[
  {
    "type": "alter_table",
    "description": "Modify scheduleShifts table - nullable employeeId for open shifts, add publishing columns",
    "database": "{{store}}",
    "check_query": "SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = 'scheduleShifts' AND COLUMN_NAME = 'publishedAt'",
    "sql": "ALTER TABLE `scheduleShifts`\n  MODIFY COLUMN `employeeId` int(10) unsigned NULL COMMENT 'FK to employee - NULL for open shifts',\n  ADD COLUMN `publishedAt` datetime NULL COMMENT 'When this shift was published to employees',\n  ADD COLUMN `publishedByUserId` int(10) unsigned NULL COMMENT 'Manager who published the shift',\n  ADD KEY `idx_published` (`publishedAt`),\n  ADD KEY `idx_open_shifts` (`employeeId`, `shiftStart`)"
  }
]