@Override
  public int getType(ASTNode root) {
    return root.getChild(1).getType();
  }
Alter Table category helper. It derives the actual type of the command from the root element, by selecting the type
of the second child, as the Alter Table commands have this structure: tableName command partitionSpec?
ql/src/java/org/apache/hadoop/hive/ql/ddl/table/AlterTableAnalyzerCategory.java