[cascalog-user] Cascalog JDBCTap problems inserting into MySQL

I thought I'd also just update this post with a stack trace. I'm running it
in Emacs via swank:

Tap.java:310 cascading.tap.Tap.outgoingScopeFor
ElementGraph.java:589 cascading.flow.planner.ElementGraph.resolveFields
ElementGraph.java:571 cascading.flow.planner.ElementGraph.resolveFields
HadoopPlanner.java:215 cascading.flow.hadoop.planner.HadoopPlanner.buildFlow
FlowConnector.java:454 cascading.flow.FlowConnector.connect
api.clj:190 cascalog.api/compile-flow
RestFn.java:137 clojure.lang.RestFn.applyTo
core.clj:601 clojure.core/apply
api.clj:204 cascalog.api/?-
RestFn.java:436 clojure.lang.RestFn.invoke
NO_SOURCE_FILE:1 paduka.db-tap/eval2418
Compiler.java:6511 clojure.lang.Compiler.eval
Compiler.java:6477 clojure.lang.Compiler.eval
core.clj:2797 clojure.core/eval
core.clj:532 swank.core/eval786[fn]
MultiFn.java:163 clojure.lang.MultiFn.invoke
basic.clj:54 swank.commands.basic/eval-region
basic.clj:44 swank.commands.basic/eval-region
basic.clj:73 swank.commands.basic/eval974[fn]
Var.java:415 clojure.lang.Var.invoke
(Unknown Source) paduka.db-tap/eval2416
Compiler.java:6511 clojure.lang.Compiler.eval
Compiler.java:6477 clojure.lang.Compiler.eval
core.clj:2797 clojure.core/eval
core.clj:100 swank.core/eval-in-emacs-package
core.clj:256 swank.core/eval-for-emacs
Var.java:423 clojure.lang.Var.invoke
AFn.java:167 clojure.lang.AFn.applyToHelper
Var.java:532 clojure.lang.Var.applyTo
core.clj:601 clojure.core/apply
core.clj:107 swank.core/eval-from-control
core.clj:330 swank.core/spawn-worker-thread[fn]
AFn.java:159 clojure.lang.AFn.applyToHelper
AFn.java:151 clojure.lang.AFn.applyTo
core.clj:601 clojure.core/apply
core.clj:326 swank.core/spawn-worker-thread[fn]
RestFn.java:397 clojure.lang.RestFn.invoke
AFn.java:24 clojure.lang.AFn.run
Thread.java:662 java.lang.Thread.run

A few things.

1) your output is only "?id" field.
2) the fields name need to have question mark in front, whereas the SQL
column name must not. Otherwise the tap couldn't find the fields or SQL
complains, respectively.
3) you need to define your table in a SQL sink.

Try this:

(defn mysql-tap [] (let [scheme (JDBCScheme. (Fields. (into-array String
["?id"])) (into-array String ["id"]))
table-desc (TableDesc. "tweets" (into-array String ["?id"])
(into-array String ["id"]) (into-array String []))
tap (JDBCTap.
"jdbc:mysql://localhost:3306/burn?user=root&password="
"com.mysql.jdbc.Driver" table-desc scheme )]
tap))

Hi Paul,

Thank you so much for your help! that's fixed it and it's now happily
inserting into MySQL.

Kind Regards

Tom