优化考勤记录

sql/init.sql

@@ -267,6 +267,36 @@ PREPARE stmt FROM @sql;
 EXECUTE stmt;
 DEALLOCATE PREPARE stmt;
 
+-- attendance_records 表：添加 slot 字段（如不存在）
+SET @column_exists = (
+    SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS
+    WHERE TABLE_SCHEMA = 'classmanagerdb'
+    AND TABLE_NAME = 'attendance_records'
+    AND COLUMN_NAME = 'slot'
+);
+SET @sql = IF(@column_exists = 0,
+    'ALTER TABLE `attendance_records` ADD COLUMN `slot` VARCHAR(20) DEFAULT ''morning'' COMMENT ''时段: morning/afternoon/evening'' AFTER `date`',
+    'SELECT ''attendance_records.slot already exists'' AS message'
+);
+PREPARE stmt FROM @sql;
+EXECUTE stmt;
+DEALLOCATE PREPARE stmt;
+
+-- 删除旧唯一键并添加新唯一键（含slot）
+SET @uk_exists = (
+    SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
+    WHERE TABLE_SCHEMA = 'classmanagerdb'
+    AND TABLE_NAME = 'attendance_records'
+    AND CONSTRAINT_NAME = 'uk_student_date'
+);
+SET @sql = IF(@uk_exists > 0,
+    'ALTER TABLE `attendance_records` DROP INDEX `uk_student_date`, ADD UNIQUE KEY `uk_student_date_slot` (`student_id`, `date`, `slot`)',
+    'SELECT ''uk_student_date does not exist, skipping'' AS message'
+);
+PREPARE stmt FROM @sql;
+EXECUTE stmt;
+DEALLOCATE PREPARE stmt;
+
 -- 迁移：semester_archives 表新增 attendance_present 字段
 SET @column_exists = (
     SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS