A
data-driven lattice is a
multi-cell graph in which the cell data is determined by the values of one or more class variables.
Class variables are specified in the designer when the report designer creates a report
that includes the
lattice. The number of cells is determined by the unique values of the class variables. Each
cell of the lattice has the same graph elements. However, these graph elements have
different values of the class variables.
The following example shows a graph with data assigned to it. The custom graph object
includes a data-driven lattice with a columnar role. The graph object allows multiple
data assignments for the Measure
role.
In the report, the graph object includes a three-cell lattice of bar charts showing
engine size and miles per gallon for different types of automobiles. The country of origin
is specified as the
class variable. As a result, a cell is created for each country of origin.
Here are the characteristics
of data-driven lattices:
-
You can define up to two lattice roles: one role for the rows and another role for
the columns. When the report designer
uses the lattice in a report, the class variables are assigned to the lattice roles.
All class variables must come from a single
data source. The number of rows and columns in the graph is determined by the unique values of
the class variables.
-
If you specify that the role is
required, then a report designer must assign data to the role.
If this option is not selected, then report designers can choose whether to assign
data to the role. In that case, it is possible for a graph object to have no lattice.
-
Graph elements can be overlaid the same way they are overlaid in single-cell or
user-defined multi-cell graphs. When the report designer adds a lattice to a report, the
overlaid graph element is displayed in every cell.
-
Properties that you specify for
graph elements are applied to all of the cells of the graph object.