Symbol Descriptions

[jwp]

Symbols don't provide any metadata. While statements can provide much of this information, procedure references require
some specialization wrt the exposed description.

A full description is needed:

parameter types
parameter names
optional parameters (due to procedure defaults[8.4 feature])
result types
result column names (if applicable; single column results may not have names)
result transformation/finalized type (if any; column/mapping)

How should COPY be described? o_O

I'm thinking along the lines of:

Bs.pg_description, Bs.sql_description

Where each attribute can express type identifiers in a native form...

Statements and procedures are a bit more simple than symbols, so I'm not optimistic about being able to directly reflect
their metadata attributes.

[jwp]

COPY statements should probably never be directly inside a query library. Rather, we can generate COPY's from SELECTs or from table names..

[jwp]

huh. looking at this again, I think all that's really needed is the ability specify names for the parameters, and that's only necessary for statements.

AFA defaults are concerned, I'm going to avoid them.

[jwp]

libraries are really best left for driver usage, so let's expand as the driver's needs expands.