diff --git a/README.md b/README.md
index 3f81b83..61aa82d 100644
--- a/README.md
+++ b/README.md
@@ -40,7 +40,7 @@ _La dernière version à jour de ce document est disponible sur [github](https:/
 - [Code source publié sur _Github_][4]
 - [Tableau agile][5]
 - [Modèle physique de données][6]
-- [Script de création de votre base de données][7]
+- Script de création de votre base de données
 - [Document texte expliquant la démarche][8]
     * difficultés rencontrées / solutions trouvées
     * lien _Github_
@@ -53,7 +53,7 @@ _La dernière version à jour de ce document est disponible sur [github](https:/
 [3]: https://fr.openfoodfacts.org/
 [4]: https://github.com/freezed/ocp5/blob/master/README.md
 [5]: https://github.com/freezed/ocp5/projects/1
-[6]: https://github.com/freezed/ocp5/blob/master/mpd.png
+[6]: https://github.com/freezed/ocp5/blob/master/doc/pdm.png
 [7]: https://github.com/freezed/ocp5/blob/master/create-db.sql
-[8]: https://github.com/freezed/ocp5/blob/master/approach.md
-[9]: https://github.com/freezed/ocp5/blob/master/documentation.md#documentation "Project documentation"
+[8]: https://github.com/freezed/ocp5/blob/master/doc/approach.md
+[9]: https://github.com/freezed/ocp5/blob/master/doc/documentation.md#documentation "Project documentation"
diff --git a/approach.md b/doc/approach.md
similarity index 100%
rename from approach.md
rename to doc/approach.md
diff --git a/documentation.md b/doc/documentation.md
similarity index 86%
rename from documentation.md
rename to doc/documentation.md
index 21e5898..fb9d3b1 100644
--- a/documentation.md
+++ b/doc/documentation.md
@@ -4,32 +4,28 @@ Documentation
 ## Created with
 
 - `python 3.6.4 `
-- ~`Requests`~ [`TODO #4`][4]
+- `Requests`
 - ~`PyMySQL` or `openfoodfacts-python`~ [`TODO #4`][4]
 
 ## Installation
 
 1. get the code : `git clone git@github.com:freezed/ocp5.git`
-2. create a dedicated virtualenv : `python3.7 -m venv .venv; source .venv/bin/activate`
-3. ~adds dependencies : `cd ocp5; pip install -r requirement.txt`~ [TODO #4][4]
+2. create a dedicated virtualenv : `python3 -m venv .venv; source .venv/bin/activate`
+3. adds dependencies : `cd ocp5; pip install -r requirements.txt`
 
 ## Collects data
 
 1. [OpenFoodFacts data uses more than 170 fields][92]. Here are those we keep localy :
 ```
 code
-url
-last_modified_t
 product_name
 categories_fr
-purchase_places
-stores
 nutrition-score-fr_100g
 ```
 2. Request will only ask for tagged products with `'countries':'france'`
-3. ~Physical Data Model~ [`TODO #2`][2]
+3. Physical Data Model
 
-![-Physical Data Model-][2]
+![-Physical Data Model-][96]
 
 4. ~Creates local MariaDB/MySQL : `./create-db.py`~ [`TODO #2`][2]
 
diff --git a/doc/pdm.png b/doc/pdm.png
new file mode 100644
index 0000000..89dce07
Binary files /dev/null and b/doc/pdm.png differ
diff --git a/doc/pdm.puml b/doc/pdm.puml
new file mode 100644
index 0000000..706708f
--- /dev/null
+++ b/doc/pdm.puml
@@ -0,0 +1,55 @@
+@startuml
+
+title Physical data model\n
+
+/' = = = = = = = STYLE = = = = = = = '/
+hide empty methods
+hide circle
+skinparam linetype ortho
+skinparam class {
+    BackgroundColor<<assoc>> lightblue
+}
+
+/' = = = = = = = MACRO = = = = = = = '/
+!define rel(a,b,c,d,e) a c e
+!define pyk(n,t="MEDIUMINT NOT NULL UNSIGNED") <font color="red">PK:<b>n</b> <size:09>[t]</size></font>
+!define fnk(n,r,t="MEDIUMINT NOT NULL UNSIGNED") <font color="blue">FK:<b>n</b> <size:09>[t]</size></font>
+!define pfk(n,r,t="MEDIUMINT NOT NULL UNSIGNED") <font color="orangered">PFK:<b>n</b> <size:09>[t]</size></font>
+!define att(n,u,s) {field} <b>n</b> [s]
+
+/' = = = = = = = CLASSE = = = = = = = '/
+class product
+class category
+class prod_category <<assoc>>
+
+/' = = = = = = = RELATION = = = = = = = '/
+rel(product,1..,--,1..*,category)
+
+/' = = = = = = = KEY = = = = = = = '/
+class product {
+    pyk(id)
+    ..
+}
+class category {
+    pyk(id)
+    ..
+}
+class prod_category <<assoc>> {
+    pfk(category_id,category.id)
+    pfk(product_id,product.id)
+    ..
+}
+/' = = = = = = = ATTRIBUTE = = = = = = = '/
+class product {
+    att(name,String,VARCHAR(200))
+    att(nutrition_grades,String,VARCHAR(1))
+}
+class category {
+    att(name,String,VARCHAR(200))
+}
+
+/' = = = = = = = ASSOCIATION = = = = = = = '/
+rel(product,.,--,.,prod_category)
+rel(category,.,-,.,prod_category)
+
+@enduml