Allow empty insert for tables with all defaults (#1280)

[dimitri-yatsenko]

Summary

• When all attributes have defaults (autoincrement, nullable, or explicit default), allow inserting empty dicts via table.insert1({})
• Generates SQL: INSERT INTO table () VALUES ()
• For tables with required fields, raise a clear error listing which attributes need values

Changes

src/datajoint/table.py:

• In __make_row_to_insert(): Check if empty insert is allowed based on attribute defaults
• In _insert_rows(): Handle empty field_list case for SQL generation

tests/integration/test_insert.py:

• Added TestEmptyInsert test class with:
  • test_empty_insert_all_defaults: Verify empty insert works for all-defaults table
  • test_empty_insert_multiple: Verify multiple empty inserts work
  • test_empty_insert_required_fields_error: Verify clear error for tables with required fields

Example

@schema
class EventLog(dj.Manual):
    definition = """
    id : int auto_increment
    ---
    timestamp=CURRENT_TIMESTAMP : datetime
    notes=null : varchar(200)
    """

# Now works - uses all defaults
EventLog().insert1({})

# Error if required fields exist
class RequiredFields(dj.Manual):
    definition = """
    id : int
    ---
    value : varchar(100)
    """

RequiredFields().insert1({})
# Raises: DataJointError: Cannot insert empty row. The following attributes require values: ['id', 'value']

Test Plan

• Empty insert succeeds for tables with all defaults (autoincrement + nullable + explicit defaults)
• Multiple empty inserts generate unique autoincrement values
• Empty insert on tables with required fields raises clear error listing missing attributes
• All existing insert tests pass

Closes #1280

🤖 Generated with Claude Code