diff --git a/source/tutorial/model-tree-structures-with-ancestors-array.txt b/source/tutorial/model-tree-structures-with-ancestors-array.txt
index 69860699077..1b7c6283fe7 100644
--- a/source/tutorial/model-tree-structures-with-ancestors-array.txt
+++ b/source/tutorial/model-tree-structures-with-ancestors-array.txt
@@ -38,7 +38,7 @@ reference to the immediate parent category in the ``parent`` field:
 .. code-block:: javascript
 
    db.categories.insert( { _id: "MongoDB", ancestors: [ "Books", "Programming", "Databases" ], parent: "Databases" } )
-   db.categories.insert( { _id: "Postgres", ancestors: [ "Books", "Programming", "Databases" ], parent: "Databases" } )
+   db.categories.insert( { _id: "dbm", ancestors: [ "Books", "Programming", "Databases" ], parent: "Databases" } )
    db.categories.insert( { _id: "Databases", ancestors: [ "Books", "Programming" ], parent: "Programming" } )
    db.categories.insert( { _id: "Languages", ancestors: [ "Books", "Programming" ], parent: "Programming" } )
    db.categories.insert( { _id: "Programming", ancestors: [ "Books" ], parent: "Books" } )
diff --git a/source/tutorial/model-tree-structures-with-child-references.txt b/source/tutorial/model-tree-structures-with-child-references.txt
index a487c068847..771ce2749d2 100644
--- a/source/tutorial/model-tree-structures-with-child-references.txt
+++ b/source/tutorial/model-tree-structures-with-child-references.txt
@@ -36,8 +36,8 @@ the reference to the node's children in the field ``children``:
 .. code-block:: javascript
 
    db.categories.insert( { _id: "MongoDB", children: [] } )
-   db.categories.insert( { _id: "Postgres", children: [] } )
-   db.categories.insert( { _id: "Databases", children: [ "MongoDB", "Postgres" ] } )
+   db.categories.insert( { _id: "dbm", children: [] } )
+   db.categories.insert( { _id: "Databases", children: [ "MongoDB", "dbm" ] } )
    db.categories.insert( { _id: "Languages", children: [] } )
    db.categories.insert( { _id: "Programming", children: [ "Databases", "Languages" ] } )
    db.categories.insert( { _id: "Books", children: [ "Programming" ] } )
diff --git a/source/tutorial/model-tree-structures-with-materialized-paths.txt b/source/tutorial/model-tree-structures-with-materialized-paths.txt
index 20e4adf7e44..399c0520f4e 100644
--- a/source/tutorial/model-tree-structures-with-materialized-paths.txt
+++ b/source/tutorial/model-tree-structures-with-materialized-paths.txt
@@ -45,7 +45,7 @@ storing the path in the field ``path``; the path string uses the comma
    db.categories.insert( { _id: "Databases", path: ",Books,Programming," } )
    db.categories.insert( { _id: "Languages", path: ",Books,Programming," } )
    db.categories.insert( { _id: "MongoDB", path: ",Books,Programming,Databases," } )
-   db.categories.insert( { _id: "Postgres", path: ",Books,Programming,Databases," } )
+   db.categories.insert( { _id: "dbm", path: ",Books,Programming,Databases," } )
 
 - You can query to retrieve the whole tree, sorting by the field
   ``path``:
diff --git a/source/tutorial/model-tree-structures-with-nested-sets.txt b/source/tutorial/model-tree-structures-with-nested-sets.txt
index 152646bbace..4750e6cc2c3 100644
--- a/source/tutorial/model-tree-structures-with-nested-sets.txt
+++ b/source/tutorial/model-tree-structures-with-nested-sets.txt
@@ -43,7 +43,7 @@ The following example models the tree using *Nested Sets*:
    db.categories.insert( { _id: "Languages", parent: "Programming", left: 3, right: 4 } )
    db.categories.insert( { _id: "Databases", parent: "Programming", left: 5, right: 10 } )
    db.categories.insert( { _id: "MongoDB", parent: "Databases", left: 6, right: 7 } )
-   db.categories.insert( { _id: "Postgres", parent: "Databases", left: 8, right: 9 } )
+   db.categories.insert( { _id: "dbm", parent: "Databases", left: 8, right: 9 } )
 
 You can query to retrieve the descendants of a node: