This is really more of a requirements definition than a technical problem -- what you need to focus on is "how can we define the dates in the past" and the technical solution will flow.

The times I've had to approach something like this we've typically:

• Define how to map things -- like MichaelT suggests, decide that anything that is defined as Month/Day becomes defined as midnight on the 1st of said month. This is typically good enough for most purposes -- if the exact date was that important you probably would have a record of it 35 years later, right?
• Figure out if you need to track this -- IE, do records with slightly made up create dates need a flag saying so? Or is that just a user training issue so folks know and can act accordingly.

Sometimes one needs to do something like make the dates fuzzy -- for example, that may one date might need to respond to a query for anything in May 1978. This is doable -- just make your create_date 2 fields, old records get a 30 days spread as appropriate, new ones get 2 identical values.

This is really more of a requirements definition than a technical problem -- what you need to focus on is "how can we define the dates in the past" and the technical solution will flow.

The times I've had to approach something like this we've typically:

• Define how to map things -- like MichaelT suggests, decide that anything that is defined as Month/Day becomes defined as midnight on the 1st of said month. This is typically good enough for most purposes -- if the exact date was that important you probably would have a record of it 35 years later, right?
• Figure out if you need to track this -- IE, do records with slightly made up create dates need a flag saying so? Or is that just a user training issue so folks know and can act accordingly.

Sometimes one needs to do something like make the dates fuzzy -- for example, that may one date might need to respond to a query for anything in May 1978. This is doable -- just make your create_date 2 fields, old records get a 30 days spread as appropriate, new ones get 2 identical values.

This is really more of a requirements definition than a technical problem -- what you need to focus on is "how can we define the dates in the past" and the technical solution will flow.

The times I've had to approach something like this we've typically:

• Definited how to map things -- like MichaelT suggests, decide that anything that is defined as Month/Day becomes defined as midnight on the 1st of said month. This is typically good enough for most purposes -- if the exact date was that important you probably would have a record of it 35 years later, right?
• Figure out if you need to track this -- IE, do records with slightly made up create dates need a flag saying so? Or is that just a user training issue so folks know and can act accordingly.

Sometimes one needs to do something like make the dates fuzzy -- for example, that may one date might need to respond to a query for anything in May 1978. This is doable -- just make your create_date 2 fields, old records get a 30 days spread as appropriate, new ones get 2 identical values.

This is really more of a requirements definition than a technical problem -- what you need to focus on is "how can we define the dates in the past" and the technical solution will flow.

The times I've had to approach something like this we've typically:

• Define how to map things -- like MichaelT suggests, decide that anything that is defined as Month/Day becomes defined as midnight on the 1st of said month. This is typically good enough for most purposes -- if the exact date was that important you probably would have a record of it 35 years later, right?
• Figure out if you need to track this -- IE, do records with slightly made up create dates need a flag saying so? Or is that just a user training issue so folks know and can act accordingly.

Sometimes one needs to do something like make the dates fuzzy -- for example, that may one date might need to respond to a query for anything in May 1978. This is doable -- just make your create_date 2 fields, old records get a 30 days spread as appropriate, new ones get 2 identical values.