Windows DNA 3 data access logic

Network application systems are inseparable from data, and data carriers can be DBMS and XML files. In terms of architecture, the objective of Windows DNA is separation, which includes the separation of data access logic. Therefore, Microsoft provides a unified data access component for developers to develop Windows DNA applications. The most important technologies are ado, CDO, and ADSI. ADO is used to access database data. CDO is used to access data existing in exchang server, and ADSI is used to access data existing in Windows Directory Service.

There have been many database data access logic components in history, some of which are still in use and some are discarded. Such as Dao, rdo, ODBC, and ole db. As an encapsulation technology of ole db, ADO shields the differences between different underlying data sources and tries to achieve unified data access. To achieve unified data access is conditional, it is some Framework guidance proposed by Windows DNA. Windows DNA believes that simple data access such as crud operations should be implemented in the form of stored procedures, while business logic should be processed by business logic components, which is conducive to system scalability, in addition, you can achieve unified data access to a certain extent, and reduce the traffic to access the data source. I am not going to introduce ado, because there are many books for reference, such as ADO. net, ADO. Net advanced programming, and so on. In general, the logic implemented by ADO is to convert the executed SQL statements and stored procedures into dialects of a specific database, and pass the statements to the database server for execution through socket.

CDO is used to access data in Exchange Server. Because many application systems are integrated with Exchange Server, developers need a simple way to access data in Exchange Server, in this way, the application system and Exchange Server can be integrated at the data layer. CDO is a good way. I am talking about the Windows DNA era .. Net era has developed to the present exchange server 2010, and Web Service has become a better way and Microsoft prefers it.

ADSI is used to access data stored in the Windows directory server. Objects stored in the Active Directory can be divided into three types: user information, application system information, and enterprise information. Unlike relational databases, the data stored on the directory server is not relational but hierarchical. Therefore, the Directory Server is more suitable for storing "80 read 20 write" data, while the database server is suitable for storing "50 read 50 write" data. ADSI is a programming structure for accessing directory services. It provides a simple, powerful, and object-oriented excuse for active directories and other directory services.