Gudlavalleru Engineering College Gudlavalleru

Department of Computer Science and Engineering DBMS Lab Manual for Students

II B.Tech II Sem R-10

1 Execute a single line and group functions for a table.

2 E x e c u t e D C L a n d T C L C o m m a n d s .

3 Create and manipulate various DB objects for a table.

4 Create views, partitions and locks for a particular DB

5 Write PL/SQL procedure for an application using exception handling

6 Write PL/SQL procedure for an application using cursors.

7 Write a DBMS program to prepare reports for an application using functions.

8 Write a PL/SQL block for transaction operations of a typical application using triggers.

9 Write a PL/SQL block for transaction operations of a typical application using package.

10

Design and develop an application using any front end and back end tool (make use of ER diagram and DFD).

11 Create table for various relation.

12 Implement the query in sql for a) insertion b) retrieval c) updating d) deletion.

13 C r ea t i n g V i e ws

14 Wr i t i n g As s e r t i o n

15 Wr i t i n g T r i g g er s

16 Implementing operation on relation using PL/SQL

17 C r ea t i n g F or ms

18 G en er a t i n g R ep or t s

Exp No : 1

1. Execute a single line and group functions for a table.

Single-Row Functions

Single-row functions can be nested to any level. Single-row functions can manipulate the following:

• Character data: LOWER, UPPER, INITCAP, CONCAT, SUBSTR, INSTR, LENGTH

• Number data: ROUND, TRUNC, MOD

• Date data: MONTHS_BETWEEN, ADD_MONTHS, NEXT_DAY, LAST_DAY, ROUND, TRUNC

• Date values can also use arithmetic operators.

• Conversion functions can convert character, date, and numeric values: TO_CHAR, TO_DATE,

TO_NUMBER

• There are several functions that pertain to nulls, including NVL, NVL2, NULLIF, and

COALESCE.

SELECT 'The job id for '||UPPER(last_name)||' is '

||LOWER(job_id) AS "EMPLOYEE DETAILS"

FROM employees;

SELECT employee_id, last_name, department_id

FROM employees

WHERE LOWER(last_name) = ‘higgins‘;

SELECT employee_id, UPPER(last_name), department_id

FROM employees

WHERE INITCAP(last_name) = ‘Higgins‘;

SELECT employee_id, CONCAT(first_name, last_name) NAME,

job_id, LENGTH (last_name),

INSTR(last_name, ‘a‘) "Contains ‘a‘?"

FROM employees

WHERE SUBSTR(job_id, 4) = ‘REP‘;

SELECT ROUND(45.923,2), ROUND(45.923,0),

ROUND(45.923,-1)

FROM DUAL;

SELECT TRUNC(45.923,2), TRUNC(45.923),

TRUNC(45.923,-2)

FROM DUAL;

SELECT last_name, (SYSDATE-hire_date)/7 AS WEEKS

FROM employees

WHERE department_id = 90;

SELECT employee_id, hire_date,

MONTHS_BETWEEN (SYSDATE, hire_date) TENURE,

ADD_MONTHS (hire_date, 6) REVIEW,

NEXT_DAY (hire_date, ‘FRIDAY‘), LAST_DAY(hire_date)

FROM employees

WHERE MONTHS_BETWEEN (SYSDATE, hire_date) < 36;

Types of Group Functions

• AVG

• COUNT

• MAX

• MIN

• STDDEV

• SUM

• VARIANCE

SELECT AVG(salary), MAX(salary),

MIN(salary), SUM(salary)

FROM employees

WHERE job_id LIKE ‘%REP%‘;

Ex:

Write a query to convert null values to zero using NVL function for displaying annual salary.

Write a query to display distinct values of DEPTNO and JOB.

List the details of the employees in departments 10 and 20 in alphabetical order of names.

Display sum of salaries group by job from emp table

Display deptno and average salary of all departments having more than 3 employees.

List all clerks who earn between 1000 and 2000.

Display Name,Job,Annual salary and commission of all sales people whose monthly salary is greater than

their commission. List the output order by salary.

List the minimum and maximum salary for each job type.

Convert the first letter of the ename into capital and remaining small letters

Display the first three characters of the ename where job is salesman.

Replace ‗a‘ present in the ename with ‗e‘.

Give the total number of people for each department.

Display the 60 days before from the hiredate for employee number 7788..

Display each employee name with hiredate and salary review date.

Display the system date in the format ―Wednesday 30 th July 2003‖.

Display ―30 th of July 2003‖ in the date format.

List the employee name ,job and salary increased by 15% for employees whose job is

Find the employees who earn lowest salary in each department

Display employees who earn more than the lowest salary in department 30.

Write a query to find employees who earn more than every employee in department 30.

Display name, job, and hiredate for employees whose salary is greater than the highest salary in any sales

department.

Find the employees who earn a salary greater than the average salary for each department .

Exp No : 2

2. Execute DCL and TCL Commands.

DCL Data Control Language (DCL) statements is used to create roles, permissions, and referential integrity as well it is used to control access to database by securing it. DCL Commands: Grant, Revoke GRANT - gives user's access privileges to database

REVOKE - withdraw access privileges given with the GRANT command

CREATE USER user

IDENTIFIED BY password;

GRANT privilege [, privilege...]

TO user [, user| role, PUBLIC...];

GRANT create session, create table,

create sequence, create view

TO scott;

Grant succeeded.

CREATE ROLE manager;

Role created.

GRANT create table, create view

TO manager;

Grant succeeded.

GRANT manager TO DEHAAN, KOCHHAR;

Grant succeeded.

