如何从 FLOWR xquery 指定 BaseX 数据库？
how to specify a BaseX database from a FLOWR xquery?
如何通过针对指定数据库的 FLOWR 查询获得 all the titles？
指定文档有效：
thufir@dur:~/basex/microsoft$
thufir@dur:~/basex/microsoft$ basex titles.xq
[warning] /usr/bin/basex: Unable to locate /usr/share/java/jing.jar in /usr/share/java
<title>Creepy Crawlies</title>
<title>Lover Birds</title>
<title>MSXML3: A Comprehensive Guide</title>
<title>Maeve Ascendant</title>
<title>Microsoft .NET: The Programming Bible</title>
<title>Midnight Rain</title>
<title>Oberon's Legacy</title>
<title>Paradox Lost</title>
<title>Splish Splash</title>
<title>The Sundered Grail</title>
<title>Visual Studio 7: A Comprehensive Guide</title>
<title>XML Developer's Guide</title>thufir@dur:~/basex/microsoft$
thufir@dur:~/basex/microsoft$
thufir@dur:~/basex/microsoft$ cat titles.xq
for $x in doc("books.xml")/catalog/book
order by $x/title
return $x/title
thufir@dur:~/basex/microsoft$
但这是针对 stand-alone xml 文档的，而不是来自 BaseX 控制台本身。如何直接在 FLOWR 中使用数据库的名称供 BaseX 引用？
>
> xquery //book[@id="bk112"]/title
<title>Visual Studio 7: A Comprehensive Guide</title>
Query executed in 1.47 ms.
>
> xquery /
<catalog>
<book id="bk101">
<author>Gambardella, Matthew</author>
<title>XML Developer's Guide</title>
<genre>Computer</genre>
<price>44.95</price>
<publish_date>2000-10-01</publish_date>
<description>An in-depth look at creating applications
with XML.</description>
</book>
<book id="bk102">
<author>Ralls, Kim</author>
<title>Midnight Rain</title>
<genre>Fantasy</genre>
<price>5.95</price>
<publish_date>2000-12-16</publish_date>
<description>A former architect battles corporate zombies,
an evil sorceress, and her own childhood to become queen
of the world.</description>
</book>
<book id="bk103">
<author>Corets, Eva</author>
<title>Maeve Ascendant</title>
<genre>Fantasy</genre>
<price>5.95</price>
<publish_date>2000-11-17</publish_date>
<description>After the collapse of a nanotechnology
society in England, the young survivors lay the
foundation for a new society.</description>
</book>
<book id="bk104">
<author>Corets, Eva</author>
<title>Oberon's Legacy</title>
<genre>Fantasy</genre>
<price>5.95</price>
<publish_date>2001-03-10</publish_date>
<description>In post-apocalypse England, the mysterious
agent known only as Oberon helps to create a new life
for the inhabitants of London. Sequel to Maeve
Ascendant.</description>
</book>
<book id="bk105">
<author>Corets, Eva</author>
<title>The Sundered Grail</title>
<genre>Fantasy</genre>
<price>5.95</price>
<publish_date>2001-09-10</publish_date>
<description>The two daughters of Maeve, half-sisters,
battle one another for control of England. Sequel to
Oberon's Legacy.</description>
</book>
<book id="bk106">
<author>Randall, Cynthia</author>
<title>Lover Birds</title>
<genre>Romance</genre>
<price>4.95</price>
<publish_date>2000-09-02</publish_date>
<description>When Carla meets Paul at an ornithology
conference, tempers fly as feathers get ruffled.</description>
</book>
<book id="bk107">
<author>Thurman, Paula</author>
<title>Splish Splash</title>
<genre>Romance</genre>
<price>4.95</price>
<publish_date>2000-11-02</publish_date>
<description>A deep sea diver finds true love twenty
thousand leagues beneath the sea.</description>
</book>
<book id="bk108">
<author>Knorr, Stefan</author>
<title>Creepy Crawlies</title>
<genre>Horror</genre>
<price>4.95</price>
<publish_date>2000-12-06</publish_date>
<description>An anthology of horror stories about roaches,
centipedes, scorpions and other insects.</description>
</book>
<book id="bk109">
<author>Kress, Peter</author>
<title>Paradox Lost</title>
<genre>Science Fiction</genre>
<price>6.95</price>
<publish_date>2000-11-02</publish_date>
<description>After an inadvertant trip through a Heisenberg
Uncertainty Device, James Salway discovers the problems
of being quantum.</description>
</book>
<book id="bk110">
<author>O'Brien, Tim</author>
<title>Microsoft .NET: The Programming Bible</title>
<genre>Computer</genre>
<price>36.95</price>
<publish_date>2000-12-09</publish_date>
<description>Microsoft's .NET initiative is explored in
detail in this deep programmer's reference.</description>
</book>
<book id="bk111">
<author>O'Brien, Tim</author>
<title>MSXML3: A Comprehensive Guide</title>
<genre>Computer</genre>
<price>36.95</price>
<publish_date>2000-12-01</publish_date>
<description>The Microsoft MSXML3 parser is covered in
detail, with attention to XML DOM interfaces, XSLT processing,
SAX and more.</description>
</book>
<book id="bk112">
<author>Galos, Mike</author>
<title>Visual Studio 7: A Comprehensive Guide</title>
<genre>Computer</genre>
<price>49.95</price>
<publish_date>2001-04-16</publish_date>
<description>Microsoft Visual Studio 7 is explored in depth,
looking at how Visual Basic, Visual C++, C#, and ASP+ are
integrated into a comprehensive development
environment.</description>
</book>
</catalog>
Query executed in 1.59 ms.
