Add parser support for ON DELETE and ON UPDATE CASCADE in REFERENCES

[Copilot]

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Description

This PR adds parser support for ON DELETE and ON UPDATE referential actions in FOREIGN KEY constraints, fixing issue #897.

The parser previously threw an error "Expecting 'UPDATE', got 'DELETE'" when encountering ON DELETE CASCADE syntax in REFERENCES clauses. This has been resolved by implementing comprehensive support for all standard SQL referential actions.

Note: AlaSQL currently parses but does not enforce CASCADE behavior. This means that while the syntax is now accepted for SQL-99 compatibility, deleting parent rows will not automatically delete or update child rows. The implementation provides syntax compatibility without behavioral enforcement.

Changes Made

Parser Modifications (src/alasqlparser.jison)

1. Added lexer tokens: CASCADE and RESTRICT are now recognized keywords
2. New grammar rules:
   • ReferentialAction: Handles CASCADE, SET NULL, SET DEFAULT, RESTRICT, NO ACTION
   • OnDeleteClause: Handles ON DELETE <action>
   • OnUpdateClause: Handles ON UPDATE <action>
   • OnReferentialActions: Combines ON DELETE and ON UPDATE in any order or individually
3. Updated REFERENCES syntax: Both column-level and table-level FOREIGN KEY constraints now accept optional ON DELETE and ON UPDATE clauses
4. Flexible ordering: ON DELETE and ON UPDATE can appear in any order

Test Coverage (test/test897.js)

Created comprehensive test suite with 20 tests covering:

• All five SQL-99 referential actions: CASCADE, SET NULL, SET DEFAULT, RESTRICT, NO ACTION
• ON DELETE CASCADE, ON UPDATE CASCADE, and ON DELETE/UPDATE NO ACTION
• Both ON DELETE and ON UPDATE together (in either order)
• Column-level REFERENCES syntax
• Table-level FOREIGN KEY syntax
• FOREIGN KEY with CONSTRAINT names
• Multiple foreign keys in one table with different actions
• Composite keys with referential actions
• Backward compatibility (REFERENCES and FOREIGN KEY without ON DELETE/UPDATE clauses)
• Comprehensive data validation: Each test:
  • Creates parent and child tables with CASCADE syntax using multiline SQL template literals
  • Inserts multiple rows of data into both tables
  • Executes SELECT queries to retrieve and verify complete data sets
  • Uses assert.deepEqual() to validate entire result objects against expected values
  • Demonstrates real-world scenarios with actual data operations

Supported Syntax

The parser now correctly handles all these patterns:

-- Column-level REFERENCES
REFERENCES table(column) ON DELETE CASCADE
REFERENCES table(column) ON UPDATE CASCADE
REFERENCES table(column) ON DELETE CASCADE ON UPDATE SET NULL
REFERENCES table(column) ON UPDATE CASCADE ON DELETE RESTRICT

-- Table-level FOREIGN KEY
FOREIGN KEY (column) REFERENCES table(column) ON DELETE CASCADE
FOREIGN KEY (column) REFERENCES table(column) ON UPDATE NO ACTION
FOREIGN KEY (column) REFERENCES table(column) ON DELETE SET NULL ON UPDATE CASCADE
CONSTRAINT name FOREIGN KEY (column) REFERENCES table(column) ON DELETE CASCADE

Testing

• ✅ All 20 new tests pass
• ✅ All existing tests pass (backward compatibility maintained)
• ✅ Existing FOREIGN KEY tests (test048) still pass
• ✅ Tests use assert.deepEqual() for comprehensive validation of complete result sets
• ✅ Tests demonstrate real-world scenarios with actual data operations (CREATE, INSERT, SELECT)
• ✅ Multiline SQL with template literals improves code readability
• ✅ Backward compatible - ON DELETE/UPDATE clauses are optional
• ✅ SQL-99 compliant - all standard referential actions supported
• ✅ Code formatting validated with Prettier
• ✅ Build process completes successfully

The changes maintain full SQL-99 syntax compliance for referential integrity while preserving complete backward compatibility with existing code.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>CASCADE not supported (sqlite) </issue_title>
<issue_description>I've following table in sqlite [TEMP_COMMODITY_UUIDS]:

CREATE TABLE TEMP_COMMODITY_UUIDS (
    ID           INTEGER NOT NULL
                         PRIMARY KEY AUTOINCREMENT
                         REFERENCES COMMODITY (ID) ON DELETE CASCADE,
    UUID         TEXT    NOT NULL,
    BACKEND_UUID TEXT
);

When I try to execute in browser:

alasql([
'ATTACH SQLITE DATABASE db("test.dat");
USE db;
select * from TEMP_COMMODITY_UUIDS'
]).then(function(res){
     console.log("test:",res.pop());
});

I got:

> Uncaught SyntaxError: Parse error on line 1:
...ES COMMODITY(ID) ON DELETE CASCADE, [UUI
-----------------------^
Expecting 'UPDATE', got 'DELETE'
    at Parser.parser.parseError (alasql.js:2210)
    at Parser.parse (alasql.js:2084)
    at Function.alasql.parse (alasql.js:4396)
    at alasql.js:17141
    at Array.forEach (<anonymous>)
    at alasql.js:17138

It seems, alasql.js (0.4.0) can't understand 'ON DELETE CASCADE' construction of sqlite.
Similar query, using sql.js directly work just right.

Thanks.</issue_description>

Comments on the Issue (you are @copilot in this section)

@mathiasrw Great input! thanks for taking the time to describe.

Handling CASCADE is not implemented at the moment. Ill set it as a feature request!</comment_new>
<comment_new>@mathiasrw
@ChristopherHButler We are happy to look at any pull request with this. I have not heard of any people working on this now.

• Fixes CASCADE not supported (sqlite)  #897

---

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[mathiasrw]

@copilot Plesae continye

[Copilot]

@copilot Plesae continye

Completed! Added support for ON DELETE and ON UPDATE CASCADE (and other referential actions: SET NULL, SET DEFAULT, RESTRICT, NO ACTION) for both column-level and table-level FOREIGN KEY constraints. The parser now correctly handles the syntax from the issue. All tests pass. Commit: 7302433

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[mathiasrw]

@copilot

[mathiasrw]

@copilot

Run yarn test-format-all
yarn run v1.22.22
$ prettier --list-different '{.,src,test}/*.{js,ts,json}' || (echo 'Please correct file formatting using yarn format-all and try again.' && exit 1)
test/test897.js
Please correct file formatting using yarn format-all and try again.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
Error: Process completed with exit code 1.

[mathiasrw]

@copilot continue

[Copilot]

@copilot continue

The work is complete. All formatting has been applied (test897.js is properly formatted), all 20 tests pass, and backward compatibility is maintained. The PR is ready for review. Latest commit: 466688f

[mathiasrw]

@copilot

Can you make a new issue describing what needs to be done to fix

AlaSQL currently parses but does not enforce CASCADE behavior (i.e., deleting parent rows won't cascade to children).

[Copilot]

@copilot

Can you make a new issue describing what needs to be done to fix
...

I don't have the ability to create new GitHub issues directly. However, I can provide the content for a new issue that describes what needs to be implemented:

Title: Implement CASCADE behavior enforcement for FOREIGN KEY constraints

Description:
Currently, AlaSQL parses CASCADE syntax but does not enforce the behavior. When a parent row is deleted or updated, child rows with ON DELETE CASCADE or ON UPDATE CASCADE are not automatically affected.

What needs to be implemented:

1. ON DELETE CASCADE: When a row in the parent table is deleted, automatically delete all rows in child tables that reference it
2. ON DELETE SET NULL: Set foreign key columns to NULL in child tables when parent is deleted
3. ON DELETE SET DEFAULT: Set foreign key columns to their default value when parent is deleted
4. ON DELETE RESTRICT: Prevent deletion of parent row if child rows exist
5. ON UPDATE CASCADE: When parent key is updated, update matching foreign keys in child tables
6. ON UPDATE SET NULL: Set foreign key to NULL when parent key is updated
7. ON UPDATE SET DEFAULT: Set foreign key to default when parent key is updated
8. ON UPDATE RESTRICT: Prevent update of parent key if child rows exist

Implementation areas:

• Modify DELETE statement handler (src/74delete.js) to check for child tables and apply CASCADE actions
• Modify UPDATE statement handler (src/74update.js) to check for child tables and apply CASCADE actions
• Store foreign key metadata including ondelete/onupdate actions in table definition
• Add validation for RESTRICT actions before allowing delete/update

Related: PR #[current PR number], Issue #897