Two types of crosstabs – PB Docs 125

Dynamic crosstabs

With dynamic crosstabs, PowerBuilder builds all the columns
and rows in the crosstab dynamically when you run the crosstab.
The number of columns and rows in the crosstab match the data that
exists at runtime.

Using the preceding crosstab as an example, if a new printer
was added to the database after the crosstab was saved, there would
be an additional row in the crosstab when it is run. Similarly,
if one of the quarter’s results was deleted from the database
after the crosstab was saved, there would be one less column in
the crosstab when it is run.

By default, crosstabs you build are dynamic.

Static crosstabs

Static crosstabs are quite different from dynamic crosstabs. With static crosstabs, PowerBuilder establishes
the columns in the crosstab based on the data in the database when
you define the crosstab. (It does this by retrieving data
from the database when you initially define the crosstab.) No matter
what values are in the database when you later run the crosstab,
the crosstab always has the same columns as when you defined it.

Using the preceding crosstab as an example, if there were
four quarters in the database when you defined and saved the crosstab,
there would always be four columns (Q1, Q2, Q3, and Q4) in the crosstab
at runtime, even if the number of columns changed in the database.

Advantages of dynamic crosstabs

Dynamic crosstabs are used more often than static crosstabs,
for the following reasons:

• You
  can define dynamic crosstabs very quickly because no database access
  is required at definition time.

• Dynamic crosstabs always use the current data to
  build the columns and rows in the crosstab. Static crosstabs show
  a snapshot of columns as they were when the crosstab was defined.

• Dynamic crosstabs are easy to modify: all properties
  for the dynamically built columns are replicated at runtime automatically.
  With static crosstabs, you must work with one column at a time.