ALTER TABLE PurchOutProduct
ADD CONSTRAINT ck_qty_PurchOutProduct CHECK (qty >=0);
GO

ALTER TABLE PurchOutbase
ADD CONSTRAINT ck_qty_PurchOutbase CHECK (qty >=0);
GO

------解决方案--------------------
SQL code
用检查就行了

Create table PurchOutProduct(
Qty int check (Qty>0)
)

------解决方案--------------------
触发器这样实现



SQL code
Create table PurchOutProduct(
Qty int
)
go
Create trigger tr_PurchOutProduct on PurchOutProduct
for insert
as
if exists(select 1 from inserted  where Qty<=0)
    rollback tran

------解决方案--------------------
SQL code
Create trigger tr_PurchOutProduct on PurchOutProduct
for insert
as
insert into PurchOutProduct 
select * from  inserted where not exists (select 1 from inserted where qty<0)