Suppose you have two sets of conceptual entities:

• MarketPriceDataSet which has multiple ForwardPriceEntries
• PoolPriceForecastDataSet which has multiple PoolPriceForecastEntry

Both different child objects have near identical fields:

ForwardPriceEntry has

• StartDate
• EndDate
• SimulationItemId
• ForwardPrice
• MarketPriceDataSetId (foreign key to parent table)

PoolPriceForecastEntry has

• StartDate
• EndDate
• SimulationItemId
• ForecastPoolPrice
• PoolPriceForecastDataSetId (foreign key to parent table)

If I modelled them as separate tables, the only difference would be the foreign key, and the name of the price field.

There has been a debate as to whether the two near identical tables should be merged into one.

Options I've thought of to model this is:

• Just keep them as two independent, separate tables
• Have both sets in the one table with an additional "type" field, and a parent_id equalling a foreign key to either parent table. This would sacrifice referential integrity checks.
• Have both sets in the one table with an additional "type" field, and create a complicated sequence of joining tables to maintain referential integrity.

What do you think I should do, and why?