Create a dimension (data warehouse parent-child relationship.)
  
  Syntax:
   CREATE DIMENSION [schema.]dimension level_clause(s) 
      [heirarchy_clause(s) attribute_clause(s)];
The command should include at least one heirarchy clause or attribute clause.
level_clause: LEVEL level IS (table.column,…) heirarchy_clause: HEIRARCHY heirarchy (child_level CHILD OF parent_level,… [join_clause]) attribute_clause: ATTRIBUTE level DETERMINES (dependent_column,…) join_clause: JOIN KEY (child_key_column,…) REFERENCES parent_level
Create Dimension Example - from jlcomp
  
  "If you don't ask the right questions, you don't get the right answers. A question asked in the right way often points to its own answer" ~ Edward Hodnett 
Related Oracle Commands:
DIMENSION - ALTER DIMENSION 
  DIMENSION - DROP DIMENSION
  MVIEW  - CREATE MATERIALIZED VIEW 
Related Views:
DBA_DEPENDENCIES ALL_DEPENDENCIES USER_DEPENDENCIES