512.Which two statements correctly describe the relationship among the Scheduler components: job,
program, and schedule? (Choose two)
A. A job is specified as part of a program definition
B. A program can be used in the definition of multiple jobs
C. A program and job can be specified as part of a schedule definition
D. A program and schedule can be specified as part of a job definition
Answer: A
答案解析:
参考:http://docs.oracle.com/cd/E11882_01/server.112/e25494/schedover.htm#ADMIN12374
http://docs.oracle.com/cd/E11882_01/server.112/e25494/schedover.htm#ADMIN12357
正确答案BD
Programs
A program object (program) describes what is to be run by the Scheduler. A program includes:
-
An action: For example, the name of a stored procedure, the name of an executable found in the operating system file system (an "external executable"), or the text of a PL/SQL anonymous block.
-
A type:
STORED_PROCEDURE
,PLSQL_BLOCK
, orEXTERNAL
, whereEXTERNAL
indicates an external executable. -
Number of arguments: The number of arguments that the stored procedure or external executable accepts.
A program is a separate entity from a job. A job runs at a certain time or because a certain event occurred, and invokes a certain program. You can create jobs that point to existing program objects, which means that different jobs can use the same program and run the program at different times and with different settings. With the right privileges, different users can use the same program without having to redefine it. Therefore, you can create program libraries, where users can select from a list of existing programs.
If a stored procedure or external executable referenced by the program accepts arguments, you define these arguments in a separate step after creating the program. You can optionally define a default value for each argument.
How Programs, Jobs, and Schedules are Related
To define what is executed and when, you assign relationships among programs, jobs, and schedules. Figure 28-5 illustrates examples of such relationships.
Figure 28-5 Relationships Among Programs, Jobs, and Schedules

Description of "Figure 28-5 Relationships Among Programs, Jobs, and Schedules"
To understand Figure 28-5, consider a situation where tables are being analyzed.
In this example, program P1
analyzes a table using the DBMS_STATS
package. The program has an input parameter for the table name. Two jobs, J1
and J2
, both point to the same program, but each supplies a different
table name. Additionally, schedule S1
specifies a run time of 2:00 a.m. every day. The end result is that the two tables named in J1
and J2
are analyzed daily at 2:00 a.m.
Note that J4
points to no other entity, so it is self-contained with all relevant information defined in the job itself. P2
, P9
and S2
illustrate that you can leave a program
or schedule unassigned if you want. You can, for example, create a program that calculates a year-end inventory and temporarily leave it unassigned to any job.