dbms-lab-

DBMS Department of Computer Science Data Base Management Systems Laboratory Manual

Data Base Management System lab manual

CONTENTS

1. Creating tables for various relations.

2. Implementing the queries in SQL fora) Insertion.b) Retrieval.c) Updation.d) Deletion.

3. SQL Reporting.

4. Creating views.

5. Introduction to pl/sqlImplementing operations on relations.

6. Writing Cursors.

7. Exception handling.

8. Writing function.

9. Writing procedure

10. Writing package.

11. Writing Triggers.

12. Creating Forms and Generating Reports

1


Introduction to Database Management System

All database management systems (oracle is a DBMS) allows users to create containers for data storage and management. These containers are called ‘cells’. The minimum information that has to be given to oracle for suitable container to be constructed which can hold free form human data is

The cell/field name The cell/field length The type of data that can be placed in to the cell.

We imagine that each field was an object created for us by oracle. Then number of fields created in same horizontal plane would be another object created for us by oracle. Multiple fields placed in the same horizontal plane is an object called a Record by oracle. Several ‘Records’, of equal length, placed one below the other to enable users to continue to store data is called a ’Table’(consists of rows and columns used for storing data).

The table therefore becomes the third object after fields and rows.

A GROUP of ‘Tables’ with ‘related’ data in them is called a ’database’.

Relational data base management system

Relational data base management system uses only its relational capabilities to manage the information stored in its database.

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Introduction to SQL

SQL stands for Structured Query Language. Oracle provides many extensions to ANSI SQL.SQL is standard language for interfacing with a relational database.

A table is primary database object of SQL ,which is used to store the data in the form of rows and columns. SQL developed by IBM is used as standard language to access data from database. In order to communicate with database SQL has been divided into three sub languages and each sub language consists of different commands, they are

a) Data Definition LanguageDDL COMMANDS:

CREATEALTERDROP

b) Data Manipulation LanguageDML COMMANDS:

SELECTINSERTUPDATEDELETE

c) Transaction Commit Language

TCL COMMANDS:COMMITROLLBACKSAVEPOINT

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EXERCISE -1

DATA TYPES

In order to create a data base object (table) we need to specify a data type of that particular columns while creation of that table itself. Oracle mainly supports two types of data types.

1. Internal data type.2. Composite data type.

A data type associates a fixed set of properties with the values that can be used in a column of a table or in an argument of a procedure or function. These properties cause oracle to treat values of one data type different from values of another data type.

Oracle supplies the following built-in data types:

CHARACTER DATATYPES Char(size)

Fixed-length character data of length size bytes(maximum 2000 bytes per row ,default size is 1 byte per row).

Varchar2(size)variable length character data.

NUMBER DATATYPE

Number(p,s)

Variable-length numeric data (fixed or floating point).

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DATE DATATYPE

Date Fixed length date and time date.The standard format is dd-mon-yy.To enter dates other than standard format ,use the appropriate functions.

LONG DATATYPE

Long

Cell/field defined as LONG can store variable length character strings containing upto 65,535 characters.

USER DEFINE DATATYPES:

Like the oracle internal data types that are already present the user can create new data type.

When we define the data type we use create or replace command.

SYNTAX: for creating a table

create table <table name>(columnname data type(size),columnname datatype(size));

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For example: create a table which describes employee particulars.

cccccccol

Its code is as followed

SQL> CREATE TABLE employee(empname varchar2(20),emp no. varchar2(6),address varchar2(30),pin code number(6),salary number(10,2));

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Column name data type size

empname varchar2 20emp no. varchar2 6Address varchar 30Pin code number 6Salary number 10,2


CONSTRAINTS

Constrains are the mechanism used in oracle in order to prevent invalid data or to avoid the duplicacy of the data being entered by the user.

Integrity constraints:

An integrity constraint is the rule that restricts the values for one or more columns in a table.

Constraint clauses can appear in either CREATE TABLE or ALTER TABLE commands.

SYNTAX to define an integrity constraint ,

Table_constraint::= create table <table_name>(column_name datatype , column_name datatype ,constraint constraint_name constraint_definition (column_names));

NOTE: This syntax can define any type of integrity constraint except a NOT NULL constraint.

Column_constraint::= create table <table_name>(column_name datatype ,constraint constraint_specification);

NOTE: Column_constraint table that appears in an ALTER Table statement can only define or remove a NOT NULL constraint.

