To create another table the basic syntax is 

CREATE TABLE <table_name> (
	<column_name>	<column_type> ) ;

To create a table to hold information about dogs 

   Create table dogs (
	Dog_name		varchar2(20),
	Dog_type		varchar2(20),
	Dog_weight	number ) ;

Table created.


SQL> desc dogs;
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 DOG_NAME                                           VARCHAR2(20)
 DOG_TYPE                                           VARCHAR2(20)
 DOG_WEIGHT                                         NUMBER

This created a table called DOGS with three columns. Two columns hold character data up to 20 characters and the third column holds numeric data.


Delete a table;

DROP TABLE <table_name>;

To delete table dogs
	
     Drop table dogs;

Table dropped.


To insert some data into the dogs table we would use an insert statement like

Insert into dogs  (dog_name, dog_type, dog_weight) values ( 'Homer', 'Golden Retriever', 75 ) ;



This inserts one row into the DB and commits the value;


We can check the content of this table :

SQL> select * from dogs ;


DOG_NAME             DOG_TYPE             DOG_WEIGHT
-------------------- -------------------- ----------
Homer                Golden Retriever             75


Lets say we want to modify the value in this table we can issue an update statement 

UPDATE dogs SET dog_weight = 65 WHERE dog_name = 'Homer' ;


Now reselecting we get 

SQL> select dog_name,dog_weight from dogs ;

DOG_NAME             DOG_WEIGHT
-------------------- ----------
Homer                        65

Lets say we want to add a column called STATUS to the table dogs (An ALTER statement)

SQL> alter table dogs add (status varchar2(10) ) ;

Table altered.

SQL> desc dogs
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 DOG_NAME                                           VARCHAR2(20)
 DOG_TYPE                                           VARCHAR2(20)
 DOG_WEIGHT                                         NUMBER
 STATUS                                             VARCHAR2(10)

There will be no value in that column until we update the table and add a value 
As shown 

SQL> select dog_name,dog_weight,status from dogs ;

DOG_NAME             DOG_WEIGHT STATUS
-------------------- ---------- ----------
Homer                        65



So to add a value to status for the row for Homer we would do an update:

SQL> update dogs set status='Dead' where dog_name='Homer' ;

1 row updated.


Now selecting we get 

SQL> select dog_name,dog_weight,status from dogs ;

DOG_NAME             DOG_WEIGHT STATUS
-------------------- ---------- ----------
Homer                        65 Dead


Let’s add more data  to the same table:


Insert into dogs  (dog_name,dog_type, dog_weight, status) 
values ( 'Sonny','Mutt', 75, 'Dead' ) ;

Insert into dogs  (dog_name,dog_type, dog_weight, status) 
values ( 'Ginger','Golden Retreiver', 45, 'Dead' ) ;



We can select three rows out now:

SQL> select dog_name from dogs;

DOG_NAME
--------------------
Homer
Sonny
Ginger

To delete one of these rows we would type

Delete from dogs where dog_name='Ginger' ;

At the SQL> prompt this would like 

SQL> Delete from dogs where dog_name='Ginger' ;

1 row deleted.



Now reselecting looks like :

SQL> select dog_name from dogs;

DOG_NAME
--------------------
Homer
Sonny



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