code: private String getFromClause(String schemaName, String tableName)
      {
          String clause = tableName;
          if (schemaName != null && !schemaName.isEmpty())
          {
              clause = schemaName + "." + tableName;
          }
          return clause;
      }
docs: Gets the from clause.
  
  @param schemaName
  the schema name
  @param tableName
  the table name
  @return the from clause