每個使用者結合多個政策

RLS 在 Amazon Redshift 中，支援為每個使用者和物件連接多個政策。當為使用者定義多個政策時，Amazon Redshift 會根據資料表RLSCONJUNCTIONTYPE的設定，使用 AND或 OR 語法套用所有政策。如需結合類型的更多相關資訊，請參閱 ALTER TABLE。

資料表上的多個政策都可以與您建立關聯。您可以直接附加多個政策，或者您屬於多個角色，而這些角色附加了不同的政策。

當多個政策應該限制指定關係中的資料列存取時，您可以將RLSCONJUNCTIONTYPE關係設定為 AND。請考量下列範例。Alice 只能看到具有 的 "catname" NBA作為指定政策的運動事件。

-- Create an analyst role and grant it to a user named Alice.
CREATE ROLE analyst;
CREATE USER alice WITH PASSWORD 'Name_is_alice_1';
GRANT ROLE analyst TO alice;

-- Create an RLS policy that only lets the user see sports.
CREATE RLS POLICY policy_sports
WITH (catgroup VARCHAR(10))
USING (catgroup = 'Sports');

-- Create an RLS policy that only lets the user see NBA.
CREATE RLS POLICY policy_nba
WITH (catname VARCHAR(10))
USING (catname = 'NBA');

-- Attach both to the analyst role.
ATTACH RLS POLICY policy_sports ON category TO ROLE analyst;
ATTACH RLS POLICY policy_nba ON category TO ROLE analyst;

-- Activate RLS on the category table with AND CONJUNCTION TYPE. 
ALTER TABLE category ROW LEVEL SECURITY ON CONJUNCTION TYPE AND;

-- Change session to Alice.
SET SESSION AUTHORIZATION alice;

-- Select all from the category table.
SELECT catgroup, catname
FROM category;

 catgroup | catname 
---------+---------
 Sports   | NBA
(1 row)

當多個政策應允許使用者在指定關係中看到更多資料列時，使用者可以設定與 OR RLS CONJUNCTION TYPE 的關係。請考量下列範例。Alice 只能看到「音樂會」和「體育」做為指定政策。

-- Create an analyst role and grant it to a user named Alice.
CREATE ROLE analyst;
CREATE USER alice WITH PASSWORD 'Name_is_alice_1';
GRANT ROLE analyst TO alice;

-- Create an RLS policy that only lets the user see concerts.
CREATE RLS POLICY policy_concerts
WITH (catgroup VARCHAR(10))
USING (catgroup = 'Concerts');

-- Create an RLS policy that only lets the user see sports.
CREATE RLS POLICY policy_sports
WITH (catgroup VARCHAR(10))
USING (catgroup = 'Sports');

-- Attach both to the analyst role.
ATTACH RLS POLICY policy_concerts ON category TO ROLE analyst;
ATTACH RLS POLICY policy_sports ON category TO ROLE analyst;

-- Activate RLS on the category table with OR CONJUNCTION TYPE. 
ALTER TABLE category ROW LEVEL SECURITY ON CONJUNCTION TYPE OR;

-- Change session to Alice.
SET SESSION AUTHORIZATION alice;

-- Select all from the category table.
SELECT catgroup, count(*)
FROM category
GROUP BY catgroup ORDER BY catgroup;

 catgroup | count 
---------+-------
 Concerts |  3
 Sports   |  5
(2 rows)