OBIEE - What means "Data is dense" ?

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1 - About

When setting up a aggregate rules for a measure column, you can specify that data is dense only if all the logical table sources to which it is mapped are dense.

In a logical column if you check “Based on Dimension” (aggregating by dimension is chosen), you will have the option Data is dense.

What it means in general ? : Data Modeling - What means "Data is dense/sparse" ?

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3 - What it means in OBIEE ?

By default, data is considered sparse. However, on rare occasions you might have logical table source with dense data.

A logical table source is considered to have dense data if it has row for every combination of its associated dimension levels.

When setting up a aggregate rules for a measure column, you can specify that data is dense only if all the logical table sources to which it is mapped are dense.

Specifying data is dense when any table source that is used by this column does not contain dense data will return incorrect results

This is used for FIRST/LAST aggregation rules (of generally for SQL Function - Window Aggregate (Analytics function)) where data is dense across the time dimension, e.g. inventory values for every period. SQL generation is optimized in this case.

Specifying data is dense when any table source that is used by this column does not contain dense data will return incorrect results.