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There are three types of constraints

1. Domain Integrity Constraint.

Not Null Constraint

Syntax:create table <table_name>

(column_name datatype Not Null);

Check constraint

Syntax:create table <table_name>

(column_name datatype check <condition>);

2. Entity Integrity Constraint.

Unique_constrain

syntax:

create table <table_name>(column definitions ,constraint [constraint-name] unique);

Primary key

syntax:

create table <table_name>(column definitons ,<constraint> [constraint-name] primary key);

Note: The DISABLE option oracle to define the constraint but not enforce it.

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3. Referential Integrity Constraint.

Syntax:

create table <table_name>(column definitons ,<constraint> [constraint-name] reference <parents table_name>< column_name>);

4. Foreign key

This identifies the column or combination of columns in the child table that makes up of the foreign key .

On Delete Cascade

Allows deletion of referenced key values in the parent table that have dependent rows in the child table and causes oracle to automatically delete dependent rows from the child table to maintain referential integrity.

Syntax:

create table <table_name>(column definitons ,<constraint> [constraint-name] reference <parents table_name>< column_name>);

create the following tables with the help of above example..

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TABLE STRUCTURE FOR DBMS LAB

I DEPARTMENT:DCODE numberDNAME varchar2

II EMPLOYEE:ECODE numberENAME varchar2GCODE varchar2DOB dateDOJ dateDCODE numberSEX charBASIC numberREPORTTO number (Same as ecode)

III PROGRAME:PCODE varchar2ECODE number

IV PROGSEC:PCODE varchar2PNAME varchar2DURATION numberDESCRIPTION varchar2

V GRADE:GCODE varchar2GNAME varchar2MAXBASIC numberMINBASIC numberRAISE number

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Exercise -2

BASIC CLAUSES IN SQL:

SELECT colum1,colum2[,column3,....]

this clause is used to diplay selected columns.

FROM table1[,table2,....]

this clause is used to select the source tables.

OPTIONAL CLAUSES:

WHERE condition1 [and condition2 [or condition3]]

this clause is used to give some condition which can be imposed on selected columns.

ORDER BY column1[,column2,...] [desc]

this clause is used to get the result in sorting orderof columns specified in the same clause.

GROUP BY column1,column2

Whenever you want to select column name along with group funcitons you should include those columns in group by clause. group by clause can also have not selected columns.

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HAVING condition.

This cluase should preceded by group by clause. We use this to give column selection conditions which cannot be achieved by

where clause(row selection condition).

The following in built functions in oracle are just a few selected from many functions that are most commonly used in commercial

application development.

DUAL is a table which consists single column and single row.using this usually we will check the funcitons.

PSEUDO COLUMNS:

ROWNUM, ROWID, LEVEL, SYSDATE

AGGREGATE OR GROUP FUNCTIONS :

AVG, MAX, MIN, SUM, COUNT

NUMBER FUNCTIONS :

ABS,POWER,ROUND,SQRT.

STRING FUNCTIONS:

LOWER, UPPER, INITCAP, SUBSTR, LENGTH, LTRIM, RTRIM,LPAD, RPAD

DATE FUNCTIONS :

ADD_MONTHS, MONTHS_BETWEEN, NEXT_DAY, LAST_DAY

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CONVERSION FUNCTIONS:TO_CHAR, TO_DATE, TO_NUMBER

MISLENIOUS FUNCITONS: DECODE, TRANSLATE.

Note: For the detailed information of above mentioned functions refer to complete reference Or sql/pl/sql by Oracle press

write the following queries

Exercise-2(A)1. Insert values into your table for specific columns.2. Insert values into your table for all columns.3. Insert values into one table using other table.

Exercise-2(B)

1. Select specific columns from a table.2. Select distinct columns from a table.3. Select specific columns by changing column headings.4. Select today's date using dual table.

Exercise-2(C)1. Update a single column value in a table.2. Update more than one column value in a table.

Exercise-2(D)

1. Delete all rows from a table.2. Delete specific rows from a table.

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JOINS

Introduction to Joins different or same tables(is done using concept called JOINS):

Examples are shown below which covers different types of joins.

