-- ================================================================
-- 贫困生认定申请表 teacher_name 字段修复脚本
-- 文件: database_fix_teacher_name.sql
-- 功能: 添加缺失的 teacher_name 字段，并确保允许NULL
-- ================================================================

USE hzdyjs_xg;

-- 1. 检查 teacher_name 字段是否存在
SELECT '开始检查 teacher_name 字段...' AS message;

SELECT
    COLUMN_NAME,
    IS_NULLABLE,
    COLUMN_DEFAULT,
    DATA_TYPE
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = 'hzdyjs_xg'
  AND TABLE_NAME = 'jcbt_poverty_application'
  AND COLUMN_NAME = 'teacher_name';

-- 2. 添加 teacher_name 字段（如果不存在）
SET @sql = '';
SELECT COUNT(*) INTO @count
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = 'hzdyjs_xg'
  AND TABLE_NAME = 'jcbt_poverty_application'
  AND COLUMN_NAME = 'teacher_name';

SELECT IF(@count = 0,
    'ALTER TABLE jcbt_poverty_application ADD COLUMN teacher_name varchar(100) DEFAULT NULL COMMENT ''班主任教师姓名'' AFTER teacher_id;',
    'SELECT ''teacher_name 字段已存在，检查是否需要修改属性'' AS result;'
) INTO @sql;

PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

-- 3. 修改 teacher_name 字段为允许 NULL（如果字段存在且不允许NULL）
SET @sql = '';
SELECT COUNT(*) INTO @count
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = 'hzdyjs_xg'
  AND TABLE_NAME = 'jcbt_poverty_application'
  AND COLUMN_NAME = 'teacher_name'
  AND IS_NULLABLE = 'NO';

SELECT IF(@count > 0,
    'ALTER TABLE jcbt_poverty_application MODIFY COLUMN teacher_name varchar(100) DEFAULT NULL COMMENT ''班主任教师姓名'';',
    'SELECT ''teacher_name 字段已允许NULL'' AS result;'
) INTO @sql;

PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

SELECT '✅ teacher_name 字段修复完成' AS message;

-- 4. 添加 teacher_id 字段（如果不存在）
SET @sql = '';
SELECT COUNT(*) INTO @count
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = 'hzdyjs_xg'
  AND TABLE_NAME = 'jcbt_poverty_application'
  AND COLUMN_NAME = 'teacher_id';

SELECT IF(@count = 0,
    'ALTER TABLE jcbt_poverty_application ADD COLUMN teacher_id bigint(20) DEFAULT NULL COMMENT ''班主任教师ID'' AFTER class_name;',
    'SELECT ''teacher_id 字段已存在'' AS result;'
) INTO @sql;

PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

-- 5. 确保 teacher_id 字段允许 NULL
SELECT '检查 teacher_id 字段...' AS message;

SET @sql = '';
SELECT COUNT(*) INTO @count
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = 'hzdyjs_xg'
  AND TABLE_NAME = 'jcbt_poverty_application'
  AND COLUMN_NAME = 'teacher_id'
  AND IS_NULLABLE = 'NO';

SELECT IF(@count > 0,
    'ALTER TABLE jcbt_poverty_application MODIFY COLUMN teacher_id bigint(20) DEFAULT NULL COMMENT ''班主任教师ID'';',
    'SELECT ''teacher_id 字段已允许NULL或不存在'' AS result;'
) INTO @sql;

PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

SELECT '✅ teacher_id 字段修复完成' AS message;

-- 6. 验证修复结果
SELECT '=== 修复结果验证 ===' AS message;

SELECT
    COLUMN_NAME AS '字段名',
    DATA_TYPE AS '数据类型',
    IS_NULLABLE AS '允许NULL',
    COLUMN_DEFAULT AS '默认值',
    COLUMN_COMMENT AS '注释'
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = 'hzdyjs_xg'
  AND TABLE_NAME = 'jcbt_poverty_application'
  AND COLUMN_NAME IN ('teacher_id', 'teacher_name')
ORDER BY ORDINAL_POSITION;

-- 7. 显示完整的字段结构确认
SELECT '=== 相关字段结构确认 ===' AS message;

SELECT
    COLUMN_NAME AS '字段名',
    DATA_TYPE AS '数据类型',
    IS_NULLABLE AS '允许NULL',
    COLUMN_DEFAULT AS '默认值',
    COLUMN_COMMENT AS '注释'
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = 'hzdyjs_xg'
  AND TABLE_NAME = 'jcbt_poverty_application'
  AND COLUMN_NAME IN (
    'class_id', 'class_name', 'teacher_id', 'teacher_name', 'recognition_group'
  )
ORDER BY ORDINAL_POSITION;

SELECT '🎉 teacher_name 和 teacher_id 字段修复完成！' AS message;
SELECT '📝 请重启后端服务以生效！' AS note;