is more difficult to publish and install compared to Jet databases. Therefore, if you want to simplify the process of publishing and installing the database, the engine selecting JET as a database is a very good choice.
Development cost developers can release the database applications based on JET 4.0-based databases with the following tools: * Microsoft Office 2000 * Microsoft Access 2000 * Visual Studio 6.0 Related tool components in any version (in front of the article These components) If the development cost is an important factor to consider when creating a database application, selecting JET as a data engine is a very good choice. Both scalability MSDE and Jet databases can run in desktops and shared database applications. For some database applications, the amount of data they handle will never exceed 2GB, and the number of users support will not exceed 20. If you have a Jet database application, even with the size of the system grows, the amount of data it is not very large, and the number of users who need to support is not enough, then Jet is the engine of the existing database. Still a good choice. Demand for system resources Since the Jet database has undergone compression processing, it is appropriate to select the JET as a database in terms of limited resources. In the three data engines discussed in this article, the stored space and consumption of the storage space and consumed system memory are least in the database. If the machine's disk space or system memory is very limited, then the JET will be very sensible. With previous versions of compatibility Jet 4.0 provides maximum compatibility for databases based on previous versions. You can run existing multiple different versions of Jet database applications to run in the same system. As long as you don't join SQL Server or MSDE in the database system, your existing system will still be a database system based on Jet / Access solution. If you call a function defined in the JET version in your existing Jet database application, or call such a function: you need to make a lot of processing to convert the function into the SQL-compatible database. Operation, then the engine using JET as a database will have greater superiority than using MSDE or SQL Server 7.0. JET Summary is not much data in the current requirements, and the number of concurrent users that need to be supported is not much, and in the future, there will be a large growth database management system, and JET-based database systems have development fees. The advantage of low, easy to maintain, and has the greatest compatibility with the previous version of the Jet database system. In what circumstances, SQL Server should choose to see the title of this section, you may want to ask: Why don't you develop all database systems as an MSDE or JET as an engine? The answer to this question is that JET or even MSDE database systems can no longer meet the actual needs. In the following, we have explained these situations. The capacity of the database is based on MSDE-based databases to store up to 2GB of data. The data that can be stored in the JET-based database cannot exceed 2GB. Since the Jet database file can increase storage capacity by mutual linking, the final storage amount is limited only by the size of the disk space. However, managing multiple data files will be a very difficult job. Therefore, if your existing database has more than 2GB, or in the future, it will break through this limit, then the engine selected as a database system will be the best choice. Supported concurrent users When the database system needs to support the number of concurrent users, the engine that uses MSDE as the database will achieve optimal system performance. Microsoft Tropic: In order to make MSDE database systems exhibit superior performance, the number of concurrent users supported by the system should not exceed 5. From a technical and authorization point of view, the number of users supported by JET-based database systems can reach 255, but in practice, the number of users supported by the system should not exceed 20.
