Rdbms Lab File

7/29/2019 Rdbms Lab File

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INDEX

Queries:

1. CREATE TABLE

2. INSERT

3. ALTER TABLE

a. ADD COLUMN

b. MODIFY COLUMN

c. DROP COLUMN

4. UPDATE

5. DROP TABLE

6. DELETE

7. TRUNCATE TABLE

8. LIKE and NOT LIKE

9. IN and NOT IN

10.ORDER BY

11.Primary Key

12.Foreign Key

13.GROUP BY

Experiments:

1. To write the queries for the retrieval of required data from the given tables.

2. To write a program in PL/SQL to print a string of characters.

3. To write a program in PL/SQL to add two pre-defined numbers.4. To write a program in PL/SQL to add two numbers which are taken as inputs from the

user.

5. To write a program in PL/SQL to subtract two numbers which are taken as inputs from

the user.

6. To write a program in PL/SQL to multiply two numbers which are taken as inputs from

the user.

7. To write a program in PL/SQL to divide two numbers which are taken as inputs from the

user.


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'Create Table' Query

Description:

The CREATE TABLE command is used to specify a new relation by giving it a name and

specifying its attributes and constraints. The attributes are specified first, and each attribute is

given a name, a data type to specify its domain of values, and any attribute constraints such as

NOT NULL. The key, entity integrity, and referential integrity constraints can be specified

within the CREATE TABLE statementafter the attributes are declared.

Syntax:

create tabletablename

(

attributename1 datatype(range) constraint1 constraint2,

attributename2datatype(range),

attributename3 datatype(range) constraint,

);


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Example:


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'Insert' Query

Description:

In its simplest form, INSERT is used to add a single tuple to a relation. We must specify the

relation name and a list of values for the tuple. The values should be listed in the same orderin

which the corresponding attributes were specified in the CREATE TABLE command.

A second form of the INSERT statement allows the user to specify explicit attribute names that

correspond to the values provided in the INSERT command. This is useful if a relation has

many attributes, but only a few of those attributes are assigned values in the new tuple.

Another form of INSERT command allows us to insert the values of a new tuple in the format of

a form. This type of INSERT query is executed using the '&' sign. The syntax of this type of

query is stated below.

Syntax:

INSERT without &:

insert intotablename(attriibute1, attribute2, ) values(value1, value2, value3, );

INSERT with &:

insert intotablename(attriibute1, attribute2, ) values(&attribute1, &attribute 2, &attribute3, );


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Example:

INSERT without '&':


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INSERT with '&':


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'Alter Table' Query

Description:

The definition of a base table can be changed by using the ALTER TABLE command, which is a

schema evolution command. The possible alter table actions include adding or dropping a

column (attribute), changing a column definition, and adding or dropping table constraints. It isalso possible to alter a column definition by dropping an existing default clause or by defining a

new default clause. Also, one can change the constraints specified on a table by adding or

dropping a constraint. To be dropped, a constraint must have been given a name when it was

specified.

Syntax:

Add Column:

alter tabletablename add (attributename datatype(range) constraint);

Modify Column:

alter tabletablename modify (attributename datatype(range));

Drop Column:

alter tabletablename drop column attributename;


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Example:

Add Column:


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Modify Column:


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Drop Column:


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'Update' Query

Description:

The UPDATEcommand is used to modify attribute values of one or more selected tuples. A

WHERE-clause in the UPDATE command selects the tuples to be modified from a single

relation. However, updating a primary key value may propagate to the foreign key values of

tuples in other relations if such a referential triggered action is specified in the referential

integrity constraints of the DDL. An additional SET-clause specifies the attributes to be modified

and their new values.

Syntax:

update tablename set attributename1 = value1, attributename2= value2 where attributename =value3;


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Example:

Before Updating:


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After Updating:


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'Drop Table' Query

Description:

If a base relation within a schema is not needed any longer, the relation and its definition can be

deleted by using the DROP TABLE command.

If the RESTRICT option is chosen instead of CASCADE, a table is dropped only if it is not

referenced in any constraints (for example, by foreign key definitions in another relation) or

views. With the CASCADE option, all such constraints and views that reference the table are

dropped automatically from the schema, along with the table itself. The RESTRICT option is the

default option for the DROP TABLE command.

