XQuery FLWOR expression

Fayilin XML na shirin

A ta ce a gudanar da fayilin "books.xml" a cikin tasiri na shirin na yanzu (daga fayilin XML na shirin na yanzu).

A ta ce gudanar da gudanar da fayilin "books.xml" a cikin nazarin shugabanci na kai tsaye..

Dake kananin FLWOR daga "books.xml" yana samar da nau'ikan:

Dake kananin hanyar yankin na yanzu shine:

doc("books.xml")/bookstore/book[price>30]/title

Dake kananin na yanzu yana gudanar da abin da yake cikin elementin book na bookstore, kuma abin da yake cikin elementin price yana da kimanin 30.

Dake kananin FLWOR na yanzu yana da kama da hanyar yankin da yake cikin hanyar yankin na yanzu:

for $x in doc("books.xml")/bookstore/book
where $x/price>30
return $x/title

Nisha-wani shine:

<title lang="en">XQuery Kick Start</title>
<title lang="en">Learning XML</title>

A ta ce gudanar da nisha-wani da ake gudanar da abin da ake samar da FLWOR:

for $x in doc("books.xml")/bookstore/book
where $x/price>30
order by $x/title
return $x/title

FLWOR shine kacalacin "For, Let, Where, Order by, Return".

for Dake kananin ya na yin abin da yake cikin elementin bookstore ya yi kama $x.

where Dake kananin ya na gudanar da abin da yake cikin elementin book wanda yake da kimanin 30.

order by Dake kananin ya na gudanar da tsarin zuriyar yankin. Za a yi gudanar da abin da yake cikin elementin title.

return 语句规定返回什么内容。在此返回的是 title 元素。

上面的 XQuery 表达式的结果：

<title lang="en">Learning XML</title>
<title lang="en">XQuery Kick Start</title>