Creating users and roles in MongoDB - Visual Walkthrough

Concept Flow - Creating users and roles

Start

↓

Define Role

↓

Create Role with Privileges

↓

Define User

↓

Create User with Roles

↓

User Can Access Resources

↓

End

First, define roles with specific permissions, then create users and assign these roles to control access.

Execution Sample

MongoDB

db.createRole({
  role: "readWriteReports",
  privileges: [{ resource: { db: "reports", collection: "" }, actions: ["find", "insert"] }],
  roles: []
});

db.createUser({
  user: "reportUser",
  pwd: "password123",
  roles: ["readWriteReports"]
});

This code creates a role with read and write access to the 'reports' database, then creates a user assigned to that role.

Execution Table

Step	Action	Input	Result	Notes
1	Define Role	{ role: "readWriteReports", privileges: [{ resource: { db: "reports", collection: "" }, actions: ["find", "insert"] }], roles: [] }	Role 'readWriteReports' created	Role has find and insert privileges on 'reports' DB
2	Create User	{ user: "reportUser", pwd: "password123", roles: ["readWriteReports"] }	User 'reportUser' created with role 'readWriteReports'	User can perform find and insert on 'reports' DB
3	User Access	User 'reportUser' tries to insert document in 'reports' collection	Success	User has insert privilege via role
4	User Access	User 'reportUser' tries to delete document in 'reports' collection	Failure	Delete not allowed by role privileges
5	End	-	-	Execution stops after user creation and role assignment

💡 User creation and role assignment complete; user permissions enforced by assigned role

Variable Tracker

Variable	Start	After Step 1	After Step 2	Final
role	undefined	{ name: "readWriteReports", privileges: [find, insert], roles: [] }	{ name: "readWriteReports", privileges: [find, insert], roles: [] }	{ name: "readWriteReports", privileges: [find, insert], roles: [] }
user	undefined	undefined	{ name: "reportUser", pwd: "password123", roles: ["readWriteReports"] }	{ name: "reportUser", pwd: "password123", roles: ["readWriteReports"] }

Key Moments - 3 Insights

Why can't the user delete documents even though they can insert and find?

Because the role 'readWriteReports' only includes 'find' and 'insert' actions, not 'delete'. See execution_table row 4 where delete fails.

Can a role include other roles?

Yes, roles can inherit privileges from other roles by listing them in the 'roles' array. Here, the role has an empty 'roles' array (execution_table row 1).

What happens if you create a user without assigning any roles?

The user will have no permissions and cannot access any database resources. This is not shown here but is important to remember.

Visual Quiz - 3 Questions

Look at the execution_table at step 3. What action does the user 'reportUser' successfully perform?

A Insert a document in 'reports' collection

B Delete a document in 'reports' collection

C Update a document in 'reports' collection

D Drop the 'reports' database

💡 Hint

Check the 'Result' column at step 3 in the execution_table.

At which step does the role 'readWriteReports' get created?

A Step 2

B Step 3

C Step 1

D Step 4

💡 Hint

Look at the 'Action' column in the execution_table for role creation.

If the role included 'delete' in privileges, what would change in the execution_table?

A Step 3 would fail

B Step 4 would show 'Success' for delete action

C User creation would fail

D Role creation would fail

💡 Hint

Refer to step 4 where delete currently fails due to missing privilege.

Concept Snapshot

Creating users and roles in MongoDB:
- Use db.createRole() to define roles with specific privileges.
- Privileges specify actions allowed on resources (databases/collections).
- Use db.createUser() to create users and assign roles.
- Users inherit permissions from assigned roles.
- Roles can include other roles for privilege inheritance.

Full Transcript

In MongoDB, you first create roles that define what actions are allowed on which databases or collections. For example, a role can allow reading and inserting documents in a specific database. Then, you create users and assign these roles to them. The user can then perform only the actions allowed by their roles. The execution table shows step-by-step how a role is created, then a user is created with that role, and how the user can perform allowed actions but not disallowed ones. Variables track the role and user objects as they are created. Key moments clarify common confusions like why a user cannot delete documents if the role does not allow it. The quiz tests understanding of these steps and permissions.