Oracle:Initial Queries

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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 1.1

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.

Next Step

This concludes setting up the Oracle database. Return now to the Workbook for the next section.