discusses the three system architectures for a distributed database system (client/server, peer-to-peer and MD
550473
To have a distributed database system, first, you need to make sure that each individual database has the same structure and layout as all the others, ie the same columns, type, etc.  \n\nSecond, you need to make sure that no data is duplicated from one pc's database to the next.\n\nFinally, if both the first and second criteria are met, and all database tables are in 3rd normal form, I would use a client/server system, and each PC would be just a client, rather than trying to tie all PC's together as a though they were one massive server.
32674
A standard form of communication between multiple objects.
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I understand you want to implement something like Peer to Peer file sharing but, instead backups.\nThis is not efficient because first of all backups are large and they cannot be easily transferred, also there would be huge netwrok traffic.\nThey must kept safe and secure.\nThe transmission is not safe, as your application may open a port on each computer.\nYou would have firewall issue.\nThere are FTP services for such a purpose.\nBut I can give you a better Idea.\nTo setup a central Virtual Backup Server.\nThis is a virtual Private Netwrok that has a storage and allocates storage for each user, The server should use FTP, or TCP (HTTP like file manager), and the server should kept safe.\nI would suggest use Hosting from data centres, Like Brinkster.com.\nthe setup is easy and you may not need any other applications to build.\nHowever you should be aware of your bandwitdh limit.\n;) good Luck\nMrB
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Data base management system by F.Korte.
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I would start with the Db design. You are going to need a junction table to resolve the many to many relationships you are going to have. \n\nSo if your user table has fields like\n\nUserId\nName\netc..\n\nThen your second table will need sometihng like\n\nFriendID\nUserID1\nUserID2\n\nThen you will be able to resolve the names of the people who know one another and draw your relationship. When you add the link, then a record will need to be inserted to keep track of it for future requests. \n\nYou are going to need a lot more than this, but this should get you a start. I would look at using something like DotNetNuke to take care of some of the plumbing of the application and then just write  a module for DNN then will allow you to accomplish your logic here.
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You would need Apache server http://httpd.apache.org/, you might also want to install MySQL http://www.mysql.com/ or PostgreSQL http://www.postgresql.org/ for database management.  In addition you might also want to install PHP www.php.net to run PHP scripts. With those 3 things you should be able to start a simple web server.
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As stated, all of these technologies would be usable by you for free.  The java core technologies are free to use (as are a number of middle-tier / application servers you may need) and since you wouln't be redistributing any mysql components (or embedding it in anyway) I believe it would be cost-free for you to use as well.  \n\nAs for servers I currently use both 1&1 and Rackspace (though not cheap) with more than adequate results.
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Wireless networks are generally used by clients to access network resources.  Servers usually need far more bandwidth than wireless can provide and get connected to the network on dedicated ethernet ports.  \n\nDistributed database systems, again, run on servers.  Unless there is some incredible leap in wireless technology, servers aren't going to be on wireless networks.  The clients may access the servers over a wireless network to the traditional network, but the servers aren't ever going to be placed on wireless NICs.  \n\nSo the answer to your question is that wireless networks really don't have any effect on the use of distributed database systems other than possibly being able to serve more clients.  \n\nIf you want sources to cite for this, go to www.cisco.com and look for infrastructure planning information.
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There are basically a few things that can be considered CRUCIAL: the cost, the application requirement, and the performance. I think it boils down to what is the highest priority to you. For my case, the highest is the cost, then the business requirement, then the performance.\n\nOnce you get yuor priority sort out, the rest is simple. Do you know what is the best combination (DBMS + Web_server + front_end_tools) in terms of cost/performance? In my humble opinion I would say MySQL + Apache + PHP. Why? See, I can have SQL+Apache+PHP installed in my WinXppro workstation as single-user environment for development. Then I can deploy the app in either Linux or Windows which has the 3 installed. It can be deployed in a client-server, intranet, or internet environment regardless of OSes. The best is, they are free.\n\nAnd all the client computers need are a web-browser.\n\nFYI, you can obtain ODBC for MySQL if you are to use Access instead of PHP+web_browser as the frontend.\n\nHow about OS?  I think it's entirely on you. All you need to think about is who's going to install/configure/maintain the system and how much does it cost you short & long terms. As for me, I go for Linux because: \n1) it's free, and it comes with MySQL, Apache and PHP;\n2) it's not as hard to install as you would think, and there are tutorials all over the web;\n3) without spending too much (on Windows+CALs) usually makes my top manager happier;\n\nHope this help.
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J2EE is helpful in developing multitire enterprise application. you can go through this link also
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datamining\nnetworking\ndatabasing
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No. The Internet is not a database (as the term is used in common usage) because although it stores information like a database, and can be used to access that data, it is a larger entity having many more characteristics.  The Internet is a network of computers (nodes) that can be used as a vehicle to serve up files located on one or more computers at one or more IP addresses or URIs (see sources)(which themselves can be databases).\n\nA distributed database is a set of tables organized into a file or multiple files that contain rows or "records".  The database application can access these files and rebuild the database, or query the appropriate tables for the necessary records and process them to satisfy a user query.  If the database is "distributed" then the files are stored on multiple computers at one or possibly several IP addresses.  The term distributed just means that the files are stored at different locations (computers).\n\nThis is a great question and thought provoking because databases as we know them (or knew them) have acquired a larger scope and become defined by their ability to be distributed.\n\nMaybe the term database needs to be redefined???\n\nCool.  I don't think there is any right or wrong answer, it just depends on how loosely you use your terms.
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The problem your going to find is pulling the database thru any VPN. The size of your pipe vs. the size of the database will limit how useable the process actually is. If your actually opening, writting and saving you'll find it an impossible task if the database is of any size.\n\nThe best solution for this is Terminal Server and VPN. You host the database on a central Term Server then remote users VPN in and run the database locally and only the screens are moving back and forth instead of the data itself.\n\nThere are otehr solutiosn such as Sharepoint and Foldershare but as I said the size of the database is key.\n\nFeel free to contact us for more info.
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Back in the eighties when network equipment vendors first started to hawk their wares, the term client/server was used to conjure up a host of fancy capabilities offered by the new hardware. Today, client/server has a very specific meaning that has nothing to do with hardware at all. Even so, most folks still associate the term client with the physical computers they are using and the term server with some other physical computer to which they are connected. There's a glimmer of truth there, to be sure, but today client/server means much more.\n\nWe're going to cover the essentials of client/server computing. We'll define one-tier, two-tier, three-tier, and n-tier client/server program architectures; we'll explain the difference between a thin client and a fat client; and we'll discuss the middleware concept. But first, you need to understand a few things about general software architecture.\n\nMost application programs have three major layers. On top is the presentation layer, which provides the human/machine interaction (the user interface). The presentation layer handles input from the keyboard, mouse, or other device and output in the form of screen displays. In the middle is the application or business logic, the functionality that gives the application program its character. Application logic makes the difference between an order entry system and an inventory control system, for example; it is often called business logic because it contains the business rules that drive a given enterprise. The bottom layer provides the generalized services needed by the other layers, including such things as file services, print services, communications services, and, perhaps most important, database services.\n\nFor simplicity, we will confine this discussion just to those programs needing database services. That's what most architects first think of when they hear the term client/server, but the general rules apply to any kind of service.\n\nThe number of tiers in a client/server application is determined by how tightly or loosely the three program layers are integrated. A one-tier application is one in which the three program layers are tightly connected. In particular, the presentation layer has intimate and detailed knowledge of the database structure. The application layer is often interwoven with both the presentation layer and the services layer. All three layers, including the database engine, almost always run on the same computer.\n\nOne-tier applications are easy to design and write, especially with today's modern software tools. It's also possible to create a multiuser one-tier application by running the application on several PCs and having them share the database. The database can be stored either on one of the PCs (a peer solution) or on a file server. Note that each PC running the application has its own copy of the database engine; only the data is shared, not the database logic itself.\n\nMultiuser one-tier applications are okay until the number of users gets large. The problem is that all the database work is performed in each client. For example, if the program needs to list all clients with the last name of Smith, all the information (indexes and data records) needed to resolve that query to the database must be transferred over the network. For some complex queries, a significant amount of data must be examined, perhaps even the entire database. At a more technical level, it is difficult to manage independent database engines to be sure that no conflict arises when two clients attempt to access or update the same record. This is called the record-locking problem.\n\nThe solution for the performance and technical problems associated with multiuser one-tier programs is two-tier client/server architecture. This type of application is written in mostly the same way as a one-tier application, with the exception that the database service (engine) no longer runs with the client. Instead, it
19999
The Universal Enterprise Infrastructure ("the infra") is an online database application system that conforms to standards promulgated by Neutral Third Party ("N3P"). The infra is a service that operates over the Internet.\n\n\nDescription\nThe Universal Enterprise Infrastructure ("the infra") is an organized body of related information similar in design to any privately-owned database application. Unlike an organization's private database software, however, business procedures and data stored on the infra can be shared by multiple organizations and consumers via the Internet.\n\nIn an organization's internal database application data can only be related—and procedures applied—to the information the database contains, or to other database applications with which it is compatible. The organization must employ custom software or web services to relate the application to incompatible database software. On the infra, business procedures and data are stored in a distributed, central repository by many owners—organizations and individuals. These owners retain separate, iron-clad control over their information, enjoying a level of security and privacy that meets or exceeds the level found in today's well-run organizations. Standardization lets developers easily relate data and apply procedures of one organization or individual to another, providing seamless interactivity among participating database applications.\n\nDevelopers create infra applications in much the same way as standalone database programs except that, to avoid redundancy, individual procedures are stored in reusable templates and data replications are avoided. This approach lets developers assemble commonly-used data and procedures to create an unlimited variety of innovative applications.\n\nA product of collaboration in a neutral environment, the infra is based on readily-available technologies and well-known principles. Members of the N3P ([1]) community contribute data and business procedures common to every industry and country, store them in a distributed database, and make them available to any device or computer connected to the Internet. Organizations use these shared, online components to achieve interoperability among existing database applications—-regardless of ownership, location, make, version or design. The infra also enables database applications to be designed expressly for delivery via the Internet.
