Merge pull request #1674 from kibarda/devel

Documentation: a few titles added

Documentation/Books/Users/Aql/Invoke.mdpp

@@ -1,12 +1,17 @@
 !CHAPTER How to invoke AQL 
 
-!SECTION Executing queries
-
 You can run AQL queries from your application via the HTTP REST API. The full
 API description is available at [HTTP Interface for AQL Query Cursors](../HttpAqlQueryCursor/README.md).
 
-You can also run AQL queries from arangosh. To do so, you can use the *_query* method 
-of the *db* object. This will run the specified query in the context of the currently
+You can also run AQL queries from arangosh.
+
+!SECTION Executing queries from Arangosh 
+
+
+!SUBSECTION with db._query
+
+One can execute queries with the *_query* method of the *db* object. 
+This will run the specified query in the context of the currently
 selected database and return the query results in a cursor. The results of the cursor
 can be printed using its *toArray* method:
     
@@ -19,6 +24,8 @@ can be printed using its *toArray* method:
     @END_EXAMPLE_ARANGOSH_OUTPUT
     @endDocuBlock 01_workWithAQL_all
 
+!SUBSUBSECTION db._query Bind parameters
+
 To pass bind parameters into a query, they can be specified as second argument to the
 *_query* method:
 
@@ -32,6 +39,8 @@ To pass bind parameters into a query, they can be specified as second argument t
     @END_EXAMPLE_ARANGOSH_OUTPUT
     @endDocuBlock 02_workWithAQL_bindValues
 
+!SUBSUBSECTION ES6 template strings 
+
 It is also possible to use ES6 template strings for generating AQL queries. There is
 a template string generator function named *aqlQuery*:
 
@@ -59,6 +68,8 @@ Note: data-modification AQL queries normally do not return a result (unless the
 contains an extra *RETURN* statement). When not using a *RETURN* statement in the query, the 
 *toArray* method will return an empty array. 
 
+!SUBSUBSECTION Statistics
+ 
 It is always possible to retrieve statistics for a query with the *getExtra* method:
 
     @startDocuBlockInline 03_workWithAQL_getExtra
@@ -72,6 +83,8 @@ It is always possible to retrieve statistics for a query with the *getExtra* met
 
 The meaning of the statistics values is described in [Execution statistics](QueryStatistics.md).
 
+!SUBSECTION with _createStatement (ArangoStatement) 
+
 The *_query* method is a shorthand for creating an ArangoStatement object,
 executing it and iterating over the resulting cursor. If more control over the
 result set iteration is needed, it is recommended to first create an
@@ -93,8 +106,10 @@ To execute the query, use the *execute* method of the statement:
     @END_EXAMPLE_ARANGOSH_OUTPUT
     @endDocuBlock 05_workWithAQL_statements2
 
-This has executed the query. The query results are available in a cursor
-now. The cursor can return all its results at once using the *toArray* method.
+!SUBSUBSECTION Cursors
+
+Once the query executed the query results are available in a cursor. 
+The cursor can return all its results at once using the *toArray* method.
 This is a short-cut that you can use if you want to access the full result
 set without iterating over it yourself.
 
@@ -106,6 +121,8 @@ set without iterating over it yourself.
     @END_EXAMPLE_ARANGOSH_OUTPUT
     @endDocuBlock 05_workWithAQL_statements3
     
+
+
 Cursors can also be used to iterate over the result set document-by-document.
 To do so, use the *hasNext* and *next* methods of the cursor:
 
@@ -124,6 +141,8 @@ the results again, the query needs to be re-executed.
 Additionally, the iteration can be done in a forward-only fashion. There is no 
 backwards iteration or random access to elements in a cursor.    
 
+!SUBSUBSECTION ArangoStatement parameters binding
+
 To execute an AQL query using bind parameters, you need to create a statement first
 and then bind the parameters to it before execution:
 
@@ -175,6 +194,8 @@ making it a bit more convenient:
     } );
     @END_EXAMPLE_ARANGOSH_OUTPUT
     @endDocuBlock 05_workWithAQL_statements8
+
+!SUBSUBSECTION Counting with a cursor
     
 Cursors also optionally provide the total number of results. By default, they do not. 
 To make the server return the total number of results, you may set the *count* attribute to