Return field metadata on result object

Closes #209
Native implementation requires significant refactor and so I wont work on this
if/until there is an issue for it

lib/query.js

@@ -63,6 +63,7 @@ Query.prototype.handleRowDescription = function(msg) {
     var format = field.format;
     this._fieldNames[i] = field.name;
     this._fieldConverters[i] = Types.getTypeParser(field.dataTypeID, format);
+    this._result.addField(field);
   }
 };
 

lib/result.js

@@ -6,6 +6,7 @@ var Result = function() {
   this.rowCount = null;
   this.oid = null;
   this.rows = [];
+  this.fields = [];
 };
 
 var matchRegexp = /([A-Za-z]+) ?(\d+ )?(\d+)?/;
@@ -37,4 +38,9 @@ Result.prototype.addRow = function(row) {
   this.rows.push(row);
 };
 
+//Add a field definition to the result
+Result.prototype.addField = function(field) {
+  this.fields.push(field);
+};
+
 module.exports = Result;

test/integration/client/no-row-result-tests.js

@@ -0,0 +1,23 @@
+var helper = require(__dirname + '/test-helper');
+var pg = helper.pg;
+var config = helper.config;
+
+test('can access results when no rows are returned', function() {
+  if(config.native) return false;
+  var checkResult = function(result) {
+    assert(result.fields, 'should have fields definition');
+    assert.equal(result.fields.length, 1);
+    assert.equal(result.fields[0].name, 'val');
+    assert.equal(result.fields[0].dataTypeID, 25);
+    pg.end();
+  };
+
+  pg.connect(config, assert.success(function(client, done) {
+    var query = client.query('select $1::text as val limit 0', ['hi'], assert.success(function(result) {
+      checkResult(result);
+      done();
+    }));
+
+    assert.emits(query, 'end', checkResult);
+  }));
+});