The relational database model requires the data be(71)through programs that don't rely on the position of the data in the database. This is in direct(72)to the other database mode, where the program has to follow a series of pointers to the data it seeks. A program(73)a relational database simply asks for the data it seeks; the DBMS performs the necessary searches and(74)the information. The(75)on how the search is done are specific to the DBMS and vary from product to product.

A．accessed

B．moved

C．read

D．wrote

[单选题]Relational Model表示（）。A . 关系模型B . 数据结构C . 网络D . 实体

[单选题]Arelation(from the relational database model)consistsof(由⋯⋯组成)a set of tuples(元组),whichimplies(意味着)that().A．all tuples in a relation must be distinct(独一无二的)B．every relation has a key(键)C．all of the aboveD．for any two tuples,the values associated with

[单选题]( ) is a query language for manipulating data in a relational database.A.As

[单选题]The constant growth model requires which of the following?A.gk.C.gD.

[单选题]When a regulatory agency requires a monopolist to use average cost pricing,

[单选题]SQL Server is a RDBMS(Relational Database Management System)made by Microsoft.This means that the data is stored in two dimensional (74) .(74) A．documentsB．databasesC．filesD．tables

[单选题]SQL Server is a RDBMS(Relational Database Management System)made by Microsoft. This means that the data is stored in two dimensional(70)。A．documentsB．databasesC．filesD．tables

[单选题]Cross scavenging requires the fitting of （） to prevent air or exhaust gas escape when the piston is at the top of the stroke.A . a exhaust valveB . a piston skirtC . a piston crownD . an air suction valve

[单选题]An analyst does research about ratio impact according to the dividend disco

[单选题]In developing a hospital database, it is determined that on the average, each patient will have 6 treatments during a hospital stay.The average length of a stay is three days.The hospital has 1000 beds.There are on the average 800 patients occupying