数据库的三级模式结构由外模式、模式和内模式组成，它适合的数据库类型有Ⅰ．关系型数据库Ⅱ．层次型数据库Ⅲ．网状型数据库

数据库的三级模式结构由外模式、模式和内模式组成，适合数据库类型有______。Ⅰ．关系型数据库Ⅱ．层次型数据库Ⅲ．网状型数据库

数据库的三级模式结构由外模式、模式和内模式组成，它适合( )。Ⅰ．关系型数据库Ⅱ．层次型数据库Ⅲ．网状型数据库

数据库的三级模式结构由外模式、模式和内模式组成，它适合( )。Ⅰ．关系型数据库Ⅱ．层次型数据Ⅲ．网状型数据库

关系数据库数据操作的处理单位是（），层次和网状数据库数据操作的处理单位是记录。

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。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。