DBMS Defintion, Objective And ApplicationsDatabase: Collection
of interrelated data.example: Mark sheet and student records
DBMS: A Database Management system is a collection of
interrelated data and set of programs to access the data.
Objective of DBMS: To provide a convenient environment to
retrieve and store database information. Database systems can
support single user and multiuser environment.
Database Application: Database application is the program that
is used to view, retrieve and update information stored in the
database. The following are the few applications of Database. *
Bank database * University database * Railway database etc.,DBMS
ServicesDBMS offers following servicesData Definition: It is a
method of defining data and storage.
Data Maintaenance: It checks whether each record has field
containing information for a particular record or not.example: In
an employee table information about the employee like employee id,
name, designation, salary recorded.
Data Manipulation: It allows data in the database to be
inserted, updated, deleted and sorted.
Data Display: It helps in viewing data.
Data Integrity: It ensures the accuracy of the data.Relational
Database Management System[RDBMS]:An RDBMS is a computer program,
which provides the user the facility to store and retrieve data in
a manner consistant with a defined model called relational
model.
Relation -> table; tuple -> Row, Record;Cardinality ->
No.of rows; Attribute -> column, fieldDegree -> No.of
columns; Primary Key -> unique identifierDomain -> Set of
legal values;
Introduction to oracle9i:* Oracle9i is an Object Relational
Database Management System (ORDBMS).* It offers capabilities of
relational and object oriented database system. * Oracle products
are based on client/server technology.* In this technology server
performsall activities related to the database and the client
performs activities that help the user to interact with the
application.Features of oracle9i:* Database performance* Ease of
Management* Scalability* Security* Availability* Internet content
Management* e-commerce Integration* Packaged Applications* Business
Intelligence
Tools Of Oracle* SQL *Plus* PL/SQL* Forms* Reports
SQL *Plus: SQL *Plus is structured query language supported by
Oracle. Through SQL *Plus we can store, retrieve, edit and run SQL
commands and PL/SQL blocks. Using SQL *Plus we can perform
calculations, list column definitions for any table and can also
format query results in the form of a report.
PL/SQL: PL/SQL is an extension of SQL. PL/SQL block can contain
any number of SQL statements integrated with flow of control
statements. PL/SQL is a procedural language for the oracle server
and its client. In a PL/SQL program,SQL statements are used for
data manipulation and transaction processing.
Forms: Form is a graphical tool used for generating and
executing forms based applications. A form basically consists of
block and fields. Multiple tables can be accesed over a single
form. Oracle form builder is the design component of oracle
forms.
Reports: It is an application development tool of oracle for
developing, executing, displaying and printing reports. We can
create wide variety of reports, which have various modes. Oracle
reports are powerful and easy to use.
Oracle Data typesNUMBER:NUMBER datatype is used to store
fixed-point or floating-point numbers
We can specify precision, which is the total number of digits
and scale which is the number of digits to the right of the decimal
point.syntax: NUMBER(precision,scale)
NUMBER subtypes DEC DECIMAL INTEGER NUMERIC
CHAR:Character types allow us to store alphanumeric data,
represent words and text and manipulate character strings.
CHAR: CHAR datatype is used to store fixed-length character
data. represented internally depends on the database character set.
The CHAR datatype an optional parameter that lets us specify a
maximum length upto 32767 bytes.
syntax:char(max_length);
VARCHAR2: VARCHAR2 datatype is used to store variable-length
character data.Data represented internally depends on the database
character set. The varchar2datatype takes a required parameter that
specifies a maximum length up to 32767bytes.
syntax:varchar2(max_length);
DATE:DATE:DATE datatype is used to store fixed-length date/time
values. DATE valuesinclude the time of day in seconds since
midnight. The date portion defaults tothe first day of the current
month, the time portion defaults to midnight. THedate function
SYSDATE returns the current date and time.
Data Definition Language(DDL)The Data Definition Language is
used to create, remove and alter the structure of database objects.
The DDL is used for table definition and can be classified into 4
categories.(i) create table command(ii) alter table command(iii)
truncate table command(iv) drop table command
Data Manipulation Language(DML)Data Manipulation commands are
used to query and manipulate existing database objects. Following
are some DML commands-(i) Insert(ii) select(iii) update(iv)
delete
Data Control Language(DCL)Data Control Language is used to
control the kind of a data access to the database and transaction
control. The owner can allow other database users access to the
database objects as per his/her direction.
Eg:grant, revoke are used for data access control.commit,
rollback and save point are transaction control commands.
Creating table in OracleRules for table and column names* Names
can be upto 30 characters.* Names must begin with an alphabet.*
Names cannot contain quotes.* Names are not case sensitive.* Names
can contain characters a-z, 0-9, _, $ and #.* Names cannot be
reserve words.
Create table statement:The create table statement can be used to
create a new table.
Syntax:CREATE TABLE tablename (column1 datatype(width), column2
datatype(width), column3 datatype(width), . . column-n
datatype(width));
Example:create a table 'student' with the following
fields'Roll_no', 'Name', 'class', 'DOB' and 'Address'
CREATE TABLE student (Roll_no varchar2(20), Name varchar2(20),
class varchar2(20), DOB date, Address varchar2(100));Inserting Rows
in a tableInsert into statementThe insert into statement is used to
insert new rows into a table. we can use insert into statement in
three ways.* We can insert values into the table directly by using
the following syntax.
Syntax:INSERT INTO tablename
VALUES(value1,value2,....value-n);
Example:insert into student
values(101,'abc','BCom','03-03-90','Hyderabad');
* We can also specify the columns for which we want to insert
the data.
Syntax:INSERT INTO tablename (column1,column2)
values(value1,value2);
Example:insert into student(Roll_no, name)
values(102,'def');
* We can add fields interactively by using the following
syntax.Syntax:insert into <
values('&Roll_no','&Name','&class','&DOB','&Address');
Selecting Rows from the tableSelect statement:Select statement
can be used to view the data from the table.
We can use the select statement in the following situations.* To
view the data of only some columns in the table.* To view the data
of all columns in the table.* To view the distinct values in the
table.* select statement with where clause
* syntax To view some columns:select column-1,column-2 from
Example:select name, dob, address from student;
* Syntax to view all columns:select * from ;
Example:select * from student; [here * means all]
* Syntax to view distinct values:The distinct keyword is used to
select different values from the table.Means the distinct keyword
doesnot display the repeated data in the table.
select distinct from ;Example:select distinct name from
student;Here, repeated names wont be displayed.
* select statement with where clauseThe optional where clause
has the following syntax
where Here, the has two forms
1. exp operator exp 2. Logical Operator exp Here, operators are
=,=, logical operators are And,Or,Not
Example:select * from student where name='abc';
ConstraintsConstraints are rules that are used to control the
invalid data entry in a column. Constraints are Primary key Foreign
key Null and NotNull Unique Check DefaultPrimary KeyThe primary key
has two features1. It defines the column as manadatory i.e column
cannot be left blank.2. The data held across the column must be
unique i.e values should not be repeated.
* A single column primary key is known as simple primary key.*
Multi column primary key is known as composite primary key.
Note: We cannot define more than one primary key in a single
table. We can define primary key for multi columns by using
composite primary key.
Example on simple primary key:create a table 'customer' with the
following fieldscust_no as primary key, name, address, city, state,
pin.
create table customer(cust_no number(10) primary key, name
varchar2(50), address varchar2(50), city varchar2(50), state
varchar2(50), pin number(6));
Example on composite primary key:create table product(order_no
number(10), prod_no varchar2(20), qty number(5), price number(8,3)
primary key(order_no,prod_no));
Null:If in a record any field that is created as nullable(not
having value) then oracle will replace a null value in that column.
Null value is not equivalent to zero or blank. Null values can be
inserted into the columns of any datatype.
Not Null:The not null constraint ensures that the users always
type the value for that column becomes a manadatory column. Not
null constraint can be applied at column level only.Unique Key*
unique key constraint ensures that information in the columns is
unique i.e value entered in unique column must not be repeated
across the column(s).
* A table may have more than one unique key. Unique key may be
null at the time of data entry. So, value is not manadatory in
unique key column.
* We can define a single column as unique and not null both then
the constraint will work as primary key.
CheckCheck constraint ensure that when data is entered, the data
in the column is limited to specific values.eg: category
varchar2(5) check(category in ('sc','st'));Default Constraint:At
the time of table creation a default value can be assigned to a
column. When the user is entering the values and leaves this column
empty the oracle will auotmatically load this column with the
default value. The datatype of the default value should match the
datatype of the column.
eg: age number(3) default 21;
Update StatementThe update statement is used to update or change
records that match a specified criteria. This is accomplished by
carefully constructing a where clause.
syntax: update set columnname=newvalue,
columnname1=newvalue1,... where
eg: update employee set phoneno='9884532245' where
ename='abc';
AlterThe ALTER command is used to modify the structure of a
table. Using ALTER command, we can add new columns, modify existing
columns, and add or drop integrity constraints.
ALTER can be used to make the following changes to any tables*
Add new columns* Add new integrity constraints* Modifying existing
columns -Expand length -Change default -Decrease length -All values
in column must be null -Change data type -All values in column must
be null* Drop integrity Constraints
Alter SyntaxesTo add a new columnsyntax: alter table
add(new_colname datatype(width));example: alter table employee
add(address varchar2(10));
To change the width of the exisiting fieldsyntax: alter table
modify(col_name datatype(width));example: alter table employee
modify(address varchar2(50));
To rename the columnsyntax: alter table rename column old_col to
new_col;example: alter table employee rename empname to
employename;
Adding Many columns in a single alter statementsyntax: alter
table add(col1 datatype(width), col2 datatype(width).. coln
datatype(width));example: alter table employee add(address
varchar2(20), city varchar2(20), dob date);
To add a primary keysyntax: alter table add primary
key(field);example: alter table employee add primary
key(empno);
To remove a primary keysyntax:alter table drop primary
key;example:alter table employee drop primary key;
employee table1. Create a table 'employee' with the following
fieldsEmpnovarchar26(primary key) Enamevarchar220(not
null)Jobchar10Hiredatedate basic_salnumber (9,2)commnumber
(7,2)dept_novarchar2 2
Q: create table employee(empno varchar2(6) primary key, ename
varchar2(20) not null, job char(10), hiredate date, basic_sal
number(9,2), comm number(7,2), dept_no varchar2(2));
2. Describe the table 'employee'Q: desc employee
3. Insert the following data into the above 'employee'
tableempnoenamejobhiredatebasic_salcommdept_no
E0001kimManager15-dec-025000500D001
E0002BruceAnalyst24-Apr-994000400D002
E0003ArnoldClerk10-jan-012500250D004
E0004HolyfieldTester10-oct-013000300D002
E0005kellyAdmin11-apr-992000200D003
Q: insert into employee values('E0001','Kim','Manager',
'15-Dec-02','5000.00','500','D001'); insert into employee
values('E0002','Bruce','Analyst', '24-Apr-99','4000','400','D002');
insert into employee values('E0003','Arnold','Clerk',
'10-jan-01','2500','250','D004'); insert into employee
values('E0004','Holyfield','Tester',
'10-oct-01','3000','300','D002'); insert into employee
values('E0005','Kelly','Admin',
'11-Apr-99','2000','200','D003');
Select Command And Like OperatorI. employee table1. List the
names of the employee who have a salary less than Rs.3000 from
employee tableQ. select ename from employee where basic_sal <
3000
3. List all the employees whose name starts with the letter 'K'
from employee table.Q. select ename from employee where ename like
'K%';
4. List the employee name working in department D002, D003 from
employee table.Q. select ename from employee where dept_no='D002'
or dept_no='D003';
5. List all employee whose name start with 'A' and end with 'd'
from employee table.Q. select ename from employee where ename like
'A%d';
6. List all managers and salesman with salary over 2500 from
employee table.Q. select ename from employee where (job='Manager'
or job='Sales man') and basic_sal>2500;
7. Display all the employee names in the ascending order of
their date of joining from employee table.Q. select ename from
employee order by hiredate asc;
8. Display all the employees in alphabetical order from employee
table.Q. select ename from employee order by ename;
9. List all employee who where hired during 1999 from employee
table.Q. select ename from employee where
to_char(hiredate,'yy')=99;
10. List all employees whose commission is more than Rs.300 from
employee table.Q. select ename from employee where comm>300;
II. client_mast table 1. Find out the names of all the clients
from client_mast table. Q. select name from client_mast;
2. Retrieve all the records from client_mast table Q. select *
from client_mast;
3. Retrieve all the list of names, address and city of all the
clients from client_mast Q. select name,address,city from
client_mast;
4. List all the clients who are staying in Florida from
client_mast table Q. select name from client_mast where
state="Florida";
III. Dept table 1. List the department name which is located in
Noida and Rockey Creek from Dept table. Q. select dname from
depttable where loc='Noida' or loc='Rocky Creek';
Update CommandI. employee table1. Change the basic salary
Rs.3000 where basic salary less than 2500 from employee table Q.
update employee set basic_sal=3000 where basic_sal editDeclare a
number; b number; c number;Begin a:=&a; b:=&b; c:=&c;
if a>b and a>c then dbms_output.put_line(a||'is greater');
elsif b>a and b>c then dbms_output.put_line(b||'is greater');
elsif c>a and c>b then dbms_output.put_line(c||'is greater');
end if; end;SQL> /Program to calculate Factorial of
number.declarev_num number :=#fact number :=1;beginfor i in
1..v_numloopfact:=fact*i;end loop;dbms_output.put_line('fact of
'||v_num||' is '||fact);end;/
Program to calculate Even or odd Numberdeclaren number;r number
:=1;beginn:=&number;for r in 1..nloopif mod(r,2)=0
thendbms_output.put_line('Even No :' || r);end if;end loop;end;
Multiplication TableDECLAREn number := &n;prod
number;BEGINfor i in 1..10 loop prod := n * i;
dbms_output.put_line(n||' * '||lpad(i,2,' ')||' = '||lpad(prod,3,'
'));end loop;END;
Types of Table RelationshipsA relationship works by matching
data in columns usually columns with the same name in both tables.
In most cases, the relationship matches the primary key from one
table, which provides a unique identifier for each row, with an
entry in the foreign key in the other table.
There are three types of relationships between tables.
One-to-Many Relationship Many-to-Many Relationships One-to-One
Relationships
One-to-Many RelationshipsA one-to-many relationship is the most
common type of relationship, a row in table A can have many
matching rows in table B, but a row in table B can have only one
matching row in table A. For example, the publishersandtitlestables
have a one-to-many relationship: each publisher produces many
titles, but each title comes from only one publisher.
Many-to-Many RelationshipsIn a many-to-many relationship, a row
in table A can have many matching rows in table B, and vice versa.
You create such a relationship by defining a third table, called a
junction table, whose primary key consists of the foreign keys from
both table A and table B.
One-to-One RelationshipsIn a one-to-one relationship, a row in
table A can have no more than one matching row in table B, and vice
versa. A one-to-one relationship is created if both of the related
columns are primary keys or have unique constraints.
One-to-one relationships: This relationship exists where a
record in Table A can only have one related record in Table B, and
a record in Table B can only have a single matching record in Table
A For example, an MP can have only one constituency, and a
constituency can have only one MP
One-to-many relationships: This relationship exists where a
record in Table A can have no, one or more matching record in Table
B, but a record in Table B can only have one matching records in
Table A For example, a mother can have more than one child, but a
child can have only one biological mother
Many-to-many relationships: This relationship exists where a
record in Table A can have no, one or many matching records in
Table B, and a record in Table B can have no, one or more than one
matching record in Table A For example, an author can write more
than one book and a book can be written by more than one author