Syntax:

drop tabletablename;


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Example:


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'Delete' Query

Description:

The DELETE command removes tuples from a relation. It includes a WHERE-clause to select

the tuples to be deleted.

Tuples are explicitly deleted from only one table at a time. However, the deletion may propagate

to tuples in other relations if referential triggered actions are specified in the referential integrity

constraints of the DDL.

Depending on the number of tuples selected by the condition in the WHERE-clause, zero, one,

or several tuples can be deleted by a single DELETE command. A missing WHERE-clause

specifies that all tuples in the relation are to be deleted; however, the table remains in the

database as an empty table.

Syntax:

Delete from tablename where attributename = value;


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Example:

Before Deletion:


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After Deletion:


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'Truncate Table' Query

Description:

The TRUNCATE TABLE command is used to delete all the data of the table while retaining the

structure of the table.

Syntax:

truncate tabletablename;


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Example:


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'Like' and 'Not Like' Queries

Description:

A feature of the SELECT query allows comparison conditions on only parts of a character string,

using the LIKE comparison operator. Partial strings are specified by using two reserved

characters: % replaces an arbitrary number of characters, and the underscore ( _ ) replaces a

single character. All the values that satisfy the LIKE condition in the given columns of the table

are retrieved and displayed.

NOT LIKE comparison operator is an exact opposite of the LIKE operator. It helps in retrieval of

all the values in the given columns of the table which don't satisfy the condition specified in theNOT LIKE operator.

Syntax:

Like:

select colname1, colname2, fromtablename where attribute1 like %constant%;

Not Like:

select colname1, colname2, fromtablename where attribute1 not like %constant%;


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Example:

Like:


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Not Like:


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'IN' and 'Not IN' Queries

Description:

The comparison operator IN compares a value v with a set (or multiset) of values V and

evaluates to TRUEif v is one of the elements in V. The IN operator can also compare a tuple of

values in parentheses with a set or multiset of union-compatible tuples. It retrieves all the values

that satisfy the IN condition.

NOT IN comparison operator is an exact opposite of the IN operator. It helps in retrieval of all

the values which don't satisfy the condition specified in the NOT IN operator.

Syntax:

IN:

select colname1, colname2, fromtablename where attribute1 in (value1, value2);

Not IN:

select colname1, colname2, fromtablename where attribute1 not in (value1, value2);


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Example:

IN:


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Not IN:


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'Order By' Query

Description:

SQL allows the user to order the tuples in the result of a query by the values of one or more

attributes, using the ORDER BY-clause.The default order is in ascending order of values. Wecan specify the keyword DESC if we want a descending order of values. The keyword ASC can

be used to specify ascending order explicitly.

Syntax:

Ascending Order:

select colname1, colname2, fromtablename where attribute1 = value1, attribute2= value2order by attribute asc;

Descending Order:

select colname1, colname2, fromtablename where attribute1 = value1, attribute2= value2order by attribute desc;


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Example:

Ascending Order:


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Descending Order:


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Primary Key

Description:

It is common to designate one of the columns in the relation as the PRIMARY KEY of the

relation. This is the column whose values are used to identifytuples in the relation.

The ENTITY INTEGRITY CONSTRAINTstates that no primary key value can be null and must

be unique. This is because the primary key value is used to identify individual tuples in a

relation; having null values or repeating values for the primary key implies that we cannot

identify some tuples.

Syntax:


(



attributename3 datatype(range) constraint

primary key (attributename1, attributename2)

);


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Example:


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Foreign Key

Description:

The conditions for a foreign key specify a referential integrity constraint between the two relation

schemas R1 and R2. A set of attributes FK in relation schema R1 is a foreign key of R1 that

references relation R2 if it satisfies the following two rules:

1. The attributes in FK have the same domain(s) as the primary key attributes PK of R2; the

attributes FK are said to reference or refer to the relation R2.

2. A value of FK in a tuple t1 of the current state r1(R1) either occurs as a value of PK for some

tuple t2 in the current state r2(R2) or is null. In the former case, we have t1[FK] = t2[PK], and we

say that the tuple t1 references or refers to the tuple t2. R1 is called the referencing relation and

R2 is the referenced relation.

