用酵母菌使葡萄汁发酵生产葡萄酒,酒精含量不超过12%-16%。()
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本质安全电路是指在规定的试验条件下,___________或______________状态下产生的电火花和热效应,均不能点燃规定的爆炸性混合物的电路.
You are planning to import customer data from the Customer table and the Country table in your SQL Server 2000 database into a SQL Server 2005 database. You want to ensure that during the import process,each value in the CountryCode column of the Customer table has a corresponding record in the CountryCode column in the Country table of the SQL Server 2005 database. You define a foreign key between these two tables. Thus,referential integrity will guarantee that the import routine fails if there are any records where a CountryCode value does not exist in the Country table but does exist in the Customer table. You need to ensure that the import process does not fail if records are encountered that do not exist in the Country table. What should you do?()
A. Drop the foreign key. Import the data by using the script. Re-create the foreign key.
B. Create a CHECK constraint.
Create a DML INSTEAD OF trigger that writes the failed records to a file or table.
D. Create a DML AFTER trigger that writes the failed records to a file or table.
脑震荡患者会出现“逆行性遗忘”现象。
A. 正确
B. 错误