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Restrictions
Parallel DML on dimension table (DEPT in our example) will mark index unusable
No table can appear twice
Dimension tables must have PK or unique constraint
Index columns limited to dimension table(s)
Must include all columns of composite PK in join
IOT and TEMP tables not supported
Notes:
Join results must be stored, therefore, bitmap join indexes have the following restrictions:
Parallel DML is currently only supported on the fact table. Parallel DML on one of the participating dimension tables will mark the index as unusable.
Only one table can be updated concurrently by different transactions when using the bitmap join index.
No table can appear twice in the join.
You cannot create a bitmap join index on an index-organized table or a temporary table.
The dimension table join columns must be either primary key columns or have unique constraints.
The columns in the index must all be columns from the “dimension” table(s). Note: Bitmap join indexes can be created on any two tables, as long as there exists a PK to FK relationship. The note here about columns from the dimension table should not be construed to mean that you have to have a valid data warehouse dimension table.
If a dimension table has composite primary key, each column in the primary key must be part of the join.