Row Level Security
Row Level Security (RLS) is a feature in PostgreSQL that provides the ability to control which users can
DELETE which rows in a table. It adds an additional layer of security in multi-user database environments and is crucial for protecting sensitive data.
Understanding Row Level Security
RLS works by enabling you to define policies that restrict, on a per-user basis, whether certain rows can be returned by a
SELECT query or modified by an
DELETE query. This is particularly useful in multi-tenant environments where you want to ensure that users can only access their own data.
In PostgreSQL, RLS is disabled by default for all tables. To enable RLS, you use the
ALTER TABLE command with the ENABLE ROW LEVEL SECURITY clause. Once RLS is enabled, all users (except the table owner and superusers) are denied access to the table—unless a policy is explicitly added to grant them access.
Importance of Row Level Security
RLS is important for a variety of reasons:
Data Protection: RLS helps to protect sensitive data by ensuring that users can only access data that they are authorized to see. This is particularly important in industries such as healthcare or finance where regulations require strict controls over data access.
Multi-tenancy: In multi-tenant environments, RLS can be used to ensure that each tenant can only access their own data. This is much more efficient and secure than having separate tables or databases for each tenant.
Flexibility: RLS policies can be defined using any boolean SQL expression, which provides a great deal of flexibility. For example, you could define a policy that only allows users to access data that was created within the last 30 days.