Hi:

The gist of my question: is there a way to *portably* store and retrieve

Infinity in an ActiveRecord float column?

Following is an amusing saga, but it doesn’t really answer the question.

Step 1: As was mentioned in http://www.ruby-forum.com/topic/74141, you

can’t simply write a Ruby infinite value. Here are the results in Rails

3 with the sqlite 1.3.3 gem:

r = TestRec.create(:x => (1.0/0.0))

ActiveRecord::StatementInvalid: SQLite3::SQLException: no such column:

Infinity: INSERT INTO “test_recs” (“x”) VALUES (Infinity)

Step 2: So if storing infinity isn’t possible, how about a really big

value, like Float::MAX?

r = TestRec.create(:x => Float::MAX)

=> #<TestRec id: 1, x: 1.7976931348623157e+308>r.x == Float::MAX

=> true

Step 3: That looks promising, but we’re looking at the in-memory version

of the record. We should reload r to get the value from the database:

r.reload

=> #<TestRec id: 1, x: Infinity>r.x == Float::MAX

=> falser.x.infinite?

=> 1

Whoa! x has changed from Float::MAX to Infinity. So it appears that if

you want to store Infinity in a DB column, you need to store Float::MAX

instead. At least for sqlite.

Naturally, I don’t trust this as a general solution. Can I assume it

will work this way across other DBs? If not, is there a generally

portable way to store Infinity?