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16 commits

Author SHA1 Message Date
Simon Willison
16bbfb582d add_foreign_keys() errors instead of silently dropping action changes
The existing-foreign-key dedup compared only columns and other_table, so
requesting an FK that already exists with different ON DELETE/ON UPDATE
actions was a silent no-op - and with add_foreign_key() raising "already
exists", there was no signal that the requested actions were dropped.
An exact match (including actions) is still skipped for idempotency;
a mismatch now raises AlterError pointing at table.transform().

Also validates that compound foreign keys passed as 4-tuples have the
same number of columns on both sides - extra other-columns were being
silently discarded, e.g. ("t", ("a",), "other", ("a", "b")) created a
single-column key referencing just "a".

Refs https://github.com/simonw/sqlite-utils/issues/769#issuecomment-4900034150

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-06 21:53:48 -07:00
Simon Willison
29ca9d27e2 foreign_keys= accepts mixed ForeignKey objects, tuples and strings again
resolve_foreign_keys() used all-or-nothing isinstance checks, so mixing
ForeignKey objects with tuples raised "foreign_keys= should be a list of
tuples" - a regression from 3.x, where ForeignKey was a namedtuple and
passed the tuple check. Each item is now normalized individually, which
also allows bare column-name strings in a mixed list.

Refs https://github.com/simonw/sqlite-utils/issues/769#issuecomment-4900034150

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-06 21:37:56 -07:00
Simon Willison
404e935b63 ForeignKey is now a frozen dataclass, restoring hashability
The namedtuple-to-dataclass change made ForeignKey unhashable, breaking
set(table.foreign_keys) and dict-key usage that worked in 3.x. frozen=True
restores immutability and hashability. Equality and hashing cover all
compared fields including on_delete/on_update - two foreign keys differing
only in their actions are different constraints.

Refs https://github.com/simonw/sqlite-utils/issues/769#issuecomment-4900034150

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-06 21:35:45 -07:00
Simon Willison
8e015d024c Compound primary keys now resolve in PRIMARY KEY declaration order
PRAGMA table_info sets is_pk to the 1-based position of each column
within the PRIMARY KEY, which can differ from table column order.
table.pks previously returned table column order, so an implicit
compound FOREIGN KEY ... REFERENCES other was introspected with its
referenced columns inverted, and transform() baked that inverted order
into the rewritten schema - failing with IntegrityError on valid data,
or silently reversing the constraint with foreign keys off.

table.pks, compound foreign key guessing (create, add_foreign_key) and
transform() now all use declaration order, and transform() no longer
reorders a compound PRIMARY KEY (b, a) into table column order.

Refs https://github.com/simonw/sqlite-utils/issues/769#issuecomment-4900034150

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-06 21:34:02 -07:00
Simon Willison
0ec0180405 add_foreign_key() on_delete= and on_update= parameters, closes #530
table.add_foreign_key() now accepts on_delete= and on_update= to
create foreign keys with ON DELETE/ON UPDATE actions:

    table.add_foreign_key("author_id", "authors", "id", on_delete="CASCADE")

Works for compound foreign keys too.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-05 15:49:20 -07:00
Simon Willison
658185d297 Fix compound foreign key test failure against sqlean
test_create_table_compound_foreign_key_enforced caught the stdlib
sqlite3.IntegrityError, but sqlean's IntegrityError is not a subclass
of it. Import sqlite3 from sqlite_utils.utils like the other test
modules, so the right exception is used whichever backend is installed.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-05 15:46:16 -07:00
Simon Willison
5b61530965 db.add_foreign_keys() no longer drops ON DELETE/ON UPDATE actions
ForeignKey objects passed to db.add_foreign_keys() were flattened to
plain (table, column, other_table, other_column) tuples before being
handed to transform(), silently discarding their on_delete and
on_update actions. The method now carries ForeignKey objects through
to transform() intact - tuple inputs are converted to ForeignKey
objects up front, which also simplifies the validation loop.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-05 15:42:41 -07:00
Simon Willison
d100264e9c Normalize compound foreign key columns to tuples, promote tuples in docs
ForeignKey.columns and .other_columns are now tuples rather than lists,
both when introspected and when constructed directly (lists are
normalized in __post_init__). Tuples are now the documented form for
specifying compound foreign keys everywhere - in create_table()
foreign_keys=, add_foreign_key() and drop_foreign_keys=:

    foreign_keys=[(("campus_name", "dept_code"), "departments")]

