Oracle:Initial Queries

Initial Queries

Try the following commands and exercises:

Getting Information about the Attributes of a Table

To get a description of a particular table use the DESCRIBE command.

To describe the table EMP:

 describe emp 

Note, describe is a command proprietary to Oracle and is not part of the SQL standard. These commands are part of the Plus commands Oracle provides and do not need a semi-colon after them.

Exercise 1

Type in the SQL code to display the structure of the CUSTOMER table.

The result should be similar to the following:

Name                                      Null?    Type
----------------------------------------- -------- ----------------------------
CNO                                                NUMBER(4)
ORDERDATE                                          DATE
NAME                                               VARCHAR2(15)
CITY                                               VARCHAR2(15)
COUNTRY                                            VARCHAR2(15)
PNO                                                NUMBER(4)
DESCRIPTION                                        VARCHAR2(20)
QTY                                                NUMBER(4)

Type in the following commands separately:

 describe dept

 select * from dept;

 select * from emp;

 describe salgrade

 select * from salgrade;

Make notes on how the results differ.