140 lines
5.1 KiB
PL/PgSQL
140 lines
5.1 KiB
PL/PgSQL
-- =====================================================================================
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-- 4. 创建聊天会话表 (ml_chat_rooms)
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-- 用于优化聊天列表查询性能，维护用户与商家的会话状态
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-- 依赖表: public.ak_users, public.ml_chat_messages
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-- =====================================================================================
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-- 1. 创建表结构
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CREATE TABLE IF NOT EXISTS public.ml_chat_rooms (
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id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
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user_id UUID NOT NULL REFERENCES public.ak_users(id) ON DELETE CASCADE, -- 消费者ID
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merchant_id UUID NOT NULL, -- 商家ID/店铺ID
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shop_name VARCHAR(100), -- 缓存店铺名称
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shop_logo TEXT, -- 缓存店铺Logo
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last_message TEXT, -- 最后一条消息内容预览
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last_message_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(), -- 最后一条消息时间
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unread_count INTEGER DEFAULT 0, -- 未读消息数
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is_top BOOLEAN DEFAULT FALSE, -- 是否置顶
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created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
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updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
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-- 确保同一个用户和同一个商家只有一个会话
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UNIQUE(user_id, merchant_id)
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);
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COMMENT ON TABLE public.ml_chat_rooms IS '聊天会话列表表';
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-- 2. 开启 RLS
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ALTER TABLE public.ml_chat_rooms ENABLE ROW LEVEL SECURITY;
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-- 3. RLS 策略
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-- 策略：用户只能查自己的会话
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CREATE POLICY ml_chat_rooms_select_policy ON public.ml_chat_rooms
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FOR SELECT USING (
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auth.uid() = (SELECT auth_id FROM public.ak_users WHERE id = user_id)
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);
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-- 策略：允许插入（通常由触发器或后端逻辑维护）
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CREATE POLICY ml_chat_rooms_insert_policy ON public.ml_chat_rooms
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FOR INSERT WITH CHECK (
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auth.uid() = (SELECT auth_id FROM public.ak_users WHERE id = user_id)
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);
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-- 策略：允许更新（如清除未读数）
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CREATE POLICY ml_chat_rooms_update_policy ON public.ml_chat_rooms
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FOR UPDATE USING (
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auth.uid() = (SELECT auth_id FROM public.ak_users WHERE id = user_id)
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);
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-- =====================================================================================
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-- 4. 触发器函数：自动维护会话列表
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-- =====================================================================================
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CREATE OR REPLACE FUNCTION public.handle_new_chat_message()
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RETURNS TRIGGER AS $$
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DECLARE
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v_user_id UUID;
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v_merchant_id UUID;
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v_shop_name TEXT;
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v_shop_logo TEXT;
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v_is_from_user BOOLEAN;
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v_count_inc INTEGER;
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BEGIN
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-- 确定谁是用户，谁是商家
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-- 假设 is_from_user 为 true 时，sender_id 是用户，receiver_id 是商家
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-- 假设 is_from_user 为 false 时，sender_id 是商家，receiver_id 是用户
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v_is_from_user := NEW.is_from_user;
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IF v_is_from_user THEN
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v_user_id := NEW.sender_id;
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v_merchant_id := NEW.receiver_id;
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v_count_inc := 0; -- 用户自己发的，未读数不变
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ELSE
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v_user_id := NEW.receiver_id;
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v_merchant_id := NEW.sender_id;
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v_count_inc := 1; -- 商家发的，用户未读数 +1
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END IF;
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-- 尝试更新用户的会话
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UPDATE public.ml_chat_rooms
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SET
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last_message = NEW.content,
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last_message_at = NEW.created_at,
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updated_at = NOW(),
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unread_count = unread_count + v_count_inc
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WHERE user_id = v_user_id AND merchant_id = v_merchant_id;
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-- 如果没有更新到任何行（说明会话不存在），则插入新会话
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IF NOT FOUND THEN
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-- 尝试从 ml_shops 表获取店铺信息（如果有的话）
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BEGIN
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SELECT shop_name, shop_logo INTO v_shop_name, v_shop_logo
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FROM public.ml_shops
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WHERE merchant_id = v_merchant_id
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LIMIT 1;
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EXCEPTION WHEN OTHERS THEN
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-- 忽略错误，使用默认值
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v_shop_name := '未知店铺';
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v_shop_logo := '';
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END;
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-- 如果没查到，给个默认名
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IF v_shop_name IS NULL THEN
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v_shop_name := '店铺 ' || substr(v_merchant_id::text, 1, 8);
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END IF;
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INSERT INTO public.ml_chat_rooms (
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user_id,
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merchant_id,
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last_message,
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last_message_at,
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unread_count,
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shop_name,
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shop_logo
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)
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VALUES (
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v_user_id,
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v_merchant_id,
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NEW.content,
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NEW.created_at,
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v_count_inc,
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v_shop_name,
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v_shop_logo
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);
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END IF;
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RETURN NEW;
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END;
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$$ LANGUAGE plpgsql SECURITY DEFINER;
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-- 5. 创建触发器
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DROP TRIGGER IF EXISTS on_chat_message_inserted ON public.ml_chat_messages;
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CREATE TRIGGER on_chat_message_inserted
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AFTER INSERT ON public.ml_chat_messages
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FOR EACH ROW
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EXECUTE FUNCTION public.handle_new_chat_message();
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