Difference between revisions of "Databases"

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==Introduction==
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==Create Databases==
In BaseX, there are two kinds of databases. It is possible to have
 
databases with single XML documents and databases with a bunch of XML files, called ''Collections''.
 
  
===Creation of a database===
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In BaseX, a single database can contain one or more XML documents, called ''Collection'', and raw (binary) files.
You can create a database either within the GUI or in the console version of BaseX.
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New databases can either be created within the GUI or in the console version of BaseX:
 
   
 
   
*[[Startup#BaseX GUI|GUI]]: Go to ''Database'' → ''New'' and then press Browse to choose a file and press OK  
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* [[Startup#BaseX GUI|GUI]]: Go to ''Database'' → ''New'', press ''Browse'' to choose a file or directory, and press ''OK''
*[[Startup#BaseX Standalone|Console]]: enter <code>basex -c "CREATE DB dbname /path/to/file"</code><br/>
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* [[Startup#BaseX Standalone|Console]]: enter <code>basex -c "CREATE DB dbname /path/to/resources"</code><br/>
  
==Collection==  
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==Manage Collections==
  
===Creation of a collection===
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Once you have created a database, additional commands exist to modify its contents:
You can create a collection either within the GUI or in the console version of BaseX.  
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* XML documents can be added with the <code>[[Commands#ADD|ADD]]</code> command.
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* Raw files are added with <code>[[Commands#STORE|STORE]]</code>.
*GUI: Go to ''Database'' → ''New'' and then press Browse to choose a directory and press OK
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* Resources can be replaced with others using the <code>[[Commands#REPLACE|REPLACE]]</code> command.
*Console: enter <code>basex -c "CREATE DB dbname /path/to/collection"</code><br/>
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* Resources can be deleted with the <code>[[Commands#DELETE|DELETE]]</code> command.
  
===Manage Collections===
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The following commands create an empty database, add two resources and finally delete them again:
Additional to the creation with your choosen xml files you can start with creating an empty
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<pre>
collection and then add your xml files to it. Note that the <code>[[Commands#ADD|ADD]]</code>
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CREATE DB example
and <code>[[Commands#DELETE|DELETE]]</code> commands refer to the currently opened database.
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ADD example.xml
 
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ADD TO images/ 123.jpg
Console:
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DELETE /
* Create an empty database: <code>CREATE DB example</code>
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</pre>
* Add a document: <code>ADD example.xml</code>
 
* Delete a document: <code>DELETE example.xml</code>  
 
 
 
GUI:
 
In the GUI you can execute all above operations in the Database menu.
 
  
Once you have created a database, you may as well use the BaseX-specific [[Database Functions|XQuery Database Functions]] to add or delete XML documents:
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You may as well use the BaseX-specific [[Database Functions|XQuery Database Functions]] to add, replace and delete XML documents:
  
 
<pre class="brush:xquery">
 
<pre class="brush:xquery">
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</pre>
 
</pre>
  
===Access documents in collections===
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Last but not least, XML documents can also be added via the GUI and the ''Database'' menu.
The XQuery <code>collection()</code> function can be used to access documents in collections:  
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==Access Documents==
*Returning all documents of collection ("dbname"):<br/> <code>for $doc in collection("dbname") return base-uri($doc)</code>  
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*Access a specific document ("test") in collection ("dbname"):<br/> <code>collection("dbname/test")//*</code>
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Various XQuery functions exist to access the XML documents in databases and other locations:
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* <code>db:open("dbname", "/path/to/docs")</code>: returns documents that are found in the specified database</code>  
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* <code>collection("path/to/docs")</code>: returns the documents that are either found in the specified database or file path</code>  
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* <code>doc("path/to/document.xml")</code>: returns a single document found at the specified location. If a database exists for the specified file, it is opened instead.</code>
  
 
[[Category:Beginner]]
 
[[Category:Beginner]]

Revision as of 17:19, 13 October 2011

Create Databases

In BaseX, a single database can contain one or more XML documents, called Collection, and raw (binary) files. New databases can either be created within the GUI or in the console version of BaseX:

  • GUI: Go to DatabaseNew, press Browse to choose a file or directory, and press OK
  • Console: enter basex -c "CREATE DB dbname /path/to/resources"

Manage Collections

Once you have created a database, additional commands exist to modify its contents:

  • XML documents can be added with the ADD command.
  • Raw files are added with STORE.
  • Resources can be replaced with others using the REPLACE command.
  • Resources can be deleted with the DELETE command.

The following commands create an empty database, add two resources and finally delete them again:

CREATE DB example
ADD example.xml
ADD TO images/ 123.jpg
DELETE /

You may as well use the BaseX-specific XQuery Database Functions to add, replace and delete XML documents:

for $file in file:list("/path/to/xml/documents")
return db:add("database", $file)

Last but not least, XML documents can also be added via the GUI and the Database menu.

Access Documents

Various XQuery functions exist to access the XML documents in databases and other locations:

  • db:open("dbname", "/path/to/docs"): returns documents that are found in the specified database
  • collection("path/to/docs"): returns the documents that are either found in the specified database or file path
  • doc("path/to/document.xml"): returns a single document found at the specified location. If a database exists for the specified file, it is opened instead.