如何计算XML中的元素个数？

Question

我正在寻找有关数据库中 data 的基本元数据。具体来说，根 text 元素包围的 line 元素的数量。

类似于我期望的 COUNT 到 SQL 中的 return -- 一个整数。

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$

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$

代码：

xquery version "3.0";

for $line in db:open("people")
for $index at $count in $line/text/line
return $count

Answer 1

我想您只是想使用 count(/text/line)。

Answer 2

从 Martin 的回答中，我发现在 basex 本身内部很容易：

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$

但我也在运行从 xq 文件中寻找它：

xquery version "3.0";

count(
for $line in db:open("people")
return $line/text/line)

如何计算XML中的元素个数？

how to count the number of elements in XML?

text

xquery

count

flwor

basex