Exam 3: The Relational Data Model

When more than one column in a table is needed to uniquely identify a row,this type of primary key is called a(n)________________ .

In the set-oriented database terminology,a(n)____________ is synonymous with a row.

The _______________ clause of the CREATE TABLE statement is used to define primary and foreign keys.

In the record-oriented database terminology,a(n)_____________ is synonymous with a column.

In the alternative terminology for relational databases,the ______________ -oriented terminology uses the terms file,record and field,and appeals to information systems professionals.

The relational algebra operator that produces a subset of the columns of the input table is the _________________ operator.

When the join condition specifies that rows from two or more tables have an identical value in one or more columns,this join is called a(n)_________________ .

To be union compatible,each table must have the same number of columns,and there must be positional correspondence between the columns with regards to the data types.

The following data are in the tables Employee (primary key: Empno) and Department (primary key: Deptno). The questions refer to row numbers of this table. The first row of each table is row #1. Empdeptno in table Employee is a foreign key that refers to Deptno in the table Department. Deptmgr in the table Department is a foreign key that refers to Empno in the table Employee. Table~Employee\\ \begin{array}{|l|l|l|l|l|} \hline \text { Empno } & \text { Empname } & \text { Empdeptro } & \text { Empsalary } & \text { Emptitle } \\ \hline 555 & \text { Keamy } & 200 & 7000 & \text { manager } \\ \hline 666 & \text { Williams } & 100 & 8000 & \text { manager } \\ \hline 777 & \text { Haberle } & 200 & 5000 & \text { clerk } \\ \hline 888 & \text { Haberle } & 200 & 5000 & \text { clerk } \\ \hline & \text { Johnson } & 300 & 4000 & \text { analyst } \\ \hline 889 & \text { Dupont } & 400 & & \\ \hline & \text { McCabe } & 400 & 6000 & \text { programmer } \\ \hline 999 & \text { Lopez } & & 9000 & \text { manager } \\ \hline \end{array} Table~Department\\ \begin{array}{|l|l|l|l|} \hline \text { Deptno } & \text { Deptname } & \text { Deptcity } & \text { Deptmgr } \\ \hline 100 & \text { Logistics } & \text { Wichita } & 666 \\ \hline 200 & \text { Finance } & \text { Boise } & 555 \\ \hline 300 & \text { Marketing } & \text { Pierre } & 666 \\ \hline \end{array} -The values shown in the table Department:

Table~Employee\\ \begin{array}{|l|l|l|l|l|} \hline \text { Empno } & \text { Empname } & \text { Empdeptno } & \text { Empsalary } & \text { Emptitle } \\ \hline \end{array} Each row of the table Department describes a department. Deptno is the primary key. Deptmgr (Department manager) refers to Empno in table Employee. Table~Department\\ \begin{array}{|l|l|l|l|} \hline \text { Deptno } & \text { Deptname } & \text { Deptcity } & \text { Deptmgr } \\ \hline \end{array} Each row of the table Project describes a project. The primary key is Projno. Projmgr (project manager. refers to Empno in the table Employee. Table~Project\\ \begin{array}{|l|l|l|} \hline \text { Projno } & \text { Projname } & \text { Projmgr } \\ \hline \end{array} The table Projstaff indicates the staff assigned to various Projects. Table~Project\\ \begin{array}{|l|l|l|l|l|} \hline \text { Prstno } & \text { Prstempno } & \text { Prsthours } & \text { Prstdate } & \text { Prstasgtno } \\ \hline \end{array} The combination of columns Prstno, Prstempno is a candidate key. There could be other candidate keys. Prstempno is the Empno in table Employee of the employee working on project number Prstno, which refers to Projno in the table Project. The meaning of Prstasgtno is left undefined. -Which of the following columns is not a foreign key?

The relational algebra operator restrict produces a subset of columns of the input table,while the operator project produces a subset of rows.

To prohibit actions on referenced rows to occur when a record is deleted,you would specify the clause __________________________ in the CREATE TABLE statement.

In an outer join operation,the join condition is equality,one of the join columns is discarded in the result table,and the join columns have the same unqualified name.

To cause the same action to be performed on referenced rows when a record is updated,you would specify the clause _________________________ in the CREATE TABLE statement.

The tables Dept1 and Dept2 are as follows Table~Dept1\\ \begin{array}{|l|l|l|l|} \hline \text { Deptno } & \text { Deptname } & \text { Deptcity } & \text { Deptmgr } \\ \hline 100 & \text { Logistics } & \text { Wichita } & 666 \\ \hline 200 & \text { Finance } & \text { Boise } & 555 \\ \hline 300 & \text { Marketing } & \text { Pierre } & 666 \\ \hline \end{array} Table~Dept2\\ \begin{array}{|l|l|l|l|} \hline \text { Deptno } & \text { Deptname } & \text { Deptcity } & \text { Deptmgr } \\ \hline 200 & \text { Finance } & \text { Boise } & 555 \\ \hline 300 & \text { Marketing } & \text { Pierre } & 666 \\ \hline 400 & \text { Sales } & \text { Reno } & 666 \\ \hline \end{array} -A relational algebra operator applied to tables Dept1 and Dept2 produces the following result: Deptno Deptname Deptcity Deptmgr 100 Logistics Wichita 666 The operation is: