This is a SQL command used to display the structure of a
table present in the database.
General Form of DESCRIBE command:
DESCRIBE
tableName
Consider
the below example showing the use of DESCRIBE command to display the structure
of the employees
table present in the database of my Oracle 10g express edition DB
software.
DESCRIBE employees
Output of
above statement:
You can see in above output only the internal
structure of employees table is displayed. It shows different columns
present in tables and the constraints, data-types of column, length of data-types
etc. Here the data present in the table is not displayed but only the internal
structure of the table is displayed.
In some
situation you will not be aware of the internal structure of a table. In such
conditions the DESCRIBE
command will be a great help to you. Consider that I have to display
only a few columns present in the table say employees and its data.
But am not aware how these columns are internally named for employees
table present in a database. In such situation I can make use of DESCRIBE
command.
Below you can
see the use of SELECT statement used to display only two particular
columns of employees table and its data.
select first_name,
salary
from employees
Note: SQL commands
are not case sensitive.
Output of
above statement:
