Thank you very much for your reply.
I assume that in your example commands, mydoc.xml already existed as a file on your hard drive. In my case, the system looked for mydoc.xml rather than create it:
CREATE DB db1
Database 'db1' created in 14.41 ms.
ADD mydoc.xml
Resource "/home/tcd/mydoc.xml" not found.
Your 2nd ADD command worked, which I assume gives us an XML file empty apart from a root node <a/>:
ADD TO doc2.xml <a/>
Path "doc2.xml" added in 2.72 ms.
INFO STORAGE
PRE DIS SIZ ATS ID NS KIND CONTENT ------------------------------------------ 0 1 2 1 0 0 DOC doc2.xml 1 1 1 1 1 0 ELEM a
Now I'd like to add a new node to the new document. I've tried two variants as follows:
XQUERY insert node <newnode/> into <a/>
Query executed in 2.09 ms.
XQUERY insert node <newnode/> into doc('doc2.xml')/a
Stopped at ., 1/33: [FODC0002] Resource '/home/tcd/doc2.xml' does not exist.
Although the first XQUERY command appeared to work, if I export the XML file with the EXPORT command and examine it, unfortunately the new node is not present. The file just contains the <a/> node.
Is there any variation of the EXPORT command that will simply echo the contents of the XML file to the terminal, rather than to a file? If not, that would be a useful addition.
Best regards, Thomas
At 11:00 25/08/2013, you wrote:
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Today's Topics:
- Documentation (Thomas Daly)
- Re: Documentation (Dimitar Popov)
Message: 1 Date: Sat, 24 Aug 2013 16:25:17 +0100 From: Thomas Daly thomas.daly@live.com To: basex-talk@mailman.uni-konstanz.de Subject: [basex-talk] Documentation Message-ID: BLU0-SMTP12145626E8EAB6750E955A2914F0@phx.gbl Content-Type: text/plain; charset="us-ascii"; format=flowed
Hello,
Thank you for this system, which looks promising.
I would like to request better documentation to show how to do the most basic things. I am trying to create a new database and add a single new record to it. I don't want to start with a pre-written XML document. So using the command line client tool:
CREATE DB users
Database 'users' created in 214.89 ms.
Then I refer to the ADD command http://docs.basex.org/wiki/Commands#ADD which suggests an XML string can be added. So I try:
ADD <record>hello</record>
Name '' is invalid.
All the examples of ADD involve adding existing XML files. A path to the database is referred to, but having just created the database I have no idea what the path is.
Referring to tutorials and slides on page http://docs.basex.org/wiki/Getting_Started, the link to XMLPrague 2013 is broken. BaseX adventures starts at an advanced level of querying a host of XML files. W3Schools XQuery seems all about querying existing databases, I can't find anything on how to add or update a single record.
I'm sure with enough trial and error I'll work out how to do it. My point is that I feel it ought to be more obvious how to carry out the most basic CRUD operations.
Best regards, Thomas
Message: 2 Date: Sat, 24 Aug 2013 23:31:36 +0200 From: Dimitar Popov dp@basex.org To: basex-talk@mailman.uni-konstanz.de Subject: Re: [basex-talk] Documentation Message-ID: 1377379896.5833.0.camel@darkrider Content-Type: text/plain; charset="UTF-8"
On Sat, 2013-08-24 at 16:25 +0100, Thomas Daly wrote:
Hello,
Thank you for this system, which looks promising.
I would like to request better documentation to show how to do the most basic things. I am trying to create a new database and add a single new record to it. I don't want to start with a pre-written XML document. So using the command line client tool:
CREATE DB users
Database 'users' created in 214.89 ms.
Then I refer to the ADD command http://docs.basex.org/wiki/Commands#ADD which suggests an XML string can be added. So I try:
ADD <record>hello</record>
Name '' is invalid.
All the examples of ADD involve adding existing XML files. A path to the database is referred to, but having just created the database I have no idea what the path is.
BaseX supports the notion of collections, i.e. one can store multiple XML documents into a single database. Each non-empty database contains at least one document. Each stored document must have a name. This is the reason why when calling the ADD command with an XML fragment one must specify the name of the new document. However, if a file is specified as input, then the file name is implicitly used as a name of the new document.
Similar behavior has the CREATE DB command. If called with a file, then a document with the name of the file will be created. If called with an XML fragment, then the database name will be used as the name of the first document. The following examples illustrate the two commands:
CREATE DB db1
Database 'db1' created in 68.92 ms.
INFO STORAGE
PRE DIS SIZ ATS ID NS KIND CONTENT
ADD mydoc.xml
Path "mydoc.xml" added in 15.36 ms.
INFO STORAGE
PRE DIS SIZ ATS ID NS KIND CONTENT
0 1 2 1 0 0 DOC mydoc.xml 1 1 1 1 1 0 ELEM a
ADD TO doc2.xml <a/>
Path "doc2.xml" added in 4.5 ms.
INFO STORAGE
PRE DIS SIZ ATS ID NS KIND CONTENT
0 1 2 1 0 0 DOC mydoc.xml 1 1 1 1 1 0 ELEM a 2 3 2 1 2 0 DOC doc2.xml 3 1 1 1 3 0 ELEM a
CREATE DB db2 mydoc.xml
Database 'db2' created in 12.57 ms.
INFO STORAGE
PRE DIS SIZ ATS ID NS KIND CONTENT
0 1 2 1 0 0 DOC mydoc.xml 1 1 1 1 1 0 ELEM a
CREATE DB db3 <a/>
Database 'db3' created in 13.6 ms.
INFO STORAGE
PRE DIS SIZ ATS ID NS KIND CONTENT
0 1 2 1 0 0 DOC db3.xml 1 1 1 1 1 0 ELEM a
Referring to tutorials and slides on page http://docs.basex.org/wiki/Getting_Started, the link to XMLPrague 2013 is broken.
Thanks, I fixed the link. Please, report such inaccuracies or feel free to edit the wiki yourself.
BaseX adventures starts at an advanced level of querying a host
of XML files. W3Schools XQuery seems all about
querying existing databases
The BaseX documentation contains only the BaseX specific functionality - the purpose is not to duplicate the W3C specification or the tutorials at W3Schools. However, XQuery questions are readily answered on the mailing list ;)
I can't find anything on how to add or update a single record.
The XQuery Update Facility might be helpful to you [1].
I'm sure with enough trial and error I'll work out how to do it. My point is that I feel it ought to be more obvious how to carry out the most basic CRUD operations.
I couldn't agree more. On the other hand the BaseX team gives its best to maintain the documentation and is always open to improvement suggestions. So if you have any concrete ideas how the documentation can be made more useful, they will be most welcome.
Regards, Dimitar
[1] http://www.w3.org/TR/xquery-update-10/
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End of BaseX-Talk Digest, Vol 44, Issue 24
On Sun, 2013-08-25 at 16:42 +0100, Thomas Daly wrote:
Thank you very much for your reply.
I assume that in your example commands, mydoc.xml already existed as a file on your hard drive.
Yes, that's right, I wanted to show the two modes in which the ADD command work: with a file and with an XML fragment.
In my case, the system looked for mydoc.xml rather than create it:
CREATE DB db1
Database 'db1' created in 14.41 ms.
ADD mydoc.xml
Resource "/home/tcd/mydoc.xml" not found.
Currently, it is not possible to use the ADD command to create an empty document.
Your 2nd ADD command worked, which I assume gives us an XML file empty apart from a root node <a/>:
ADD TO doc2.xml <a/>
Path "doc2.xml" added in 2.72 ms.
INFO STORAGE
PRE DIS SIZ ATS ID NS KIND CONTENT
0 1 2 1 0 0 DOC doc2.xml 1 1 1 1 1 0 ELEM a
Now I'd like to add a new node to the new document. I've tried two variants as follows:
XQUERY insert node <newnode/> into <a/>
Query executed in 2.09 ms.
This query does not update the database. What it does is to create an XML fragment <a/> in the main memory and insert the node <newnode/> in it. What you need is:
XQUERY insert node <newnode/> into /a
Check the XQuery Update Facility and section "3.7.1 Direct Element Constructors" of the XQuery spec [1] for more details.
XQUERY insert node <newnode/> into doc('doc2.xml')/a
Stopped at ., 1/33: [FODC0002] Resource '/home/tcd/doc2.xml' does not exist.
The path in the argument of the fn:doc() function must contain the database name, because the function can be used to access data from different databases within a single query. In your case it should look like this:
XQUERY insert node <newnode/> into doc('db1/doc2.xml')/a
Although the first XQUERY command appeared to work, if I export the XML file with the EXPORT command and examine it, unfortunately the new node is not present. The file just contains the <a/> node.
See my answer above: since your query did not change the database, the EXPORT command does not do what you expect.
Is there any variation of the EXPORT command that will simply echo the contents of the XML file to the terminal, rather than to a file? If not, that would be a useful addition.
That should do the job:
XQUERY doc('db1/doc2.xml')
Regards, Dimitar
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Dimitar Popov -
Thomas Daly