Function to Dynamically Create-Table via Clojure JDBC Not working

Question

I have a function I made to get the name of a table and the one or more columns and create the table in postgres sql. I created a static version as well to test. The static version works fine, however the dynamic verison only worked when I wrote it only to take one column as an argument. Now that I'm trying to have multiple columns as an arg it throws an exception. Here is the code:

(require '[clojure.java.jdbc :as j]
       '[clojure.java.jdbc.sql :as s])


(def db
    {:classname "org.postgresql.Driver"
     :subprotocol "postgresql"
     :subname "mydb"
     :username "username"
     :password "password"})

    (defn StaticCreateTable
      []
    (j/with-connection db
        (j/create-table "records3" 
     ["RecID", "int", "PRIMARY KEY"]
     ["TreeID", "int"]
     ["Bubba", "varchar(30)"])
         (println "Success!")))

    (defn DynamicCreateTable2
      [map]
      (j/with-connection db
        (j/create-table (:tablename map) (for [i (:columns map)] i))
        (println "Success!")))

This is what I input:

(DynamicCreateTable2 {:tablename "Creators3" 
:columns [
["CreatorID", "int", "PRIMARY KEY"]
["Number", "int"]]} )

Any help would be greatly appreciated

noisesmith · Accepted Answer · 2013-05-12 20:34:26Z

2

For starters (for [i (:columns map)] i) is the same as (:columns map)

The exception you are getting is because the columns are being passed in within a sequence, instead of being individual args to create-table.

 (apply j/create-table (:tablename map) (:columns map))

Will do what you want.

apply turns lists into individual args to its function argument.

answered May 12, 2013 at 20:34

noisesmith

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1 Comment

user1321988 Over a year ago

Thanks that did the trick, I did originally have (:columns map) but before using apply it still was not working. I appreciate it noisesmith!

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