Extending support for jsonb with clojure.jdbc and clojure/data.json

Question

This is my first foray into Clojure (and functional programming altogether) and I'm trying to extend support for JSONB using clojure.jdbc library. I've been using this as a guide:

http://niwibe.github.io/clojure.jdbc/#_extend_sql_types

Also using leinengen so I have my dependencies setup with the following:

[org.clojure/clojure "1.6.0"]
[clj-http "0.9.1"]
[clojure.jdbc "0.3.1"]
[postgresql "9.3-1102.jdbc41"]
[org.clojure/data.json "0.2.5"]

Then I have my code which looks like this:

(require '[jdbc.proto])
(require '[clojure.data.json :as json])
(import 'org.postgresql.util.PGobject)

(extend-protocol jdbc.proto/ISQLType 
  clojure.lang.IPersistentMap

  (set-stmt-parameter! [this conn stmt index]
    (let [prepared-value (as-sql-type this conn)]
      (.setObject stmt index prepared-value)))

  (as-sql-type [this conn]
    (doto (PGobject.)
      (.setType "jsonb")
      (.setValue (json/write-str)))))

When I run the REPL and try to run my load file command like

(load-file "src/db/jdbc-types-jsonb.clj")

The compiler complaines with this error:

CompilerException java.lang.RuntimeException: Unable to resolve symbol: as-sql-type in this context, compiling:(/Users/akmiller/Source/personal/clojure-pg/src/db/jdbc-types-jsonb.clj:14:26)

I'm trying to understand why it doesn't see as-sql-type as 'this' at that point should be the protocol correct? Sorry if this is a noob type issue (I'm sure it is) but I just don't see the issue and I need some Clojure expertise to help me get past this very small hurdle!

link to extend sql types doc is broken. The possible replacement is this one: funcool.github.io/clojure.jdbc/0.4.x/#_extend_sql_types — Frank Henard
– Frank Henard, Commented Aug 12, 2015 at 14:41

Adam · Accepted Answer · 2014-11-08 19:47:27Z

2

I was able to fix the issue by changing this line:

(let [prepared-value (as-sql-type this conn)]

to this:

(let [prepared-value (jdbc.proto/as-sql-type this conn)]

I'm still not sure why, in this case, I'd need to fully qualify the function name since this should reference the type I was extending (or so I thought). If someone has any more clarification on why it needs to be qualified there I'd be glad to hear it.

answered Nov 8, 2014 at 19:47

Adam

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1 Comment

Frank Henard Over a year ago

I'm not sure if this answers your question, because it might be obvious. as-sql-type needs to be qualified because it is a var in the jdbc.proto namespace.

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