请帮忙用英语回答下下面的问题1.What're the features of Flat-File Database and Relational Database?2.What's a black box testing and white box testing?3.Discuss the features of a hub,a switch and a router.

请帮忙用英语回答下下面的问题1.What're the features of Flat-File Database and Relational Database?2.What's a black box testing and white box testing?3.Discuss the features of a hub,a switch and a router.
请帮忙用英语回答下下面的问题
1.What're the features of Flat-File Database and Relational Database?
2.What's a black box testing and white box testing?
3.Discuss the features of a hub,a switch and a router.

请帮忙用英语回答下下面的问题1.What're the features of Flat-File Database and Relational Database?2.What's a black box testing and white box testing?3.Discuss the features of a hub,a switch and a router.
1． What’re the features of Flat-File Database and Relational Database?
Flat-File:The flat-file style of database is ideal for small amounts of data that needs to be human or edited by hand .All they are made up of is a they store.The typical flat-file database is separated using a common delimiter.One of the main problems with using flat files for even a small database is the fact that it is very easy to be destroyed.
Relational:The relational databases,such as Microsoft SQL Server and Oracle,have a much more logical structure in the way that it stores data.One major advantage of the relational model is that,if a database is designed efficiently,there should be no duplication of any data,helping to maintain database integrity.Relational databases also have functions ‘built in’ that help them to get,sort and edit the data in many different ways.And so can go quite some way to speeding up the development and production of web applications.
2． What’s a black box testing and white box testing?
Black box tests are performed to assess how well a program meets its requiremens,looking for missing or incorrect functionality.So it is also called functional testing.Functional testing examines whether the output is the expected result with the valid input.It isn’t concerned with the internal structure of the program.Black Box testing is the most favoured because it is extremely difficult to test the structure of large programs.White box testing is performed to reveal problems with the internal structure of a program.This requires the tester to have detailed knowledge of the internal structure.A common goal of white-box testing is to ensure a test case exercises every path through a program.White box testing strategy takes into account the entire software implementation during testing.
3． Discuss the features of a hub,a switch and a router.
A hub is a device that provides a common connection point for a group of devices in a network.When a packet,a data piece,arrives at the hub,it is transmitted to all other network nodes connected to that hb.Similar,but more intelligent devices,are routers and switches.A switch transmits packets on a network,but instead of sending them to all nodes on the network like a hub,it sorts out the packets and only sends them to proper node.This allows each node on the network to use the full capacity of the network channel; with a hub,the network capacity is shared among the nodes.Routers are used in large WANs-like the Internet-to pass packets along to their destinations.Most data is broken down into more than one packet and the individual packets may be routed over the same or different paths-the path taken is determined by the routers on the network.When a packet is received by a router,the router passes it along to the next router.The routers on a network work together to share information about the network.If one part of the network is congested or out of service,a router can choose to send a packet by an alternate route.

太难了...