improve help for group()



3 files changed, 7 insertions, 3 deletions

diff --git a/db/dbcommands.cpp b/db/dbcommands.cpp
index f7e39afc2d4..57bc170d0f8 100644
--- a/db/dbcommands.cpp
+++ b/db/dbcommands.cpp
@@ -1111,7 +1111,7 @@ namespace mongo {
         GroupCommand() : Command("group"){}
         virtual bool slaveOk() { return true; }
         virtual void help( stringstream &help ) const {
-            help << "example: TODO";
+            help << "see http://www.mongodb.org/display/DOCS/Aggregation";
         }
 
         BSONObj getKey( const BSONObj& obj , const BSONObj& keyPattern , const string keyFunction , double avgSize ){
@@ -1182,6 +1182,7 @@ namespace mongo {
         bool run(const char *dbname, BSONObj& jsobj, string& errmsg, BSONObjBuilder& result, bool fromRepl ){
             static DBDirectClient db;
 
+            /* db.$cmd.findOne( { group : <p> } ) */
             const BSONObj& p = jsobj.firstElement().embeddedObjectUserCheck();
             
             BSONObj q;
@@ -1213,7 +1214,10 @@ namespace mongo {
             else if ( p["$keyf"].type() ){
                 keyf = p["$keyf"].ascode();
             }
-
+            else { 
+                errmsg = "parameter 'key' is missing or not an object";
+                return false;
+            }
 
             return group( realdbname , cursor , key , keyf , p["$reduce"].ascode() , p["initial"].embeddedObjectUserCheck() , errmsg , result );
         }
diff --git a/shell/collection.js b/shell/collection.js
index e2103e4abc5..32fbc519acf 100644
--- a/shell/collection.js
+++ b/shell/collection.js
@@ -36,6 +36,7 @@ DBCollection.prototype.help = function(){
     print("\tdb.foo.find(...).skip(n)");
     print("\tdb.foo.find(...).count()");
     print("\tdb.foo.count()");
+    print("\tdb.foo.group( { key : ..., initial: ..., reduce : ...[, cond: ...] } )");
     print("\tdb.foo.save(obj)");
     print("\tdb.foo.update(query, object[, upsert_bool])");
     print("\tdb.foo.ensureIndex(keypattern)");
diff --git a/shell/db.js b/shell/db.js
index 7cd7effddc9..0aa80cdaf34 100644
--- a/shell/db.js
+++ b/shell/db.js
@@ -261,7 +261,6 @@ DB.prototype.help = function() {
     print("\tdb.getPrevError()");
     print("\tdb.resetError()");
     print("\tdb.getCollectionNames()");
-    print("\tdb.group(ns, key[, keyf], cond, reduce, initial)");
     print("\tdb.currentOp() displays the current operation in the db" );
     print("\tdb.killOp() kills the current operation in the db" );
     print("\tdb.version() current version of the server" );