Add dependencies to a new element :

<CREATE>
  <MEDIA>
    <INFO>
      <MEDIATYPE>Gallery</MEDIATYPE>
    </INFO>
    <DEPENDENCIES>
      <DEPENDENCY type="mediaContent">
        <MEDIA ID="25"/>
        <MEDIA ID="26"/>
      </DEPENDENCY>
    </DEPENDENCIES>
  </MEDIA>
</CREATE>

Medias 25 and 26 are two existing Pictures that we add in a new Gallery.

Add dependencies on an existing element :

<UPDATE>
  <MEDIA ID="12>
    <DEPENDENCIES>
      <DEPENDENCY type="mediaContent">
        <MEDIA ID="25"/>
        <MEDIA ID="26"/>
      </DEPENDENCY>
    </DEPENDENCIES>
  </MEDIA>
</UPDATE>

Notice that any former dependencies of the same type are suppressed and replaced by the new ones. If you want to add a dependency without suppressing the existing ones, do it this way :

<UPDATE>
  <MEDIA ID="12">
    <DEPENDENCIES>
      <DEPENDENCY type="mediaContent" operation="append">
        <MEDIA ID="27"/>
      </DEPENDENCY>
    </DEPENDENCIES>
  </MEDIA>
</UPDATE>

In the same way if you only want to remove a former dependency on an element and leave the other dependencies of this element untouched, you will write :

<UPDATE>
  <MEDIA ID="12">
    <DEPENDENCIES>
      <DEPENDENCY type="mediaContent" operation="remove">
        <MEDIA ID="27"/>
      </DEPENDENCY>
    </DEPENDENCIES>
  </MEDIA>
</UPDATE>

Put an element in the dependencies of another :

A dependency is oriented from the parent to the child, when you assign a dependency on an element, it means it becomes the parent of the other element. In some cases, you'll want the opposite : to mark an element as the child of another.

<UPDATE>
  <MEDIA ID="27">
    <DEPENDENCIES>
      <DEPENDENCY type="mediaContent" mode="reverse">
        <MEDIA ID="12"/>
      </DEPENDENCY>
    </DEPENDENCIES>
  </MEDIA>
</UPDATE>

This query executes exactly the same operation as the previous example (see upper) : the Media 27 is now a child of the Media 12. Notice that in reverse mode, the new child is automatically appended to the other ones, it doesn't replace them.

Additional Information about a dependency

If you want to save information that concerns the relationship between two elements, you can save it in the dependency.

Ex 1: the numbers of items of a certain product in a shopping basket

Ex 2: the number of times a client downloaded a document

<UPDATE>
  <MEDIA ID="12">
    <DEPENDENCIES>
      <DEPENDENCY type="mediaContent" operation="append">
        <MEDIA ID="27">
           <DEPINFO>3</DEPINFO>
        </MEDIA>
      </DEPENDENCY>
    </DEPENDENCIES>
  </MEDIA>
</UPDATE>

This system is ideal for shopping basket : you create a Basket mediatype , a Product mediatype and you create dependencies between the basket and the products, with the number of items on the dependency.

The DEPINFO field will be returned when you use a SEARCH or a GET. It can be a number or a string.

If you already have saved a number on a dependency and only want to increase it (instead of giving its new value litterally), you can use this notation :

<UPDATE>
  <MEDIA ID="12">
    <DEPENDENCIES>
      <DEPENDENCY type="mediaContent" operation="append">
        <MEDIA ID="27">
           <DEPINFO operator="++"/>
        </MEDIA>
      </DEPENDENCY>
    </DEPENDENCIES>
  </MEDIA>
</UPDATE>

You can use all the operators available for UPDATE : discover them here.
Ex: <DEPINFO operator="+">9</DEPINFO>

If you need to save a second information, you can use the second field called COMMENT.

<UPDATE>
  <MEDIA ID="12">
    <DEPENDENCIES>
      <DEPENDENCY type="mediaContent" operation="append">
        <MEDIA ID="27">
           <DEPINFO operator="++"/>
           <COMMENT>Made on 2006-05-03</COMMENT>
        </MEDIA>
      </DEPENDENCY>
    </DEPENDENCIES>
  </MEDIA>
</UPDATE>

It can be a number or a string.