Using VoltDB

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Appendix E. Project Definition File (project.xml)

The project definition file (frequently referred to as project.xml), describes the structure of a VoltDB database, including the location of the database schema and stored procedures, the partitioning keys for individual tables, and other characteristics. This appendix describes the syntax for each of these components within the project definition file.

E.1. Understanding XML Syntax

The project definition file is a fully-conformant XML file. XML files consist of a series of nested elements identified by beginning and ending "tags". The beginning tag is the element name enclosed in angle brackets and the ending tag is the same except that the element name is preceded by a slash. For example:

<project>
   <database>
   </database>
</project>

Elements can be nested. In the preceding example database is a child of the element project.

Elements can also have attributes that are specified within the starting tag by the attribute name, an equals sign, and its value enclosed in single or double quotes. In the following example the database element is assigned a value of "database" for its name attribute:

<project>
   <database name="database">
   </database>
</project>

Finally, as a shorthand, elements that do not contain any children can be entered without an ending tag by adding the slash to the end of the initial tag. In the following example, the procedure tags use this form of shorthand:

<project>
   <database name="database">
      <procedures>
         <procedure class="procs.myproc1" />
         <procedure class="procs.myproc2" />
      </procedures>
   </database>
</project>

For complete information about the XML standard and XML syntax, see the official XML site at http://www.w3.org/XML/.

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