Re: [Chicken-users] Request for comments on the SQLite3 egg API

[Thomas Christian Chust]

John Cowan wrote:
> Thomas Christian Chust scripsit:
> 
>>   1. Introduce a new separate singleton type for SQL NULL values and
>>      refrain from using booleans altogether, because there is no SQL
>>      boolean type in SQLite3.
> 
> I favor a variant of this:  introduce a singleton type for SQL NULL
> values, and map #t and #f inbound to 1 and 0 respectively (but not
> outbound, of course).  Ideally, the singleton type would be the same
> in all SQL eggs rather than SQLite-specific: one could use the symbol
> sql:null or even the empty list, which some people already pronounce
> "nil".

Hello John,

as some database engines have an SQL list type, some Schemes make no
difference between #f and () and one of the main reasons for this change
would be compatibility, I don't think the empty list would be a good
choice for the object representing NULL.

Maybe one could use the return value of (void), which really has a very
similar meaning in Scheme as NULL has in SQL -- with the notable
exception that Scheme has no ternary logic like most SQL engines.

>>   2. Keep the data extraction routines returning #f to represent NULL
>>      but add an arbitrary default specialization of sqlite3:bind! on
>>      booleans that represents #f as NULL and #t as 1.
> 
> This has absolutely no virtues in my mind except backward compatibility.
> It's extremely unnatural.

I agree, but backward compatibility may be a big issue.

cu,
Thomas


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