现在有个表,要求某个字段在表中唯一,为了前台系统提示的友好性,选择用触发器而不用唯一索引,我的触发器是这样写的:
- SQL code
create trigger [dbo].[tr_m_b_material_standard_relations_i] on [dbo].[t_m_b_material_standard_relations]for insertasbeginif exists(select 1 from INSERTED _a WHERE material_id IN (SELECT material_id FROM dbo.t_m_b_material_standard_relations)) begin select @msg='物料不允许重复!' raiserror(@msg,16,1) rollback tran return endend
现在的问题是,我在表中插入的数据, material_id 字段不重复,触发器也会弹出“物料不允许重复”,这是为什么呢?
有没有办法查看一下inserted表里的数据呢?
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- SQL code
--for insert,此时insert的记录在表中是已经可以选出来的了create trigger [dbo].[tr_m_b_material_standard_relations_i] on [dbo].[t_m_b_material_standard_relations]for insertasdeclare @msg varchar(100);if (select count(1) from inserted i,t_m_b_material_standard_relations t where i.material_id=t.material_id)>1 begin select @msg='物料不允许重复!' raiserror(@msg,16,1) rollback tran returnendgo
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- SQL code
--刚才那种写法多条一起插入时有问题,这样写吧create trigger [dbo].[tr_m_b_material_standard_relations_i] on [dbo].[t_m_b_material_standard_relations]for insertasdeclare @msg varchar(100);if exists (select 1 from inserted i,t_m_b_material_standard_relations t where i.material_id=t.material_id group by i.material_id having count(1)>1) begin select @msg='物料不允许重复!' raiserror(@msg,16,1) rollback tran returnendgo
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inserted/deleted两个表存在于触发器内。所以你查不了。你可以在触发器里面select出来或者保存到一个实体表中再检查。
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