Make a pair of columns unique together.
SQLite: A composite primary key permits repeated individual values while forbidding a duplicate combination.
CREATE TABLE memberships (person_id INTEGER,team_id INTEGER,PRIMARY KEY(person_id,team_id));
INSERT INTO memberships VALUES (1,10),(1,20);
SELECT person_id,team_id FROM memberships ORDER BY team_id;Expected output EXAMPLE
1|10 1|20
Details
Requires SQLite 3.40 or later. Run with sqlite3 demo.db in a scratch directory. Result rows below use | between columns, without headers; client display formatting may differ. A composite primary key permits repeated individual values while forbidding a duplicate combination. The CREATE and INSERT statements provide all input data. Run the complete example in a fresh scratch database or schema.
Tested on Ubuntu 24.04.5 LTS · · SQLite 3.45.1 · bash 5.2.21-2ubuntu4; coreutils 9.4-3ubuntu6.3
Test inputs, results and environment
The exact published code ran in a dedicated Linux test container with prepared inputs. Snippet process uid 65534 with a read-only root filesystem and temporary working files. Networking disabled. Fixtures and output records are isolated from the application database. Testing covers this example and its stated checks, not every input, operating system, or runtime version. The Linux container shares its host's kernel; this is not a native Windows test.
- Architecture / host kernel
- x86_64 / 6.18.54.1-microsoft-standard-WSL2
- Snippet identity / locale
- uid=65534, gid=65534 (unprivileged process) / C.UTF-8
- Interpreter invocation
Execute the exact SQL in a fresh database/schema; serialize result rows with | separators- Container image ID
sha256:ec91410a8f6ec3e985830b5e3a0560306d36f8c1c5ccd91a6699abe707123fa3- Code SHA-256
27c035e1a032a3d46b8cebc333363a48d49fee61d3727ee7471b80f8cf80f9c3- Dependencies
- bash 5.2.21-2ubuntu4; coreutils 9.4-3ubuntu6.3
Test input setup
These are the prepared inputs used by the test harness. See Details above for the prerequisites and how to run this example.
# No input files required.
Observed standard output
1|10 1|20
Exit code: 0. Standard error: empty. Validation: Exact stdout comparison. System-dependent values above are one recorded run.
Additional assertions that passed
Checks recorded by the test harness. Where Python assertions are shown, browser cases use Playwright and simulator cases may inspect pin transitions: result.stdout is captured output, work is the temporary directory, and Path is pathlib.Path. The harness also imports json and csv.
Every tested engine rejected this invalid write with an integrity/constraint error: INSERT INTO memberships VALUES (1,10);