>
或使用 GUI：
对于您似乎使用的 basex 命令行脚本，您可以使用 -i 选项将命名数据库设置为上下文或为此使用输入文件，以便 basex -i mydb xquery.xq 运行您的 xquery.xq 和名为 mydb 的数据库作为查询的上下文。
根据 Martin 的回答，这是具体的 xquery 和命令：
thufir@dur:~/basex/microsoft$
thufir@dur:~/basex/microsoft$ basex -i w3school_data titles.xq
<title>Creepy Crawlies</title>
<title>Lover Birds</title>
<title>MSXML3: A Comprehensive Guide</title>
<title>Maeve Ascendant</title>
<title>Microsoft .NET: The Programming Bible</title>
<title>Midnight Rain</title>
<title>Oberon's Legacy</title>
<title>Paradox Lost</title>
<title>Splish Splash</title>
<title>The Sundered Grail</title>
<title>Visual Studio 7: A Comprehensive Guide</title>
<title>XML Developer's Guide</title>thufir@dur:~/basex/microsoft$
thufir@dur:~/basex/microsoft$
thufir@dur:~/basex/microsoft$ cat titles.xq
for $x in /catalog/book
order by $x/title
return $x/title
thufir@dur:~/basex/microsoft$
我试了一下 xquery，它成功了！谢谢马丁。
如何通过针对指定数据库的 FLOWR 查询获得 all the titles？
指定文档有效：
thufir@dur:~/basex/microsoft$
thufir@dur:~/basex/microsoft$ basex titles.xq
[warning] /usr/bin/basex: Unable to locate /usr/share/java/jing.jar in /usr/share/java
<title>Creepy Crawlies</title>
<title>Lover Birds</title>
<title>MSXML3: A Comprehensive Guide</title>
<title>Maeve Ascendant</title>
<title>Microsoft .NET: The Programming Bible</title>
<title>Midnight Rain</title>
<title>Oberon's Legacy</title>
<title>Paradox Lost</title>
<title>Splish Splash</title>
<title>The Sundered Grail</title>
<title>Visual Studio 7: A Comprehensive Guide</title>
<title>XML Developer's Guide</title>thufir@dur:~/basex/microsoft$
thufir@dur:~/basex/microsoft$
thufir@dur:~/basex/microsoft$ cat titles.xq
for $x in doc("books.xml")/catalog/book
order by $x/title
return $x/title
thufir@dur:~/basex/microsoft$
但这是针对 stand-alone xml 文档的，而不是来自 BaseX 控制台本身。如何直接在 FLOWR 中使用数据库的名称供 BaseX 引用？
>
> xquery //book[@id="bk112"]/title
<title>Visual Studio 7: A Comprehensive Guide</title>
Query executed in 1.47 ms.
>
> xquery /
<catalog>
<book id="bk101">
<author>Gambardella, Matthew</author>
<title>XML Developer's Guide</title>
<genre>Computer</genre>
<price>44.95</price>
<publish_date>2000-10-01</publish_date>
<description>An in-depth look at creating applications
with XML.</description>
</book>
<book id="bk102">
<author>Ralls, Kim</author>
<title>Midnight Rain</title>
<genre>Fantasy</genre>
<price>5.95</price>
<publish_date>2000-12-16</publish_date>
<description>A former architect battles corporate zombies,
an evil sorceress, and her own childhood to become queen
of the world.</description>
</book>
<book id="bk103">
<author>Corets, Eva</author>
<title>Maeve Ascendant</title>
<genre>Fantasy</genre>
<price>5.95</price>
<publish_date>2000-11-17</publish_date>
<description>After the collapse of a nanotechnology
society in England, the young survivors lay the
foundation for a new society.</description>
</book>
<book id="bk104">
<author>Corets, Eva</author>
<title>Oberon's Legacy</title>
<genre>Fantasy</genre>
<price>5.95</price>
<publish_date>2001-03-10</publish_date>
<description>In post-apocalypse England, the mysterious
agent known only as Oberon helps to create a new life
for the inhabitants of London. Sequel to Maeve
Ascendant.</description>
</book>
<book id="bk105">
<author>Corets, Eva</author>
<title>The Sundered Grail</title>
<genre>Fantasy</genre>
<price>5.95</price>
<publish_date>2001-09-10</publish_date>
<description>The two daughters of Maeve, half-sisters,
battle one another for control of England. Sequel to
Oberon's Legacy.</description>
</book>
<book id="bk106">
<author>Randall, Cynthia</author>
<title>Lover Birds</title>
<genre>Romance</genre>
<price>4.95</price>
<publish_date>2000-09-02</publish_date>
<description>When Carla meets Paul at an ornithology
conference, tempers fly as feathers get ruffled.</description>
</book>
<book id="bk107">
<author>Thurman, Paula</author>
<title>Splish Splash</title>
<genre>Romance</genre>
<price>4.95</price>
<publish_date>2000-11-02</publish_date>
<description>A deep sea diver finds true love twenty
thousand leagues beneath the sea.</description>
</book>
<book id="bk108">
<author>Knorr, Stefan</author>
<title>Creepy Crawlies</title>
<genre>Horror</genre>
<price>4.95</price>
<publish_date>2000-12-06</publish_date>
<description>An anthology of horror stories about roaches,
centipedes, scorpions and other insects.</description>
</book>
<book id="bk109">
<author>Kress, Peter</author>
<title>Paradox Lost</title>
<genre>Science Fiction</genre>
<price>6.95</price>
<publish_date>2000-11-02</publish_date>
<description>After an inadvertant trip through a Heisenberg
Uncertainty Device, James Salway discovers the problems
of being quantum.</description>
</book>
<book id="bk110">
<author>O'Brien, Tim</author>
<title>Microsoft .NET: The Programming Bible</title>
<genre>Computer</genre>
<price>36.95</price>
<publish_date>2000-12-09</publish_date>
<description>Microsoft's .NET initiative is explored in
detail in this deep programmer's reference.</description>
</book>
<book id="bk111">
<author>O'Brien, Tim</author>
<title>MSXML3: A Comprehensive Guide</title>
<genre>Computer</genre>
<price>36.95</price>
<publish_date>2000-12-01</publish_date>
<description>The Microsoft MSXML3 parser is covered in
detail, with attention to XML DOM interfaces, XSLT processing,
SAX and more.</description>
</book>
<book id="bk112">
<author>Galos, Mike</author>
<title>Visual Studio 7: A Comprehensive Guide</title>
<genre>Computer</genre>
<price>49.95</price>
<publish_date>2001-04-16</publish_date>
<description>Microsoft Visual Studio 7 is explored in depth,
looking at how Visual Basic, Visual C++, C#, and ASP+ are
integrated into a comprehensive development
environment.</description>
</book>
</catalog>
Query executed in 1.59 ms.
>
或使用 GUI：
对于您似乎使用的 basex 命令行脚本，您可以使用 -i 选项将命名数据库设置为上下文或为此使用输入文件，以便 basex -i mydb xquery.xq 运行您的 xquery.xq 和名为 mydb 的数据库作为查询的上下文。
根据 Martin 的回答，这是具体的 xquery 和命令：
thufir@dur:~/basex/microsoft$
thufir@dur:~/basex/microsoft$ basex -i w3school_data titles.xq
<title>Creepy Crawlies</title>
<title>Lover Birds</title>
<title>MSXML3: A Comprehensive Guide</title>
<title>Maeve Ascendant</title>
<title>Microsoft .NET: The Programming Bible</title>
<title>Midnight Rain</title>
<title>Oberon's Legacy</title>
<title>Paradox Lost</title>
<title>Splish Splash</title>
<title>The Sundered Grail</title>
<title>Visual Studio 7: A Comprehensive Guide</title>
<title>XML Developer's Guide</title>thufir@dur:~/basex/microsoft$
thufir@dur:~/basex/microsoft$
thufir@dur:~/basex/microsoft$ cat titles.xq
for $x in /catalog/book
order by $x/title
return $x/title
thufir@dur:~/basex/microsoft$
我试了一下 xquery，它成功了！谢谢马丁。