On Wed, Feb 25, 2015 at 1:08 PM, Cecil Westerhof <cldwester...@gmail.com> wrote:
> > > 2015-02-25 18:14 GMT+01:00 Andy Fingerhut <andy.finger...@gmail.com>: > >> doseq does not have anything precisely like C/Java/Perl/etc.'s 'break' or >> 'continue'. The closest thing might be the :while keyword. You can see >> some one example of its use near the end of the examples on this page: >> http://clojuredocs.org/clojure.core/doseq >> >> The best way I know to get such behavior is to use Clojure's loop, where >> if/when/whatever-conditional-statements-you-wish can used to control >> explicitly to do another loop iteration using recur, or not. >> > > I made the following with loop: > (defn do-show-table > [table] > (loop [all-tables (show-tables db-spec)] > (let [this-table (get (first all-tables) :table_name)] > (if (= all-tables ()) > (printf "Table not found: %s\n" table) > (if (= (lower-case table) (lower-case this-table)) > (let [format "%-20s %-30s %-5s %-5s %-20s\n"] > (printf "Table %s:\n" table) > (printf format "Field" "Type" "Null?" "Key" "Default") > (doseq [{:keys [field type null key default]} > (jdbc/query db-spec [(str "SHOW COLUMNS FROM " > table)])] > Please don't get into the habit of doing db queries like this, you're one "Little Bobby Tables" away from an sql injection. In this case you should do (jdbc/query db-spec ["SHOW COLUMNS FROM ?" table]). I think you would be well-served by a general clojure principle here of trying to get the data you're are dealing within into "values" as quickly as possible, and then working with those. Rather than inter-mixing your querying and display as you're doing here, I would design this as a query to fill some maps describing your tables, and then use clojure.pprint/print-table to print out the resulting map when desired. --Aaron > (printf format field type null key default)) > (println)) > (recur (rest all-tables))))))) > > It solves both problems. > > > On Wed, Feb 25, 2015 at 8:59 AM, Cecil Westerhof <cldwester...@gmail.com> >> wrote: >> >>> At the moment I have the following function: >>> (defn do-show-table >>> [table] >>> (doseq [{:keys [table_name]} (show-tables db-spec)] >>> (when (= (lower-case table) (lower-case table_name)) >>> (let [format "%-20s %-30s %-5s %-5s %-20s\n"] >>> (printf format "Field" "Type" "Null?" "Key" "Default") >>> (doseq [{:keys [field type null key default]} >>> (jdbc/query db-spec [(str "SHOW COLUMNS FROM " >>> table)])] >>> (printf format field type null key default)))))) >>> >>> In this case it is not very important, because the outer sequence will >>> not be very big. But I would like to leave the doseq at the moment that the >>> when is executed. It will be done 0 or 1 times, so after it is done, there >>> is no use in continuing the sequence walk. >>> >>> The second part is that I would like to do an action if it is done 0 >>> times after the doseq. Is this possible? >>> >> > -- > Cecil Westerhof > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
