ORACLE

Using ORACLE 8

SQL using ORACLE 8

PL/SQL using ORACLE 8

SQL Data Types

• Numeric Data Types

• String Data Types

• Data/Time Data Types

SQL Data Types (Numeric)

• INTEGER signed integer 31 bits

• SMALLINT signed integer 15 bits

• DECIMAL(p, q)signed number p digits, q decimals

• FLOAT(p) floating point number, p bits precision

SQL Data Types (String)

• CHAR(n) fixed length string, of n-8 bits

• VARCHAR(n) varying length string, up to n-8 bits

• GRAPHIC(n) fixed length string, n-16 bits

• VARGRAPHIC(n) varying length string n-16 bits

SQL Data Types (Date/Time)

• DATE date (yyyy-mmm-dd)

• TIME time (hh:mm:ss)

• TIMESTAMP combination of date and time

Basic Table Level Operations

• Creation: Using the create command• Populating tables: Entering values into the table using

the insert command• Modifying data: Modifying data in the tables using the

update command• Deleting data: Deleting data from tables using the delete

command• Altering tables: Using the alter command• Deleting tables: Deleting tables using the drop command

Creating Tables

create table <table_name>

(

<column1> <datatype> [constraint],

<column2> <datatype> [constraint],

… … …

);

Example using “create”

create table CD_MASTER

(

CD_NO number

CONSTRAINT pk_cd PRIMARY KEY,

CD_NAME varchar2(25),

ARTIST varchar2(25),

TYPE varchar2(15)

);

Inserting Data

insert into <table_name>

(first_column, second_column, … last_column)

values (first_value, second_value, … );

Example using “insert”

insert into CD_MASTER values (101, ‘Fields of Gold’, ‘Sting’, ‘Rock’);

insert into CD_MASTER values(102, ‘Supernatural’, ‘Santana’, ‘Rock’);

insert into CD_MASTER values (103, ‘Division Bell’, ‘Pink Floyd’, ‘Rock’);

Modifying data

update <table_name>

set <column_name> = <new_value>

where <condition>;

Deleting Data

delete from <table_name>

where <SQL_condition>;

Altering table definitions

alter table <table_name>

add | drop | modify

(<column specification[s]>);

Deleting tables

drop table <table_name>

[cascade constraints];

Alternate way of data entry

Create tables from using the an SQL command (.SQL) file. Specify all the table definitions & constraints.

Create a “control” file (.CTL), giving specific instructions on interpreting a certain data file

List out all data in the data file

The SQL command file

• Specify the exact SQL commands for creating tables using the create statement, exactly the same way as on the SQL prompt

• Drop a table before creating it

The Control File

Structure:

load data

infile <name of data file in single quotes>

into table <table name>

fields terminated by ',' optionally enclosed by '"'

(<field1>, <field2>, … , <last_field>)

Example control file

• (save this in cdmaster.ctl)

load data

infile ‘cdmaster.dat’

into table CD_MASTER

fields terminated by ',' optionally enclosed by '"'

(CD_NO, CD_NAME, ARTIST, TYPE)

The Data File

• field1_val1, field2_val1, …

• field1_val2, field2_val2, …

• field1_val3, field2_val3, …

• field1_val4, field2_val4, …

• field1_val5, field2_val5, …

• … … ...

Example data file

• (save this in cdmaster.dat)

101,‘Fields of Gold’,‘Sting’,‘Rock’

102,‘Supernatural’,‘Santana’,‘Rock’

103,‘Division Bell’,‘Pink Floyd’,‘Rock’

104,'ABBA Gold','ABBA','Pop'

105,'Unconditional','Classy Davidson','Country'

Running the scripts

• telnet to zaurak.cis.ksu.edu

• sqlplus name/password @<create.sql>– creates the tables in SQL

• sqlldr name/password control=<ctrlfile.ctl>– populates the table specified in ctrlfile.ctl– Note: The filename should not be in quotes

Useful commands

• / : Executes the previous command

• ed: Opens edit buffer for typing in and modifying commands

• help: Online ORACLE help

• password: To change the user’s password

The Spooler

• Syntax:SPOOL [OFF | <filename>]

• e.g. spool a.spl– saves the screen display into a file a.spl

• e.g. spool off– turns off the spooler

Useful ORACLE-SQL commands

• DESCRIBE: Shows the structure of a database table

• Syntax:

describe <table_name>;

can be shortened to

desc <table_name>;

The system table “tab”

• tab: It’s the table of tables, i.e. stores the names of all the tables created by the user

• select * from tab;– lists all the tables created

The system table ALL_OBJECTS

• Stores details of all the tables created by all the users on the system.

• select OWNER from ALL_OBJECTS;– lists all the owners on the system

• select OBJECT_NAME from ALL_OBJECTS where owner=‘NJAGAN’– lists all tables owned by user “NJAGAN”

The system table ALL_USERS

• Keeps information of all the user accounts created on the system

• Structure:– <USERNAME, USER_ID, CREATED>

• e.g. select * from ALL_USERS– lists all the users who hold accounts on the

ORACLE server

Granting privileges

• GRANT – Grants a privilege to a user– Can grant privilege only if you have been

granted that privilege (or if you are the administrator)

grant <privilege> to <user>;

Examples of granting roles

• grant create table to john;

• grant all on CD_MASTER to tom;

• grant SELECT ON CD_MASTER.CD_NAME to john;

• grant select, update on CD_DB to tom;

• grant references(CD_NO) on CD_DB to john;

Revoking roles

• REVOKE – Revokes a privilege from a user– Can revoke privilege only if you have been

granted that privilege (or if you are the administrator)

revoke <privilege> from <user>;

Examples of revoking roles

• revoke DROP ANY TABLE from tom, john;

• revoke DELETE on CD_NAME from tom;

• revoke references on CD_MASTER.CD_NO from tom;

Stored Procedures

• a group of PL/SQL statements that you can call by name

• must have CREATE PROCEDURE system privilege

Syntax of stored procedures

create procedure

<schema_name>.<proc_name> (parameters…)

as begin

… <body of stored procedure> …

end;

Example of a stored procedure

CREATE PROCEDURE sam.credit (acc_no IN NUMBER, amount IN NUMBER)

AS BEGIN UPDATE accounts

SET balance = balance + amount WHERE account_id = acc_no;

END;

Triggers

• Stored procedure associated with a database table

• Automatically fired when the specified trigger condition is satisfied

Trigger Conditional Predicates

• INSERTING

• DELETING

• UPDATING

• UPDATING (column_name)

Types of Triggers

Trigger

BEFORE AFTER

FOR EACH ROW

Trigger Structure

• create trigger <trigger_name>[before | after] [insert | update | delete]

on <table_name> [for each row]

begin

… <trigger_body> …

end;

Uses of Triggers

• to provide sophisticated auditing and transparent event logging

• to automatically generate derived column values

• to enforce security

• to maintain replicate tables

Event logging trigger

CREATE TRIGGER audit_trigger

BEFORE INSERT OR DELETE OR UPDATE

ON classified_table FOR EACH ROW

BEGIN

IF INSERTING THENINSERT INTO audit_table VALUES (USER || ' is

inserting' || ' new key: ' || :new.key);

END IF;

END;

Views

• logical table that contains data from other tables and views

• no extra storage space

• restrict access to predetermined sets of rows/columns

• updateable

• essentially results of a query

Syntax for creating views

• create view <view_name> as<SQL Query>;

Example:

create view CD_LIST as

select CD_NAME, CD_ARTIST from CD_MASTER;

Database Computing

Database Computing

Thin Client / Thick Server

Thick Client / Thin Server