Re: [boost] SQL: next iteration of sqlpp11

On Mon, Feb 3, 2014 at 6:27 PM, Roland Bock wrote:

On 2014-02-03 18:22, Johan Baltié wrote:

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On Mon, Feb 3, 2014 at 5:56 PM, Klaim - Joël Lamotte

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On Mon, Feb 3, 2014 at 5:33 PM, Edward Diener

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wrote: In most usecases I encountered so far, it is totally OK to interpret

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NULL values like default values, e.g. NULL strings and empty strings, or NULL foreign keys or 0LL. For those usecases it would be quite annoying to have to check if there really is a value, or always use get_optional_value_or...

You are wrong ! Having a database NULL value is completely different from having an empty string or a 0 value. Please reconsider. The boost::optional is the correct choice.

+1

I do agree. NULL means "no data", not "0".In SQL "NULL = NULL" is false.

Oracle chose empty string to be equivalent to NULL and it's quite a pain to handle from a developper point of view.

Yeah, heard of that. And it would certainly be bad, if sqlpp11 did the same. It does not.

If you want to interpret NULL as NULL, fine, use the .is_null() method to check.

If you want to interpret NULL as "" or 0, also fine, just get the value.

I think all the DBMS provide a way to check that internally (NVL(column, default_value) for Oracle). What bother me is that you can have quite easily inconsistent behaviors. You retrieve values and you work with them in a select, you have no warning that a null value was encountered but you have no result or worse the wrong ones... It should not be the default behavior. -- Cheers Johan