A constraint in a table is defined with the INITIALLY IMMEDIATE clause. You executed the ALTER TABLEcommand with the ENABLE VALIDATE option to enable the constraint that was disabled. What are the twoeffects of this command()
A. It fails if any existing row violates the constraint.
B. It does not validate the existing data in the table.
C. It enables the constraint to be enforced at the end of each transaction.
D. It prevents insert, update, and delete operations on the table while the constraint is in the process of beingenabled
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男性,28岁,自幼反复出现咳嗽、咯黄痰,偶有痰中带血,曾有两次咯血量在100ml以上,胸片见双下肺纹理粗乱。应考虑()女性,25岁,近1年反复出现咳嗽、低热,偶有痰中带血,胸片双下肺斑片影,沿支气管走行播散。应考虑()男性,65岁,1年内出现右下肺炎2次,咳嗽、痰中带血,胸片见右下肺不张。应考虑()
A. 继发性肺结核
B. 肺炎球菌性肺炎
C. 支气管扩张
D. 支气管内膜结核
E. 肺癌
关于急性毒性试验中动物选择的原则说法错误的是()
A. 一般要求选择两个不同种属
B. 通常选择刚断乳动物
C. 雌雄各半
D. 常用哺乳类动物
E. 每组实验动物的数量因求LD50方法不同而不同