1. NORMAL JOIN

CARTISIAN PRODUCTSELECT * FROM EMP,DEPT

2. EQUI JOIN & NON EQUI JOIN

SELECT * FROM EMP, DEPT WHERE EMP.DEPTNO=DEPT.DEPTNO

SELECT * FROM EMP, DEPT WHERE EMP.DEPTNO<>DEPT.DEPTNO

3. SELF JOIN

SELECT EMPNO,MGRFROM EMP A, EMP BWHERE A.EMPNO=B.MGR

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4. OUTER JOIN

LEFT OUTER JOIN RIGHT INNER JOIN

SELECT EMPNO,ENAME FROM EMP, DEPTWHERE EMP.DEPTNO(+)=DEPT.DEPTNO

SELECT EMPNO,ENAME FROM EMP, DEPTWHERE EMP.DEPTNO=DEPT.DEPTNO(+)

Write the following queries.

1. Get a list of all employees in a particular department along with their gradecode, grade description, current basic and maximum basicin current grade.apply lpad to gcode to get like

g1--------------------- in total 35 characters along with gcode.

lpad(string,total no of characters,format)

2. Get list of all employees who had attended a particular training program. Get the program code at runtime.

3. Get list of all employees in a particular age group. Specify the age group like 22-30 yrs (hint:months_between).

4. Get the list of all employees whose first letters of the names have been specified.

5. Get the number of employees,and average basic in each department for every grade.

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Exerice:3

SQL REPORTING:

EXAMPLE:Q: To get the list of all employees in their of order of employee names

REM first programe.SET HEADSEP *SET FEEDBACK offSET NEWPAGE 2TTITLE 'Solution to the first query * list of all employees'BTITLE 'CMRCET'COLUMN ename HEADING 'Employees * Name' format a10SET PAGESIZE 24select ename from emp order by ename desc;SET PAUSE 'more...'set pause on

Output:

Solution to the first query list of all employees

EmployeesName......

CMRCET

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Generate SQL Report for the following queries using above sql report commands

1. Get the list of all employees in reverse order of employee code,display ecode as Employee ,dcode as Employee , ename as Employee

Code Department Name

2. Get the gname at runtime and give the following report remset headsepset feedback ttitle btitlecolumn enamecolumn dnameaccept gname prompt like enter grade namebreak on department name duplicate skipset pause

Employee DepartmentName Name

3. Get the details of employee number, employee name, employee's department name, employee grade name using above sql reportingcommands

4. Get the departments which do not have employees.

5. Get the following report on emp table where paydate(first salary taken date) should be the last friday of the month if employee's hiredate is before 15th of that month otherwise first friday of next month.

empno ename hiredate paydate

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Exercise -4

INTRODUCTION TO SIMPLE VIEWS:

VIEW is a logical object. this will be created by using other tables with select statement. We use views to hide the table names

and query coplexity from user. We can rename the base table column in our view with column alias in the select query.

Example: create view dsk as select empno eno from emp;

UPDATABLE VIEWS:

This View should contain the mandatory columns of base tables, should not have aggregate functions,distinct

clause,group by or having clause.

Using drop view <viewname> we can destroy a view.Write queries for following .

1. Create a view to get a list of training programs attended by employee 'CMRCET' or another with ecode 2.

2. To create a view to get the current grade, current basic, increment step, maximum basic for ecode 3 and ename='CMRCET'.

3. Create views which should contain odd, even numbered rows of employee table.

4. Create a view with ename,dname,gname.

5. Delete duplicate rows from a table except last occurrence.

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Exercise -5Introduction to PL/SQL:

Pl/sql is a completely portable ,high performance transaction processing language .

DATA TYPES

BUILT-IN DATA TYPES

1. Number

Float Integer

2. character type char varchar2

3. Boolean4. Date

The basic pl/sql program structure is as following

Declare<All declarations> (%TYPE,%ROWTYPE)

Begin

<Executable statements>

Exception<Exception handling>

End;

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Control Structures:

1. If <condition> then<statements>

End if;

2. If <condition> then<statements>

elsif <condition> then<statements>

else <statements>

End if;

Loops:

1. GOTO:<<lablename>><statements>go to lablename;

2. Simple loop:loop

<statements>exit <condition>

end loop

3. For loop:for <counter> in <startvalue> .. <end value>loop

<statements>end loop

4. While loop:While <condition>loop

<statements>end loop;

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Write the following specified programs

1. To find whether the given number is palindrome or not ?

2. To find all Armstrong number below given number.

3. To count the words, vowels, consonants and length of the given string (Hint: substr).

4. To handle zero_divide,value_error and your exceptions.

5. To print prime numbers between 100 and 500.

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Exercise –6

Exceptions

In pl/sql ,a warning or error condition is called an exception. Exceptions can be internally defined (by the runtime system)Or user defined .Unlike internal exceptions, user defined exceptions must be given names.

When an error occurs , exception is raised. That is, normal execution stops and control transfers to the exception-handling part of that pl/sql block or subprogram. Internal exceptions are raised implicitly (automatically) by runtime system. User-defined exceptions must be raised explicitlyby RAISE statements, which can also predefined exceptions.

Few of the pre defined oracle errors are

1. dup_val_on_index:

Try to store duplicate values in a database column that is constrained by a unique index.

2. Invalid_number

3. Login_denined

4. No_data_found

5. Not_logged_on

6. Program_error

7. Zero_divide

Ect..

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USER_DEFINED EXCEPTION

A USER_DEFINED EXCEPTION should be declared and raised explicitly by a raise statement. It can be declared only in the declarative part of the pl/sql block. The syntax is as follows:

<exception_name> exception;

The syntax for ‘raise’ statement follows.

Raise<exception_name>; 1.write a pl/sql block to raise an exception if employee number read is not found when employee details are displayed.

2. Write a program to implement Not_logged_on exception.

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Exercise –7

CURSORS

Oracle uses work areas to execute SQL statements and store processing information. A PL/SQL construct called cursor lets us you name a work area and access its stored information. There are 2 types of cursors.

IMPLICIT CURSOR:Is the cursor which is always generated Implicitly by the oracle. We can use the Implicit cursor as SQL ,which is its name.

EXPLICIT CURSORSThese cursors are always defined by the user in PL/SQL block with the following syntax.

DECLARECURSOR <Cursorname> IS <Select statement>;

BEGIN< Select statements>;

END;

PARAMETRIC CURSORS:

Parameterized cursors is used to give parameters while opening the cursor. These parameters are to substitute in cursor declaration.

We use OPEN, FETCH, CLOSE statements to control a Cursor.

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CURSOR ATTRIBUTES:

%FOUND%NOTFOUND%ISOPEN%ROWCOUNT

Using the above attributes we can Know the different states of cursor.

CURSOR FOR LOOP:

FOR VARIABLE IN CURSORLOOP

<statements>END LOOP;

FOR UPDATE CLAUSE:Is used to restrict update on particular columns by selecting

those columns in for update clause.

CURRENT OF <cursorname>

Is used in where clause to update the current record of cursor but cursor should have for update clause.

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EXERCISE

1 Write a program to display employee table using cursor also handle cursor exceptions.

2 Write a program to display employee name and department name using one cursor.

3 Write a program to find experience of each employee using parameterized cursor.

4 Write a program to update the database using cursors based on the following conditions handling exceptions.

1. If Basic is greater than Rs.1500.00 then give increment of Rs.200.00.

2. If Basic is between Rs.1501.00 and Rs.3000.00 then give increment of Rs.500.00.

3. If Basic is greater than Rs.3000.00 then give increment of Rs.750.00.

5 Write a program to delete a particular row using cursor.

6 Write a program to print rows from last to first using cursor.

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Exercise-8

SUBPROGRAMS

A subprogram is used to reduce the program in size. we use the same set of statements to be executed for the different values, so we write the same set of statements as a subprogram.

A subprogram can be a function or procedure in PL/SQL which has to be created separately as a database object.

FUNCTION

Basically function is to return a value of various data types available. To get the function result we have to assign function to returntype variable. Function can't return more than one value.

Example:Create or replace function add(a number, b number)return number is

C number;BeginC:=a+b;Return C;End;

Exercise:

1. Write a function to get the factorial of given number.2. Write a function to check the existing of employee for given

employee number.

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Exercise-9

PROCEDURE

Basically a procedure is used to perform some task which may return one value or more than one value or no value. we use

parameters to get the result of procedures.

MODES OF PARAMETER:

IN Read only value Right side of :=

literal,expression,variable

OUT Write only value Left side of :=

Only Un initialized variable. IN OUT Read&Write Value Left & Right side of :=

Only Initialized variable

Example:

Create or replace procedure add(a in number, b in number, c out number) is

BeginC:=a+b;End;

Exercise:

1. Write a procedure to insert a row into your table.2. Write a procedure to insert a particular record in some other table

while deleting from a table.

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Exercise -10

PACKAGE:

Package is used to group the related functions and procedures of a database. A Package will be created as 2 different objects package specification and package body. The functions and procedures in that packages are treated as members of that package object but not as database objects. Before creating the package body there should be package specification for that package.

PACKAGE SPECIFICATION:create or replace package <packagename> asvariable that you want to include in this package;cursors that are common for the entire package;function prototype declaration of a function with return type;procedure prototype declaration of a procedure;end <packagename>

PACKAGE BODY:create or replace package body <packagename> as body of a function ;(by discarding create or replace as in ordinary function);

body of a procedure ;(by discarding create or replace as in ordinary procedure);

end <packagename>

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Exercise:

1. Write a package with functions isprime, isarmstrong, ispositive, isnegative to check whether the given number is prime, Armstrong, positive, negative respectively.

2. Include following procedures, variables in the above package.a) Procedure that displays a number in words for a given integer.b) Procedure that deletes the records in a table based on the parameter.variables:a)Pi valueb)e valuecusors:a)cursor that with all the columns of employee table.b)cursor that can have only department 10 employee details.

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Exercise-11

TRIGGER

A Trigger is PL/SQL block which can be executed without explicit calling at the time of DML operations on a table.

Types of Triggers:

Triggers are categorized base on when they are fired:

Before After For each row For each statement(default)

Syntax:create or replace trigger <triggername> {before/after/instead of}{insert/delete/update[of column1[,column2..]]} on <table name/view name > [for each statement/ row] [when <condition>]

DECLARE<declarations>BEGIN

<executable statements>END;

INSTEAD OF trigger is only for views.

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Note:1) A Database trigger can also have declarative and exception

Handling parts.2) A sub query cannot be included in when clause.

Enable/Disable:

Alter trigger <triggername> enable/disable;

Alter table <tablename> disable all;

EXERCISE

TABLES FOR NEXT EXERCISE

employee(empno, hiredate, dob, sal, appno).personal(empno, address, phno, email).selected(appno, dateofInterview).application(appno, ename, address, phno, enmail, qualification, dob,

designation).

1. create necessary triggers which insert employees personal details in personal table after inserting in employee table.

2. Create a trigger before insert/update/delete of employee details to stop the transactions on Saturdays and Sundays.

3. Create a trigger to check detail records while deleting or updating master records at master table.

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Exercise-12

FORMS

Developer 2000 Forms is used to develop Client/Server applications by which can be used to enter, access, change or delete data from oracle database in A form based environment.

Form

A Form module is nothing but collection of objects such as windows, Block , canvas, items, event based PL/SQL Code blocks called Form Triggers

MenuCollection of Objects such as menu items, submenus, submenu

items And PL/SQL Code blocks.

PL/SQL LibrariesCollection of PL/SQL functions and procedures stored in a single Library file. This library file is then attached to a form/menu.

ItemThese are objects contained in blocks, that present data values to the user depending upon the item type(text, checkbox, list ,radio group, button...).

BlockA block is group of related items. They can be span over many canvases.

Data block: Is associated with data(tables) with in the databaseControl block: Is not associated with any of the data in the database.

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Canvasview

A canvasview is a "surface" where visual objects are arranged.

Window window is similar to an empty picture frame, which can hold the

canavasview and allows to resize, move the canvaseview.

TriggerA forms object it associates a Pl/SQL block with an event.

REPORTS

Data model which is used to give the query and Data model-> editor -> SQL -> click in the editor: Q1 ->

propertiesSelect the necessary columns from tables to get the report.

Exercise

1. Develop a form to contain 3 different blocks on emp, dept, salgrade tables. Enforce the constraints on this

2. Develop a form to display the time and college name in a form using control block.

3. Develop a master detail blocks form for dept, emp tables along with navigation items.

4. Create simple report in tabuler model with the details of employee ename, department name, salary, next increment date ( assume that every year from the joining date each employee get increment).

5. Generate a master details report with the department name and total no.of employees and total salary of that department.

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dbms-lab-

Documents

type of data

invalid data

data storage

related data

table columnname data

data base object table

data type different

new data type