Client Applications

Other client applications are also available for use with an RDBMS. Compared to Web-based applications, client applications are more specific to the particular client desktop or laptop computer. For example, PgAdmin3 is used to interact with PostgreSQL. Various versions of 

PgAdmin are available to be run on Linux, Windows, Mac, and other clients. Oracle users typically use Oracle s SQL Developer or Toad (Toad also works with MySQL). SQL Developer4 is a Java application that uses JDBC to mediate the communication to the database. A typical user need not be concerned with this, but a later chapter of this book discusses ways to construct new client applications using JDBC, ODBC, and other methods to communicate with the RDBMS. Toad is a Windows only application with a free version and a full-featured pay version.5 

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Another useful client program is R.6 It is used for statistical analysis of data and has some nice graphical capabilities as well. There is an add-on to R that uses ODBC to communicate with an RDBMS server.7 Consider the following R program. 

Many other useful client programs allow input of data using SQL. For example Spotfire8 and Pipeline Pilot9 allow data to be read for an RDBMS using ODBC. 

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Client Applications A client may be used for more than one application (e.g., MRP II, LIMS, and EMS). Each application will have an associated file set providing what is often referred to as its Graphical User Interface (GUI). File sets are usually built into standard client set-ups. Individual files may include some element of configuration. GAMP level 3 (e.g., Windows NT) and GAMP level 4 software require the version to be recorded, operability confirmed, and any configuration validated. Supplier Audit requirements are usually satisfied as part of the server application validation. 

J3 Are processes in place to management to deployment of client applications ... 

Special emphasis has to be placed on interfacing electronic data management system with expert systems, specific client applications, or other data management systems. The focus lies on open and standardized communication technology. 

Client-to-client for client applications to share data in a standardized way. 

If an agent transferred data to an application server, the client software requires some functionality to view and use these data. One solution is the concept of a generic inbox. Similar to an e-mail inbox, this feature allows receiving converted files sent from a software agent in the client application. 

When developing a client application, one or more computer languages will be chosen. The purpose of this section is not to advocate one language... 

This chapter discusses ways in which more complex client applications can be written. These programs use SQL to select, insert, delete, or update tables in the database. Depending on the computer language used for the client program, a variety of interface libraries is available. 

Do not implement the same functionality in different clients. If many different clients require the same functionality, it is better to encapsulate that in one central location—namely the RDBMS. For example, if it is necessary to compute molecular weight, it is better to have a server-side function do this in a consistent way rather than to implement such a function in each of the languages used for client applications. This may be more obvious for functions like fingerprints that are more difficult to re-implement in various languages. Moreover, it is essential that fingerprints be... 

Only transfer data the user needs to see. There is always a need to transfer some data to and from the server. When a user enters data from a file or other source, it must be transferred to the database server in order to be inserted into the database. Similarly, when a user needs to see data values or a structural depiction, it must be transferred to the client application. However, if the data only needs to be processed by the client and then transferred back to the server, be sure to transfer only required columns. Also consider again writing a server function to process the data as required. 

There are other advantages to importing structural data into the RDBMS as soon as possible. Depending on what other tables are in the RDBMS, it will now be easy to discover which structures are already contained in other tables of the RDBMS. The data in the new table will be easily accessible to other users and client applications. Once a decision has been made about which new structures are of interest, these can be readily moved to other tables in the RDBMS for further work (purchasing, testing, synthesis, etc.). 

There are many uses for a chemical relational database. Some of these have been mentioned in earlier chapters. In this chapter, three general types of applications will be discussed. The purpose is not to present complete working applications, but to indicate important issues to consider when designing such applications. Sample schemas are proposed. The use within each application of the core functions described earlier is discussed. Each of these applications might be developed as a Web application or a client application on a user s desktop. Any computer language might be used, although the ability to connect to an RDBMS is essential. 

From the users point of view, the system is transparent - the agent takes the snapshots and presses the button OK, then puts the mobile device in his/her pocket and waits for the feedback. In fact, the client application manages the data transmission imtil receiving the acknowledgement. An HTTPConnection instance will be used for opening a connection to the PHP upload component and sends the data packets. 

The web application - is a web-client application that has/ gives/ allows access to the data stored in the Datacenter. It can be used by researchers, students and PhD students to study different cases classified by the Datacenter. The access is controlled by the data center administrator, who is entitled to issue access accounts based on username/password pairs. 

An example of both a flow specification and a flow implementation is given in Figures 2 and 4. The excerpts are taken from the electron microscope s motion-subsystem that is responsible for moving the specimen holder. The system consists of three major components working in a dient-server environment the motion dient, the motion server and the motion controller. The motion server receives its stage movement commands from a client application, processes it and moves the motion controller to the desired position. The externally visible flow of the move command is shown in Figure 3, which corresponds with the textual AADL representation in Figure 2. 

The flow starts with a move request from the client application and ends with the server. Internally, the server simply places the command in a queue, therefore this flow ends here. A part of the AADL textual representation given in Figure 2 specifies this behaviour of the flow. 

STATPack mobile was designed to be a thin-client application and when appropriate the existing code was used. By using the existing server code as much as possible, the development time was minimized and process consistency between the two systems was preserved. By extending the server code to the mobile platform, fhe developmenf feam was able to optimize their time and avoid introduction of new bugs or errors thaf would have required additional resources and time to fix. The functionalify for the STATPack mobile system was prioritized based on the previous information from the requirements ... 

The image was derived from IP Axis cameras whose main characteristics are given in Table 3. The server performs additional video compression using bilinear interpolation based on the designated bandwidth. Throughput restriction is performed by the client application. It reduces the bandwidth of the client interface to the value declared in the application window. The measurement results are related to quality indicators defined in the following recommendations (ITU-T G.lOlO Recommendation, 2001), (ITU-T P.800 Recommendation, 1996). 

Figure 8. Image quality shown in client application window (a—EF class of services selected for video stream, b—BE class of services selected for video stream).

However, network performance still presents an obstacle because each stack must be sent from the client application to a server before remote processing transport time is therefore non-negligible. The extent to which speed is in-... 

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