does Database.HDBC support named parameters?

Question

I don't like relying on positional parameters, is it possible to do so with HDBC?

I could see passing [(String, SqlValue)] instead of [SqlValue] as arguments to the various executing functions of this package.

In a nutshell, I'd rather

select 
  t.f1
  , t.f2
  , t.f3
from
  schema.table t
where
 t.f1 > @param1
 and t.f2 < @param2

than

select 
  t.f1
  , t.f2
  , t.f3
from
  schema.table t
where
 t.f1 > ?
 and t.f2 < ?

Answer 1

Not with hdbc directly but i do it with the help of the shakespeare-text package:

quickQuery cn (T.unpack
                 [st|select bar, baz, foo
                       from table1 r
                      inner join location l on r.locat_id = l.location_id
                      where r.record_id = #{pageIdxId page}
                        and foo > #{var1 + var2}
                      order by 1|]) []

Notice haskell variables and expressions in #{} placeholders.

be careful with string splicing though.

use sql escaping function with string values.

sqlEscape :: Text -> Text
sqlEscape = T.replace "'" "''" 

then

[st|update foo set bar = '#{sqlEscape someString}' where recid = #{myRecId}|]

Or if you are up to the task, you can take the shakespeare-text library and add a small change to it to automatically escape all isString types.