Server software must provide access to a variety of data sources and not be restricted to vendor-supplied sources. This connectivity is in part due to vendors "opening" up access to their data structures via application program interfaces.
Data gateways provide access to external databases. Most database gateways use structured query language as the access language. With a simple pass-through database gateway have software on both the sending and receiving nodes.
This allows the software to optimize the query and supports portability but does not allow the use of any special features that might be in the structured query language of the target database. Microsoft's Open Database Connectivity (ODBC) application program interface permits applications to communicated with relational and now-relational data sources. Open Database Connectivity, compared to proprietary database management system.
It is based on the call-level interface developed by the structured query language access group. Open database connectivity drivers allow developers to write windows-based applications that transparently access the data sources supported by the drivers. Announced open database connectivity drivers include links to structured query language server from information builders, Incorporated.
Remote Procedure calls:
Designing client/server applications is fundamentally different then building traditional mainframe or macro-based micro applications. Programmers should be isolated from network intricacies and given easy access to network functions. Remote procedure calls and message queuing systems provide this service.
Remote procedure calls are currently more widely used than message queuing systems. Remote procedure calls, which are application program interfaces layered on top of a network inter-process communication mechanism, allow servers to communicate directly with each other.
They allow individual processing components systems; system management, security, and application programming depend on the capabilities of the underlying remote procedure call mechanisms. Server access control and the use of a directory service are common needs that can be met with remote calls.
Remote procedure calls also manage the network interface and handle security and directory services. The paradigm of using high-level languages to call procedures is not new. A remote procedure call should look and act just likes a local procedure call to the programmer. The idea is to spread work and data over the network to optimize resources.
Remote procedure call tools usually include:
1. A language and a compiler that can be used to produce portable source code.
2. A run-time facility that makes the system architecture and network protocols transparent to the application procedures.
1. A language and a compiler that can be used to produce portable source code.
2. A run-time facility that makes the system architecture and network protocols transparent to the application procedures.
Sun soft's general-purpose Transport-Independent Remote Procedure call toolkit is based on source-code generation technology from Net wise incorporated. The software allows software developers to create a single version of a client/server application that will run unmodified across a range of operating systems, hardware bases and networks such as TCP/IP, OSI Net Ware's IPX.
It has one major limitation. They typically require synchronous connections. If an application uses a procedure call to link to a server that is inoperable or busy, the application will wait for the data rather than moving to other tasks.
I am Dharu, I completed BE in Namakkal. Now, I am working Adsysindia from Bangalore.
Article Source: http://EzineArticles.com/?expert=Dharu_S_Shanthi
Article Source: http://EzineArticles.com/6393647
No comments:
Post a Comment