Database server

Such systems can reside on the organization s intranet or over the Internet. Various types of hardware and software are needed to host a website. The hardware includes switches, gateways, and routers. Software includes, among others, application servers, database servers, web servers, authentication servers, and firewalls. On the other hand, the only hardware and software... 

Mainframes are large computers comprised of a cluster of tightly coupled machines or having multiple processors. These units will often be set up for specific applications as database servers, or for handling calculations such as those generated by quantum mechanics-based computational chemistry methods. 

The first form led to client-server-styled systems, with the client combining user-interface and application logic and communicating via SQL requests with a database server that dealt with persistence, transactions, security, and so on. All communication involved database processing requests in SQL, and clients did not communicate with one another (except indirectly through shared data on the server). 

A three-tiered architecture includes one more node between the client and the database server—the middle tier. In a three-tiered architecture, business logic is offloaded from the client and the database server nodes to the middle tier. In fact, you can choose to further distribute the business logic among more than one middle tier node and still call it a three-tiered (or K-tiered) architecture because the idea is similar. Note that the tiers do not have to be physically separated. You can have both the middle tier server and the database server collocated on the same physical computer but running in different processes with separate memory spaces. Modem hardware architecture can partition a single hardware box into multiple virtually separate computers or domains. Typically, a three-tiered architecture supports a Web-based thin client although it can also work with a rich client. 

By the same token, die database server can also be clustered, which is not illustrated in Figure 7.3. 

Another area of concern for the FDA relates to records sent over public networks, dial-up connections, or public phone lines, accessed through extemal/intemal web servers or by database servers. A number of security issues need to be considered in order to keep these records trustworthy. Intranets may face similar security issues if remote users connect to the central network resources through a local link to an Internet, even when password-protected access for the users is provided to just a small portion of a private network. These systems are considered by the agency as Open Systems (Part 11.30)4. For example, the Internet provides a convenient medium to connect to other networks, but it does not provide reliable security features, such as entity authentication, or protection from hostile users or software. 

Enterprise/Control Integration standard, ISA SP95.01. The plant management level is the plan repository area (e.g., database server(s)) that unifies production, quality control, inventory, and warehouse data. 

Correlation is usually co-located on the database server, because it also needs rapid access to all the tables in the database, and does not need to interact with the outside world. Performance is an issue because events need to be properly cleaned before they are presented to the operators. As such, correlation comes second after data acquisition for performance needs. It also needs read, write and update privileges on almost all areas of the database. 

Finally, presentation is also usually co-located on the database server, hosting also the web server. Access privileges vary according to the tables that need to be accessed by the users. Some users have only read privileges to access event data, while others will be able to modify event information manually. The performance requirements of the presentation function vary they need to be consistent with user needs, and thus directly depend on the capabilities of the hosting platform. 

Workstations. Workstations are the most powerful computers in the system, capable of performing functions not normally available in other units. A workstation acts both as an arbitrator unit to route internodal communications and as the database server. An operator interface is supported, and various peripheral devices are coordinated through the workstations. Computationally intensive tasks, such as real-time optimization or model predictive control, are implemented in a workstation. Operators supervise and control processes from these workstations. Operator stations may be connected directly to printers for alarm logging, printing reports, or process graphics. 

Search WWW for carbohydrate database servers. What information do these servers provide ... 

The last horizontal application to be discussed here is the database. Although most of the desktop applications include a database, another class of database software exists—the database server. The responsibility of this software is to manage all databases on a network in a central location. The application software on the user desktop can then access this database. Database servers are not used in and of themselves they are often the platforms on which other systems, particularly vertical market systems, are built. The advantage of using database servers is that the server generally resides on a powerful computer, giving users fast access to the data they need. Some of the most popular database servers on the market include Oracle , Microsoft SQL Server , and IBM DB2 . 

In this section we summarize the work undertaken by the Atomic and Molecular (A+M) Data Unit of the International Atomic Energy Agency. The A+M Unit has as its goal the establishment of databases of atomic, molecular, and plasma-material interaction data for support of fusion energy research. The Unit carries out a number of programs to fulfil this goal. These programs result in the establishment of databases which are put in electronic form and made accessible to the fusion community on a database server with connection to the Internet. 

The underlying atomic physics data, consisting of cross-sections for electron collision processes, radiative processes, and autoionization/di-electronic recombination will also soon be available. These complete sets of data are large and could not be accommodated by the existing database server. However, a new server is coming on-line and will be able to hold this extensive new database. In the future the entire sets of data for all five elements will be available through ftp retrieval. 

Henikoff, J. G., Henikoff, S. Pietrokovski, S. (1999). New features of the Blocks Database servers. Nucleic Acids Res 27,226-8. 

This is a statement that retrieves names (name) from a table of compounds in a database, restricting the results to those compounds that have a molecular weight (mol wt) less than 250, and presents the results in ascending order of the names. These statements do not include any algorithm or function that defines how the search is actually done the database server incorporates the business logic to do this. In addition, this is a declarative statement in the sense that it is more or less self-explanatory. 

Correct installation and conhguration of all systems of the supporting software environment — that is, the operating system, servers (e.g., application server, database server), and other components of a multitier system. 

The release of software is documented with a release certificate created by the QA team in cooperation with product management, which also creates the release notes for each product version. This document describes the enhancements and modifications finally implemenfed info fhe new product version. Prominent chapters of the release notes are — if applicable to the respective product version — new functions, modules, and configurations, changed functionality, functions that are no longer supported, as well as technical implications that require a change in the software environment (e.g., a new version of a database server). Release notes often include a list of known issues that have not been solved in the released version. 

Server-to-server for data transfer between different application servers or between database server and application server. 

The ReHAB databases for viral genes at www.virology.ca are maintained and updated by the VBRC, allowing this data to be accessed by the general public. In addition to the use described here, ReHAB can also be set up as a standalone application utilizing a user s own database server, and with a user s own query sequences, but it should be noted that the system requirements are... 

The BioMart data model is a simple modular schema composed of a central table, linked to its satellite tables by primary/foreign key relations. The schema can be normalized but typically includes denormalizations to achieve maximum query response optimizations. All the BioMart metadata is stored in XML configuration files on the database servers. The metadata files can be readily created and modified using MartEditor, a Java-based configuration editor. 

An introduction to SQL is provided in Chapter 3, but with an emphasis on examples relevant to chemical information rather than business information, which is often used in other books. Chapter 4 discusses some of the RDBMS that are available, namely Oracle, MySQL, and PostgreSQL. All of them use SQL to insert, delete, update, and select data. Chapter 5 shows ways in which client programs, including Web-based applications, are used to connect to the database server. Chapter 6 examines ways in which RDBMS are typically used to handle numerical and textual chemical information using relational tables. An example of using data files from the PubChem project is included. 

The RDBMS is installed and runs on a computer that functions as a database server. Any SQL commands are executed on the server by the RDBMS. Functions written in SQL or in any of the procedural languages mentioned above are also executed by the RDBMS. This has the advantage that the data tables used by these SQL commands or procedural functions are under the control of the server. This is the most efficient way to access the data. The disadvantage is that the server may have many requests to handle from many users. Another way to operate on data tables is indirectly, using a client program typically (although not necessarily) run from another computer. 

Because of the flexibility and familiarity of Web browsers, Web-based applications have become very popular and powerful. There are many Web-based interfaces to RDBMS. For example, phpPgAdmin1 is a popular Web application for PostgreSQL. PhpMyAdmin2 is popular with users of MySQL. These applications allow one to connect to a chosen database server, browse the schemas and tables in the database, and enter SQL commands. The output from SQL commands, especially table output, is formatted nicely. Other operations, such as creating, altering, or dropping tables and schemas, are also provided. These use an HTML form interface, with text boxes, radio buttons, check boxes, and other form elements familiar to all uses of the Web. 

One advantage of Web-based applications is that the Web browser can be run on virtually any desktop or laptop computer. The database server itself can be located elsewhere, use a different operating system, and be maintained by others. In addition, the Web server can reside on yet a third... 

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