A foreign key can refer to its own relation. For example, the attribute SUPERSSN in

EMPLOYEE refers to the supervisor of an employee; this is another employee, represented by

a tuple in the EMPLOYEE relation. Hence, SUPERSSN is a foreign key that references the

EMPLOYEE relation itself.

Syntax:


(



attributename3 datatype(range) constraint

foreign key (attributename1) references tablename(attributename));


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Example:


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'Group By' Query

Description:

The GROUP-BY clause is used in conjunction with the SELECT query. The GROUP BY-clause

specifies the grouping attributes, which should also appear in the SELECT-clause, so that the

value resulting from applying each function to a group of tuples appears along with the value of

the grouping attribute(s).

Syntax:

select colname1, colname2, fromtablename where attribute1 = value1, attribute2= value2

group by attribute;


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Experiment 1

Aim:

To write the queries for the retrieval of required data from the given tables.

Tables:

Works (p_name, c_name, salary);

Lives (p_name, street, city);

Located_in (c_name, city);

Managers (p_name, m_name) ;

Queries:

1. To select names of the people who work for First Bank Corporation :

select p_name from works where c_name = First Bank Corporation ;

2. To select names and cities of residence of the people who work for First Bank

Corporation :

select works.p_name, lives.city from works, lives where c_name = First Bank

Corporation and works.p_name = lives.p_name ;

3. To select names and address of residence of the people who work for First Bank

Corporation and earn more than 10000 :

select works.p_name, lives.street, lives.city from works, lives where c_name = First

Bank Corporation and salary > 10000 and works.p_name = lives.p_name ;

4. To select names of the people who reside in the same city in which they work :

select lives.p_name from works, lives, located_in where lives.city = located_in.city and

works.p_name = lives.p_name and works.c_name = located_in.c_name ;

5. To select names of the people who do not work for First Bank Corporation :

select p_name from works where p_name not in (select p_name from works where

c_name = First Bank Corporation) ;


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6. To select names of the people whose salary is more than the salary of every employee

working for Second Bank Corporation :

select p_name from works where salary > all(select salary from works where c_name =

Second Bank Corporation) ;


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Experiment 2

Aim:

To write a program in PL/SQL to print a string of characters.

Program:

set serveroutput on

begin

dbms_output.print_line(Hello);

end;

Output:

HelloPL/SQL procedure successfully completed.


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Experiment 3

Aim:

To write a program in PL/SQL to add two pre-defined numbers.

Program:

set serveroutput on

declare

num1 number := 30;

num2 number := 20;

num3 number;

begin

num3 = num1 + num2;

dbms_output.print_line(Sum is: || num3);

end;

Output:

Sum is: 50PL/SQL procedure successfully completed.


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Experiment 4

Aim:

To write a program in PL/SQL to add two numbers which are taken as inputs from the user.

Program:

set serveroutput on

declare

num1 number := &num1;


num3 number;

begin

num3 = num1 + num2;

dbms_output.print_line(Sum is: || num3);

end;

Output:

num1 = 30num2 = 20

Sum is: 50PL/SQL procedure successfully completed.


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Experiment 5

Aim:

To write a program in PL/SQL to subtract two numbers which are taken as inputs from the user.

Program:

set serveroutput on

declare



num3 number;

begin

num3 = num1 - num2;

dbms_output.print_line(Difference is: || num3);

end;

Output:

num1 = 30num2 = 20

Difference is: 10PL/SQL procedure successfully completed.


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Experiment 6

Aim:

To write a program in PL/SQL to multiply two numbers which are taken as inputs from the user.

Program:

set serveroutput on

declare



num3 number;

begin

num3 = num1 * num2;

dbms_output.print_line(Product is: || num3);

end;

Output:

num1 = 30num2 = 2

Product is: 60PL/SQL procedure successfully completed.


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Experiment 7

Aim:

To write a program in PL/SQL to divide two numbers which are taken as inputs from the user.

Program:

set serveroutput on

declare



num3 number;

begin

num3 = num1 / num2;

dbms_output.print_line(Quotient is: || num3);

end;

Output:

num1 = 30num2 = 2

Quotient is: 15PL/SQL procedure successfully completed.

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Rdbms Lab File