diff --git a/doc/backend/DataModel.md b/doc/backend/DataModel.md
index 417a712..e3dbe15 100644
--- a/doc/backend/DataModel.md
+++ b/doc/backend/DataModel.md
@@ -27,7 +27,14 @@ In order to understand the datamodel of the CodeGrader a little bit faster you c
 (17 rows)
 ```
 
+In general all tables will include 3 metadata columns. 
+- id: Primary Key of the table and auto generated by the database
+- creation_dts: DateTime stamp of the database when the object has last been created. 
+- updated_dts: DateTime stamp of the database when te object has last been updated. 
+
+
 ## Admin Type
+The admin type specifies the rights that an admin has within the admin frontend.
 ```
                                         Table "public.admin_type"
     Column    |           Type           | Collation | Nullable |                Default
@@ -47,6 +54,7 @@ Referenced by:
 ```
 
 ## Admin User
+Stores the user Object of an Administrator User for the admin frontend. 
 ```
                                         Table "public.adminuser"
     Column    |           Type           | Collation | Nullable |                Default
@@ -75,6 +83,7 @@ Foreign-key constraints:
 ```
 
 ## Attachment
+Table to store the properties of a file stored in the file table for additional files of a task. 
 ```
                                         Table "public.attachment"
     Column    |           Type           | Collation | Nullable |                Default
@@ -96,6 +105,7 @@ Foreign-key constraints:
 ```
 
 ## Evaluation Type
+The type of evaluation entities used for the evaluation of a task. 
 ```
                                         Table "public.evaluation_type"
     Column    |           Type           | Collation | Nullable |                   Default
@@ -113,6 +123,7 @@ Indexes:
 ```
 
 ## Evaluation Result
+The result of an evaluation. One entry per Submission. 
 ```
                                           Table "public.evaluationresult"
       Column      |           Type           | Collation | Nullable |                   Default
@@ -132,6 +143,7 @@ Foreign-key constraints:
 ```
 
 ## Execution Result
+The output of an execution for one testcase of an Submission. 
 ```
                                            Table "public.executionresult"
        Column        |           Type           | Collation | Nullable |                   Default
@@ -158,6 +170,7 @@ Foreign-key constraints:
 ```
 
 ## Exercise
+Exercise is a logical Grouping for multiple Tasks with some additional informations. 
 ```
                                         Table "public.exercise"
     Column    |           Type           | Collation | Nullable |               Default
@@ -181,6 +194,7 @@ Referenced by:
 ```
 
 ## File
+Table to store Binary Data in a database. 
 ```
                                         Table "public.file"
     Column     |           Type           | Collation | Nullable |             Default
@@ -205,6 +219,7 @@ Referenced by:
 ```
 
 ## Instruction
+The Instructions of how to solve the task. This is a file with the file stored in the file table. 
 ```
                                         Table "public.instruction"
     Column    |           Type           | Collation | Nullable |                 Default
@@ -226,6 +241,7 @@ Foreign-key constraints:
 ```
 
 ## Membership
+Membership shows which user can access which subject. In other words: which tasks, exercises and more he will be able to access. 
 ```
                                         Table "public.membership"
     Column    |           Type           | Collation | Nullable |                Default
@@ -248,6 +264,8 @@ Foreign-key constraints:
 ```
 
 ## Profile
+The profile is a logical grouping of users and other objects. This is also the grouping used for the implemetation of the
+multi-client-capability. 
 ```
                                         Table "public.profile"
     Column    |           Type           | Collation | Nullable |               Default
@@ -269,6 +287,7 @@ Referenced by:
 ```
 
 ## Subject
+the logical grouping of multiple exercises into a subject. Can also be looked as a Course in School. 
 ```
                                         Table "public.subject"
     Column    |           Type           | Collation | Nullable |               Default
@@ -293,6 +312,8 @@ Referenced by:
 ```
 
 ## Submission
+A submission made by a user for a specific task. The user did a submission for a given task. 
+This submission will be evaluated in the execution service and following.  
 ```
                                         Table "public.submission"
     Column    |           Type           | Collation | Nullable |                Default
@@ -319,6 +340,7 @@ Referenced by:
 ```
 
 ## Task
+The Task is the entity of a Coding Challenge which has files attached to it such as Instructions, Attachments and more.
 ```
                                         Table "public.task"
     Column    |           Type           | Collation | Nullable |             Default
@@ -346,6 +368,8 @@ Referenced by:
 ```
 
 ## Testcase
+A Testcase is the definition of a input and correct output. The input will be used in the execution service while the
+ouput is used in the evaluation service. 
 ```
                                         Table "public.testcase"
     Column    |           Type           | Collation | Nullable |               Default
@@ -371,6 +395,7 @@ Referenced by:
 ```
 
 ## Token
+The Token is used for authentication of the frontend to the backend api. (Bearer Token)
 ```
                                         Table "public.token"
     Column    |           Type           | Collation | Nullable |              Default
@@ -388,6 +413,7 @@ Indexes:
 ```
 
 ## User
+A User for the user frontend of the codegrader with login data. 
 ```
                                         Table "public.user"
     Column    |           Type           | Collation | Nullable |             Default