381998
A peer-to-peer (or P2P) computer network is a network that relies primarily on the computing power and bandwidth of the participants in the network rather than concentrating it in a relatively low number of servers. P2P networks are typically used for connecting nodes via largely ad hoc connections. Such networks are useful for many purposes. Sharing content files (see file sharing) containing audio, video, data or anything in digital format is very common, and realtime data, such as telephony traffic, is also passed using P2P technology.\n\nA pure peer-to-peer network does not have the notion of clients or servers, but only equal peer nodes that simultaneously function as both "clients" and "servers" to the other nodes on the network. This model of network arrangement differs from the client-server model where communication is usually to and from a central server. A typical example for a non peer-to-peer file transfer is an FTP server where the client and server programs are quite distinct, and the clients initiate the download/uploads and the servers react to and satisfy these requests.\n\nSome networks and channels, such as Napster, OpenNAP, or IRC @find, use a client-server structure for some tasks (e.g., searching) and a peer-to-peer structure for others. Networks such as Gnutella or Freenet use a peer-to-peer structure for all purposes, and are sometimes referred to as true peer-to-peer networks, although Gnutella is greatly facilitated by directory servers that inform peers of the network addresses of other peers.\n\nPeer-to-peer architecture embodies one of the key technical concepts of the internet, described in the first internet Request for Comments, "RFC 1, Host Software" [1] dated 7 April 1969. More recently, the concept has achieved recognition in the general public in the context of the absence of central indexing servers in architectures used for exchanging multimedia files.\n\nThe concept of peer to peer is increasingly evolving to an expanded usage as the relational dynamic active in distributed networks, i.e. not just computer to computer, but human to human. Yochai Benkler has developed the notion of commons-based peer production to denote collaborative projects such as free software. Associated with peer production are the concept of peer governance (referring to the manner in which peer production projects are managed) and peer property (referring to the new type of licenses which recognize individual authorship but not exclusive property rights, such as the GNU General Public License and the Creative Commons License).
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Generally a three tiered architecture consists of a backend (database), a business tier, and a presentation tier.\n\nThe backend tier would consist of all the databases or other backend services which the application would consume.  The interface into this tier is generally some sort of database or webservice protocol (ODBC or JDBC for databases, SOAP etc. for webservices.)\n\nThe business tier is where all of the application logic and control flow resides.  This is generally where the majority of the application code lives.  The purpose of this tier is to encapsulate the logic of the application in to coarse-grained services which can be consumed by the presentation tier.  The business tier is responsible for receiving input from the presentation tier, making any necessary updates or queries to the backend tier, and providing output back to the presentation tier.  The main motivation for creating this tier and using a tierd architecture to begin with is to decouple the user interface from the backend systems used by the application.\n\nThe presentation tier encapulates the user interface.  Since your system is web based this would likely consist of ASP pages or Java servlets running on some sort of a web server.  The presentation tie serves as the single point of interface with the user and then communicates with the business tier through the services it exposes.  This communication could happen in a number of ways.  Remote object calls using something like CORBA or .Net remoting, web service invocation, or external messaging services are all options for communication between the presentation and business tiers.\n\nAs I said before, the important thing is that the presentation tier stay decoupled from the backend by interfacing only with the business tier.  This way if something about the database changes, the business tier is the only part of the application that has to change and all the user interface code can remain isolated.