DOCS-602 adding link target and tweaking a sentence

Author: Sam Kleinman

source/faq/fundamentals.txt

@@ -125,15 +125,7 @@ files lazily. MongoDB may wait to write data to the data files for as
 much as one minute. This does not affect durability, as the journal
 has enough information to ensure crash recovery.
 
-Does MongoDB handle caching?
-----------------------------
-
-Yes. MongoDB keeps all of the most recently used data in RAM. If you
-have created indexes for your queries and your working data set fits
-in RAM, MongoDB serves all queries from memory.
-
-MongoDB does not implement a query cache: MongoDB serves all queries
-directly from the indexes and/or data files.
+.. _faq-database-and-caching:
 
 Does MongoDB require a separate caching layer for application-level caching?
 ----------------------------------------------------------------------------
@@ -147,8 +139,20 @@ need for a separate caching layer in the application.
 This differs from relational databases, where caching data is more
 expensive. Relational databases must transform data into object
 representations that applications can read and must store the
-transformed data in a separate cache. If joins are required that adds to
-the overhead.
+transformed data in a separate cache: if these transformation from
+data to application objects require joins, this process increases the
+overhead related to using the database which increases the importance
+of the caching layer.
+
+Does MongoDB handle caching?
+----------------------------
+
+Yes. MongoDB keeps all of the most recently used data in RAM. If you
+have created indexes for your queries and your working data set fits
+in RAM, MongoDB serves all queries from memory.
+
+MongoDB does not implement a query cache: MongoDB serves all queries
+directly from the indexes and/or data files.
 
 What language is MongoDB written in?
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