Getting Help

While you use SQL*Plus, you may find that you need to list column definitions for a table, or start and stop the display that scrolls by. You may also need to interpret error messages you receive when you enter a command incorrectly or when there is a problem with Oracle or SQL*Plus. The following sections describe how to get help for those situations.

Listing a Table Definition

To see the definitions of each column in a given table or view, use the SQL*Plus DESCRIBE command.

Example 2-6 Using the DESCRIBE Command

To list the column definitions of the columns in the sample view EMP_DETAILS_VIEW, enter

DESCRIBE EMP_DETAILS_VIEW;


 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 EMPLOYEE_ID                               NOT NULL NUMBER(6)
 JOB_ID                                    NOT NULL VARCHAR2(10)
 MANAGER_ID                                         NUMBER(6)
 DEPARTMENT_ID                                      NUMBER(4)
 LOCATION_ID                                        NUMBER(4)
 COUNTRY_ID                                         CHAR(2)
 FIRST_NAME                                         VARCHAR2(20)
 LAST_NAME                                 NOT NULL VARCHAR2(25)
 SALARY                                             NUMBER(8,2)
 COMMISSION_PCT                                     NUMBER(2,2)
 DEPARTMENT_NAME                           NOT NULL VARCHAR2(30)
 JOB_TITLE                                 NOT NULL VARCHAR2(35)
 CITY                                      NOT NULL VARCHAR2(30)
 STATE_PROVINCE                                     VARCHAR2(25)
 COUNTRY_NAME                                       VARCHAR2(40)
 REGION_NAME                                        VARCHAR2(25)

Note: DESCRIBE accesses information in the Oracle data dictionary. You can also use SQL SELECT commands to access this and other information in the database. See your Oracle9i SQL Reference for details.

Listing PL/SQL Definitions

To see the definition of a function or procedure, use the SQL*Plus DESCRIBE command.

Example 2-7 Using the DESCRIBE Command

To list the definition of a function called AFUNC, enter

DESCRIBE afunc


FUNCTION afunc RETURNS NUMBER
Argument Name   Type     In/Out   Default?
--------------- -------- -------- ---------
F1              CHAR     IN
F2              NUMBER   IN

Controlling the Display

Suppose that you wish to stop and examine the contents of the screen while displaying a long report or the definition of a table with many columns. The display will pause while you examine it. To continue, press Resume.

If you wish, you can use the PAUSE variable of the SQL*Plus SET command to have SQL*Plus pause after displaying each screen of a query or report. For more information, refer to the SET command in Chapter 8.

Interpreting Error Messages

If SQL*Plus detects an error in a command, it displays an error message. See Appendix A, "SQL*Plus Error Messages" for a list of SQL*Plus error messages.

Example 2-8 Interpreting an Error Message

If you attempt to execute a file that does not exist or is unavailable by entering:

START EMPLYYES.SQL

An error message indicates that the table does not exist:

SP2-0310: unable to open file "emplyyes.sql"

You will often be able to figure out how to correct the problem from the message alone. If you need further explanation, take one of the following steps to determine the cause of the problem and how to correct it:

• If the error is a numbered error beginning with the letters "SP2", look up the SQL*Plus message in Appendix A, "SQL*Plus Error Messages" of this guide.

• If the error is a numbered error beginning with the letters "CPY" look up the SQL*Plus COPY command message in Appendix A, "SQL*Plus Error Messages" of this guide.

• If the error is a numbered error beginning with the letters "ORA", look up the Oracle message in the Oracle9i Error Messages guide or in the Oracle installation and user's guides provided for your operating system.

If the error is unnumbered, look up correct syntax for the command that generated the error in Chapter 8, "Command Reference" of this guide for a SQL*Plus command, in the Oracle9i SQL Reference for a SQL command, or in the PL/SQL User's Guide and Reference for a PL/SQL block. Otherwise, contact your DBA.