Lists continue to work as input but are no longer documented.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-05 15:10:21 -07:00
Simon Willison
c16edb2dc4 Better type signatures for compound foreign key columns
New ForeignKeyColumns type alias - a column name or a list/tuple of
column names - used by add_foreign_key(), add_foreign_keys() (via the
ForeignKeyTuple alias, replacing its Any slots) and the
ForeignKeyIndicator union, which it also simplifies. Tuples now
type-check anywhere lists are accepted.

ForeignKey.__post_init__ normalizes tuple columns/other_columns to
lists so direct construction with tuples compares equal to
introspected foreign keys.

Refs https://github.com/simonw/sqlite-utils/pull/770/changes#r3525703477

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-05 15:03:43 -07:00
Simon Willison
8443d7f3ba Resolve implicit primary key references in table.foreign_keys
For foreign keys declared as "REFERENCES other_table" with no explicit
columns, PRAGMA foreign_key_list returns None for the referenced
column. The foreign_keys property now resolves these to the other
table's primary key columns, so other_column=None unambiguously
indicates a compound foreign key.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-05 14:42:30 -07:00
Simon Willison
be27a96484 Capture and preserve foreign key ON DELETE/ON UPDATE actions
ForeignKey gains on_delete and on_update fields (default "NO ACTION"),
populated from PRAGMA foreign_key_list. create_table_sql() renders the
corresponding clauses for both inline and compound table-level foreign
keys, which means table.transform() now preserves actions such as
ON DELETE CASCADE - previously they were silently stripped whenever a
table was transformed.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-05 14:40:57 -07:00
Simon Willison
b75edf4b30 add_foreign_key() accepts compound keys, composite FK indexes, refs #594
table.add_foreign_key() and db.add_foreign_keys() now accept lists of
column names to create compound foreign keys:

    table.add_foreign_key(
        ["campus_name", "dept_code"], "departments"
    )

Omitting the other columns uses the compound primary key of the other
table. Duplicate detection compares the full column lists.

db.index_foreign_keys() now creates a single composite index across the
columns of a compound foreign key, rather than an index per column.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-05 14:37:32 -07:00
Simon Willison
7d43fd50e1 transform() now round-trips compound foreign keys, refs #594
Compound foreign keys are passed through table.transform() intact
instead of being degraded to per-column single foreign keys:

- rename= applies to each member column of a compound key
- drop= of any member column drops the whole constraint, matching
  the existing single-column behavior
- drop_foreign_keys= accepts a bare column name (drops any foreign
  key that column participates in) or a tuple of columns (drops the
  compound key with exactly those columns)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-05 14:33:15 -07:00
Simon Willison
577f3011e5 Create tables with compound foreign keys, refs #594
create_table() and friends now accept compound foreign keys, specified
as lists of column names in the existing tuple forms:

    foreign_keys=[
        (["campus_name", "dept_code"], "departments"),
        (["campus_name", "dept_code"], "departments", ["campus_name", "dept_code"]),
    ]

The two-item form guesses the compound primary key of the other table.
Compound keys are rendered as table-level FOREIGN KEY constraints,
while single-column keys keep their inline REFERENCES clauses.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-05 14:30:41 -07:00
Simon Willison
d5bf51df35 Fix TypeError when sorting mixed compound/single foreign keys
sorted() on a foreign_keys list containing both compound (column=None)
and single-column ForeignKeys raised TypeError because dataclass
ordering compared None against str. column/other_column are now
excluded from comparison - ordering and equality use the always
populated columns/other_columns lists instead.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-05 14:26:56 -07:00
Simon Willison
f10459cffb table.foreign_keys now handles compound foreign keys, refs #594
This is a breaking change, since the return type is now a dataclass
and not a namedtuple.
2026-07-05 13:59:25 -07:00