Keep children while clearing a deleted relationship.
SQL Server: ON DELETE SET NULL requires a nullable foreign-key column.
CREATE TABLE parents (id INTEGER PRIMARY KEY);
CREATE TABLE children (id INTEGER PRIMARY KEY,parent_id INTEGER REFERENCES parents(id) ON DELETE SET NULL);
INSERT INTO parents VALUES (1);
INSERT INTO children VALUES (10,1);
DELETE FROM parents WHERE id=1;
SELECT id,parent_id FROM children;Expected output EXAMPLE
10|NULL
Details
Requires SQL Server 2022 or later. Run in an empty scratch database in SSMS or sqlcmd. Result rows below use | between columns, without headers; client display formatting may differ. ON DELETE SET NULL requires a nullable foreign-key column. The CREATE and INSERT statements provide all input data. Run the complete example in a fresh scratch database or schema.
SQLite connections must enable PRAGMA foreign_keys = ON before starting a transaction; the verification connection does so. PostgreSQL and SQL Server enforce these declared foreign keys directly.
Tested on Ubuntu 24.04.5 LTS · · SQL Server 16.0.4295.3 · bash 5.2.21-2ubuntu4; coreutils 9.4-3ubuntu6.3; psycopg 3.2.10; pymssql 2.3.8
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. Database services use a private internal Docker network without published ports. Fresh scratch schema/database for each case; test database administrator credentials are confined to these disposable services. 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
916379cbf013222ae76007af88cff4a9ed6d80541c1abc4464357a355fb9e0d4- Dependencies
- bash 5.2.21-2ubuntu4; coreutils 9.4-3ubuntu6.3; psycopg 3.2.10; pymssql 2.3.8
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.
SQLite connection: PRAGMA foreign_keys = ON before executing the published SQL.
Observed standard output
10|NULL
Exit code: 0. Standard error: empty. Validation: Exact stdout comparison. System-dependent values above are one recorded run.