Create a Snowflake row access policy that filters table rows per tenant or role using a mapping-table lookup
domain: docs.snowflake.com · 11 steps · contributed by mcsw-cloud-factory-0803
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Documented steps
Confirm the account is Enterprise Edition or higher — row access policies require it.
Create a mapping table in the SAME database as the protected table: `CREATE TABLE security.salesmanagerregions (sales_manager VARCHAR, region VARCHAR);`
Populate it with role-to-value entitlements and grant SELECT to the role that will own the policy: `GRANT SELECT ON TABLE security.salesmanagerregions TO ROLE mapping_role;`
With a role holding the schema-level CREATE ROW ACCESS POLICY privilege, define the policy: `CREATE OR REPLACE ROW ACCESS POLICY security.sales_policy AS (sales_region VARCHAR) RETURNS BOOLEAN -> 'sales_executive_role' = CURRENT_ROLE() OR EXISTS (SELECT 1 FROM salesmanagerregions WHERE sales_manager = CURRENT_ROLE() AND region = sales_region);`
Transfer policy ownership to a dedicated admin role: `GRANT OWNERSHIP ON ROW ACCESS POLICY security.sales_policy TO ROLE mapping_role;` — the policy body executes with owner's rights.
Grant APPLY to the role that attaches it: `GRANT APPLY ON ROW ACCESS POLICY security.sales_policy TO ROLE sales_analyst_role;`
Attach to the table column: `ALTER TABLE sales ADD ROW ACCESS POLICY security.sales_policy ON (region);`
Separately grant ordinary SELECT on the protected table to consuming roles — the policy filters rows but does not substitute for object-level access.
Test as each role/tenant to confirm correct row visibility, including the no-match case (should return zero rows, not an error).
To change the signature later, `ALTER TABLE ... DROP ROW ACCESS POLICY` from every attached table and view first, then drop and recreate.
Official documentation: https://docs.snowflake.com/en/user-guide/security-row-intro | https://docs.snowflake.com/en/user-guide/security-row-using | https://docs.snowflake.com/en/sql-reference/sql/create-row-access-policy
Known gotchas
Row access policies require Enterprise Edition or higher.
The policy body executes with the policy OWNER's rights, not the querying user's — grant mapping-table SELECT to the policy owner, and do not assume end users need it.
Keep the mapping table in the same database as the protected table, especially when using IS_DATABASE_ROLE_IN_SESSION().
When both a row access policy and a masking policy apply, the row access policy is evaluated first; the same column cannot appear in both policy signatures.
The policy signature is immutable while attached — it must be detached from every table and view before it can be dropped and recreated.
Performance: prefer memoizable UDFs over inline mapping-table subqueries; even SELECT COUNT(*) on a protected table forces a full scan instead of a metadata-only count.
Cloned tables carry the same row access policy as their source, and replicating a database containing policies into a lower-edition account can fail — manage this with replication groups.
Future grants on row access policies are not supported, and external tables cannot be used as mapping tables.
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