数据库应用程序与数据的逻辑组织和数据的物理存储方式无关，表明了数据库的数据具有 ( )。

一个数据表中只能有一个主键约束，但可以有多个UNIQUE约束。

主键约束用来强制数据的（）完整性。

口服补液及时纠正脱水，应用ORS，说法正确的是（）

Every deliberate act of wrongdoing by the master or any of the crew against the ship or cargo，without the authorization or privity of the Shipowner or his agent，is（）.

（）, or drum is used for hauling in or letting out the wires or ropes which will fasten the ship to the shore.

A salvor may be（）the whole or part of the payment due under Salvage Convention to the extent that the salvage operations have become necessary or more difficult because of fault or neglect on his part or if the salvor has been guilty of fraud or other dishonest conduct.

The （） is used for hauling in or letting out the wires or ropes.

Vessels must be（）valid certificate of nationality or certificated of registry or license.

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

一个数据表中只能有一个主键约束，但可以有多个UNIQUE约束。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。