Wednesday, May 20, 2015

Computers-How to write SQL in Oracle (practical aspect)

Steps:

Enter username, password for Oracle(scott,tiger)

You will see something like this
SQL>

Start writing SQL

Create database

1)Database
SQL>create database <database name>
Eg.
SQL>create database pp
Press enter to create database

Create Table in database

2)Table
SQL>create table <table name>
Eg.
SQL>create table xx(nm varchae(5),roll varchar(5));
Table created msg displayed

Insert rows into table

3)Insert
SQL>insert into <table name>values('xx','yy');
 Enter
Eg.
SQL>insert into xx values('shobhna','001');
Enter

Msg displayed: 1 row created

SQL>insert into xx values ('cc','002');
Msg displayed: 1 row created

Similarly

SQL>insert into xx values ('dd','003');
Msg displayed: 1 row created

And so on you can insert records in table

4)Select
Select query is used to display rows in table

SQL>select * from xx;
NM              ROLL
----------------------------
Shobhna        001
cc                      002
dd                     003

5)Update

SQL>update xx set roll='005' where nm='dd';

Msg displayed: 1 row updated

SQL>select * from xx;
NM              ROLL
----------------------------
Shobhna        001
cc                      002
dd                     005->previously 003,now                                            005
6)Delete

Delete from <table name> where nm='Shobhna';

7)Drop

Drop table<table name>;
Eg.
Drop table items;