In
`@src/Appwrite/Platform/Modules/Databases/Http/Databases/Collections/Documents/Action.php`:
- Around line 254-281: The validateRelationship method currently overwrites any
client-provided associative-array relation $id by always assigning ID::unique();
change this so that when $relation is an associative array you only assign
ID::unique() if $relation['$id'] is not set or empty, and if a $id is provided
validate it with CustomId() exactly like the string/Document path; ensure the
validation and potential Exception::GENERAL_BAD_REQUEST uses the
validator->getDescription(), and return the normalized Document (wrapping the
array in new Document($relation)) only after validation so custom IDs are not
silently replaced (references: validateRelationship, Document, CustomId,
Exception::GENERAL_BAD_REQUEST).

In `@tests/e2e/Services/Databases/TablesDB/DatabasesBase.php`:
- Around line 7682-7695: The test currently posts a relationship via
$this->client->call to '/tablesdb/.../columns/relationship' using
Database::RELATION_ONE_TO_MANY and then just sleep(1), which can cause false
negatives if the column/relationship isn't ready; modify the test to assert the
relationship creation response (e.g., check response code and returned
column/relationship id) immediately after the call and replace the blind sleep
with a short poll that calls the column list/get endpoint until the new column
id appears or a timeout elapses before proceeding to negative ID-validation
cases.

In
`@src/Appwrite/Platform/Modules/Databases/Http/Databases/Collections/Documents/Create.php`:
- Around line 311-319: The loop currently calls validateRelationship($relation)
before converting placeholder IDs, causing CustomId validation to reject
ID::unique() placeholders; move normalization so that you assign missing
$relation['$id'] = ID::unique() (and convert string "unique()" if your code uses
that placeholder) and wrap $relation into new Document($relation) prior to
calling validateRelationship, or alternatively update validateRelationship to
accept the placeholder (e.g., treat ID::unique() / "unique()" as valid) — adjust
the foreach around $relations, the validateRelationship method, and the Document
creation logic accordingly.

In
`@src/Appwrite/Platform/Modules/Databases/Http/Databases/Collections/Documents/Update.php`:
- Around line 203-211: The loop over $relations validates each relation before
normalizing the ID placeholder, causing inline relationship updates using
ID::unique() to fail; move the normalization step that replaces $relation['$id']
= ID::unique() (or otherwise resolves the "unique()" placeholder) to occur
before calling validateRelationship($relation), or update validateRelationship
to accept the placeholder; specifically adjust the foreach that currently calls
$this->validateRelationship($relation) prior to converting array relations into
Document instances so that normalization of '$id' (and conversion to Document)
happens first, then call validateRelationship on the normalized Document/array.

In `@tests/e2e/Services/Databases/TablesDB/DatabasesBase.php`:
- Around line 7695-7709: The loop that polls for the relationship column using
$maxAttempts and the for ($i = 0; $i < $maxAttempts; $i++) construct can
silently continue if the 'children' column never appears; add a boolean flag
(e.g., $found = false) before the loop, set $found = true and break when
in_array('children', $columnKeys) is true, and after the loop assert that $found
is true (or fail the test with a clear message including $databaseId and
$parentTableId); optionally include the last $columns response/status in the
failure message for debugging.

In
`@src/Appwrite/Platform/Modules/Databases/Http/Databases/Collections/Documents/Action.php`:
- Around line 253-275: The validateRelationship method currently ignores values
that are not Document, string, or associative array; update validateRelationship
to reject unsupported types by adding an else branch that throws an Exception
(use Exception::GENERAL_BAD_REQUEST) with a clear message (e.g. "Unsupported
relationship value type") so callers get a validation error for inputs like
integers/booleans; keep existing behavior for Document, string, and associative
array branches and reuse the same Exception class as used for CustomId
validation.

In
`@src/Appwrite/Platform/Modules/Databases/Http/Databases/Collections/Documents/Action.php`:
- Around line 261-275: After extracting $relationId (from Document, string, or
associative array) add a strict type guard so non-string values never reach
CustomId::isValid(): before creating the CustomId validator in Action.php, check
is_string($relationId) and if not throw Exception::GENERAL_BAD_REQUEST with an
appropriate message; then call (new CustomId())->isValid($relationId) and use
getDescription() as before. This ensures relationId, CustomId::isValid, and the
Exception path are only executed for string IDs and prevents TypeError 500s.