《数据库理论与技术》复习题-2008小妖版(2)

DataGuide 图

PS：此图为我自己画的，不知道是否正确，有懂行的麻烦看看！

10. For the DTD, XML, and XQUERY given below, answer the questions listed

next.

The Document Type Definition myfriend.dtd:

< !ELEMENT myfriends (person*)>

< !ELEMENT person (id, name?, cell-phone*, children?)> < !ELEMENT children (child*)> < !ELEMENT child (name,toys*)> < !ELEMENT name ( #PCDATA)> < !ELEMENT toys ( #PCDATA)> < !ELEMENT id ( #PCDATA)> ... ] < !ELEMENT employees (emp*)>

< !ELEMENT emp (id, work-phone, (contact|address)> < !ELEMENT address (city,zip,street)> < !ELEMENT id ( #PCDATA)>]

< !ELEMENT contact ( #PCDATA)> ... ]

The XML Document friends.xml:

1

``jack''

2222

2

3333

c1

c2 t1 c2 ...

The XML Document employees.xml:

1

9999 ``me''

2

8888

c z s

The XQUERY expression:

FOR $outer in (friends.xml)//person, LET $child := $outer/children

WHERE ($outer/cellphone > 2000 )

RETURN $outer/id

FOR $inner IN (employees.xml)/employees/emp[id=$outer/id] RETURN {

$outer/cellphone $child/child

$inner/workphone $inner/address/city }

1) List the XML output that the XQUERY expression would generate when

applied to the given XML input documents.

2) Design a relational schema to store the two given XML data files.

3) List the SQL query that you would generate to execute the given XQUERY

expression on your relational database. State what final computations would remain to be done by the XQUERY processor beyond executing your SQL statement, if any.

解:

1)

1

2222 9999 2

3333

c1

c2 t1 c2 8888 c

2) person(pid, cellphone, name) child(cid, parentid, name) toy(tid, cid, toy_name) emp(pid, workphone, contact, city, zip, street) 3) person(pid, name, cellphoneSet MultiSet(cellphones), ChildSet MultiSet(children)) cellphones(cellphone)

children(name, toySet MultiSet(toys)) toys(toyname)

emp(pid, workphone, contact, city, zip, street) 4) select person.cellphone,

array( select child.name child.toy form child

where child.parentid=person.pid) as child_array,

emp.workphone, emp.city from person, child, emp

where person.pid=emp.pid AND person.cellphone>2000

11. Suppose you have to represent the information about parts. Each part has a name

(unique),and a textual description. Parts may be simple or complex. A simple part has a color but no children subparts. A complex part has a number of children subparts (which can be simple or complex), each of which may be repeated. (E.g., a car has 4 wheels.) You can assume that each part can be a child subpart of at most one other part (so each part, together with its subparts, can be viewed as a tree). Do not assume any fixed number of levels of part composition. …… 此处隐藏：160字，全部文档内容请下载后查看。喜欢就下载吧 ……