[英]how to count the number of elements in XML?
I'm looking to get basic metadata about the data within a database.我正在寻找有关数据库中数据的基本元数据。 Specifically, the number of
line
elements which are surrouned by the root text
element.具体来说,被根
text
元素包围的line
元素的数量。
Analogous to what I'd expect COUNT
to return in SQL
-- a single integer.类似于我期望
COUNT
在SQL
返回的内容——单个整数。
the database:数据库:
thufir@dur:~/flwor/group$
thufir@dur:~/flwor/group$ basex
BaseX 9.0.1 [Standalone]
Try 'help' to get more information.
>
> open people
Database 'people' was opened in 225.24 ms.
>
> xquery /
<text>
<line>people</line>
<line>joe</line>
<line>phone1</line>
<line>phone2</line>
<line>phone3</line>
<line>sue</line>
<line>cell4</line>
<line>home5</line>
<line>alice</line>
<line>atrib6</line>
<line>x7</line>
<line>y9</line>
<line>z10</line>
</text>
Query executed in 215.13 ms.
>
> exit
See you.
thufir@dur:~/flwor/group$
Counting the lines:计算行数:
thufir@dur:~/flwor/group$
thufir@dur:~/flwor/group$ basex each.xq
1
2
3
4
5
6
7
8
9
10
11
12
13thufir@dur:~/flwor/group$
code:代码:
xquery version "3.0";
for $line in db:open("people")
for $index at $count in $line/text/line
return $count
我想你只是想使用count(/text/line)
。
From Martin's answer I see it's easy from within basex itself:从 Martin 的回答中,我认为在 basex 内部很容易:
thufir@dur:~/flwor/group$
thufir@dur:~/flwor/group$ basex
BaseX 9.0.1 [Standalone]
Try 'help' to get more information.
>
> open people
Database 'people' was opened in 208.33 ms.
>
> xquery /
<text>
<line>people</line>
<line>joe</line>
<line>phone1</line>
<line>phone2</line>
<line>phone3</line>
<line>sue</line>
<line>cell4</line>
<line>home5</line>
<line>alice</line>
<line>atrib6</line>
<line>x7</line>
<line>y9</line>
<line>z10</line>
</text>
Query executed in 237.69 ms.
>
> xquery count(/text/line)
13
Query executed in 20.55 ms.
>
> exit
See you.
thufir@dur:~/flwor/group$
but I was also looking to run it from an xq
file:但我也想从
xq
文件中运行它:
xquery version "3.0";
count(
for $line in db:open("people")
return $line/text/line)
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