Cannot resolve group 'DatabaseViewPopupMenu' in my plugin.xml Follow

I write a idea plugin for database tools. And I add an action group to the group that id is 'DatabaseViewPopupMenu'. But in the plugin,xml file, the idea shows me cannot resolve group 'DatabaseViewPopupMenu'.I don't know what cause that.

Another error is that cannot resolve plugin com.intellij.database.

The following is the xml.

<depends optional="true">com.intellij.modules.ultimate</depends>
<depends>com.intellij.database</depends>

<actions>
  <!-- Add your actions here -->
  <group id="ConvertCharsetActionGroup"
    class="ConvertCharsetActionGroup" text="Convert Charset"
    description="Convert charset for database">
    <add-to-group group-id="DatabaseViewPopupMenu" anchor="last"/>
  </group>
</actions>

I have searched a lot, but nothing helps. Can anyone awesome help me? Thx!!!