Fix bug with virtual tables in statemnts

Virtual tables can exist on a single statement and do not show up in the
db schema, so skip them when testing for rowid columns.

lib/amalgalite/statement.rb

@@ -347,7 +347,7 @@ def result_meta
           # only check for rowid if we have a table name and it is not one of the
           # sqlite_master tables.  We could get recursion in those cases.
           if not using_rowid_column? and tbl_name and
-             not %w[ sqlite_master sqlite_temp_master].include?( tbl_name ) and is_column_rowid?( tbl_name, col_name ) then
+             not %w[ sqlite_master sqlite_temp_master ].include?( tbl_name ) and is_column_rowid?( tbl_name, col_name ) then
             @rowid_index = idx
           end
 
@@ -363,7 +363,10 @@ def result_meta
     # is the column indicated by the Column a 'rowid' column
     #
     def is_column_rowid?( table_name, column_name )
-      column_schema  = @db.schema.tables[table_name].columns[column_name]
+      table_schema = @db.schema.tables[table_name]
+      return false unless table_schema
+
+      column_schema  = table_schema.columns[column_name]
       if column_schema then
         if column_schema.primary_key? and column_schema.declared_data_type and column_schema.declared_data_type.upcase == "INTEGER" then
           return true

spec/json_spec.rb

@@ -0,0 +1,15 @@
+require 'spec_helper'
+require 'amalgalite/sqlite3'
+require 'rbconfig'
+
+describe "Amalgalite handles the JSON extension" do
+  it "can parse a `json_each` call" do
+    db = Amalgalite::Database.new( ":memory:" )
+    values = %w[ a b c d e f g ]
+    db.execute("CREATE TABLE jtest(id, json)")
+    db.execute("INSERT INTO jtest(id, json) values (1, json($json))", { "$json" => values })
+    rows = db.execute("SELECT jtest.id as i, value as v FROM jtest, json_each(jtest.json)")
+
+    rows.size.should eq(values.size)
+  end
+end