[plt-scheme] Working with database using scheme language
Rohan Golwala schrieb:
> [...]
> I have set up a connection to the database using postgreSQL but I have a
> few questions while running the following queries:
> [...]
Hello,
maybe it will help you to read the documentation of the map, for-each
and filter procedures in the PLT's core scheme, since the methods in
spgsql are modelled after those primitives.
map and for-each simply apply the given procedure to all the values from
each database row and either collect the results in a list or discard
them. mapfilter checks whether the filter procedure applied to the row
returns a true result before it applies the other procedure.
If you simply want to see the data returned by a query, the most obvious
first choice is to pass list as the procedure argument to the map method.
cu,
Thomas