GRANT object_priv[(columns)]

ON object

TO {user|role|PUBLIC}

[WITH GRANT OPTION];

REVOKE {privilege [, privilege...]|ALL}

ON object

FROM {user[, user...]|role|PUBLIC}

[CASCADE CONSTRAINTS];

REVOKE select, insert

ON departments

FROM scott;

Revoke succeeded.

TCL

Transaction Control (TCL) statements are used to manage the changes made by DML statements. It

allows statements to be grouped together into logical transactions.

TCL Commands: Commit, Rollback, Save point

COMMIT - save work done

SAVEPOINT - identify a point in a transaction to which you can later roll back

ROLLBACK - restore database to original since the last COMMIT

DELETE FROM test;

25,000 rows deleted.

ROLLBACK;

Rollback complete.

DELETE FROM test

WHERE id = 100;

1 row deleted.

SELECT *

FROM test

WHERE id = 100;

No rows selected.

COMMIT;

Commit complete.

SAVEPOINT

Save changes to a point (transactional).

Syntax: SAVEPOINT text_identifier

Example:

UPDATE employees

SET salary = 95000

WHERE last_name = 'Smith';

SAVEPOINT justsmith;

UPDATE employees

SET salary = 1000000;

SAVEPOINT everyone;

SELECT SUM(salary) FROM employees;

ROLLBACK TO SAVEPOINT justsmith;

COMMIT;

UPDATE...

SAVEPOINT update_done;

Savepoint created.

INSERT...

ROLLBACK TO update_done;

Rollback complete.

Exp No : 3

3. Create and manipulate various DB objects for a table.

Database Objects

An Oracle database can contain multiple data structures. Each structure should be outlined in the database

design so that it can be created during the build stage of database development.

• Table: Stores data

• View: Subset of data from one or more tables

• Sequence: Numeric value generator

• Index: Improves the performance of some queries

• Synonym: Gives alternative names to objects

CREATE TABLE [schema.]table

(columndatatype[DEFAULT expr][, ...]);

CREATE [OR REPLACE] [FORCE|NOFORCE] VIEW view

[(alias[, alias]...)]

AS subquery

[WITH CHECK OPTION [CONSTRAINT constraint]]

[WITH READ ONLY [CONSTRAINT constraint]];

CREATE SEQUENCE sequence

[INCREMENT BY n]

[START WITH n]

[{MAXVALUE n | NOMAXVALUE}]

[{MINVALUE n | NOMINVALUE}]

[{CYCLE | NOCYCLE}]

[{CACHE n | NOCACHE}];

CREATE INDEX index

ON table (column[, column]...);

CREATE [PUBLIC] SYNONYM synonym

FOR object;

Ex:

1. Create index vamsi on emp(eid);

2. Create index ramu on emp(eid,ename);

3. Create unique index srinu on emp(eid,ename,did);

.

Exp No : 4

4. Create views, partitions and locks for a particular DB

Partitioning:

enables you to decompose very large tables and indexes into smaller and more manageable pieces

called partitions. Each partition is an independent object with its own name and optionally its own storage

characteristics.

Partitioning is useful for many different types of database applications, particularly those that manage large

volumes of data. Benefits include:

Increased availability

The unavailability of a partition does not entail the unavailability of the object. The

query optimizer automatically removes unreferenced partitions from the query plan so queries are not

affected when the partitions are unavailable.

Easier administration of schema objects

A partitioned object has pieces that can be managed either collectively or individually. DDL statements can

manipulate partitions rather than entire tables or indexes. Thus, you can break up resource-intensive

tasks such as rebuilding an index or table. For example, you can move one table partition at a time. If a

problem occurs, then only the partition move must be redone, not the table move. Also, dropping a

partition avoids executing numerous DELETE statements.

Reduced contention for shared resources in OLTP systems

In some OLTP systems, partitions can decrease contention for a shared resource. For example, DML is

distributed over many segments rather than one segment.

Enhanced query performance in data warehouses

In a data warehouse, partitioning can speed processing of ad hoc queries. For example, a sales table

containing a million rows can be partitioned by quarter.

Partition Characteristics

Each partition of a table or index must have the same logical attributes, such as column names, data types, and

constraints. For example, all partitions in a table share the same column and constraint definitions, and all

partitions in an index share the same indexed columns. However, each partition can have separate physical

attributes, such as the tablespace to which it belongs.

Partition Key

The partition key is a set of one or more columns that determines the partition in which each row in a

partitioned table should go. Each row is unambiguously assigned to a single partition.

In the sales table, you could specify the timid column as the key of a range partition. The database assigns

rows to partitions based on whether the date in this column falls in a specified range. Oracle Database

automatically directs insert, update, and delete operations to the appropriate partition by using the partition

key.

Partitioning Strategies

Oracle Partitioning offers several partitioning strategies that control how the database places data into partitions.

The basic strategies are range, list, and hash partitioning.

A single-level partitioning strategy uses only one method of data distribution, for example, only list partitioning

or only range partitioning. In composite partitioning, a table is partitioned by one data distribution method

and then each partition is further divided into subpartitions using a second data distribution method. For

example, you could use a list partition for channel_id and a range subpartition for time_id.

Range Partitioning

In range partitioning, the database maps rows to partitions based on ranges of values of the partitioning key.

Range partitioning is the most common type of partitioning and is often used with dates.

Suppose that you want to populate a partitioned table with the sales rows shown in

Example Sample Row Set for Partitioned Table

PROD_ID CUST_ID TIME_ID CHANNEL_ID PROMO_ID QUANTITY_SOLD AMOUNT_SOLD

116 11393 05-JUN-99 2 999 1 12.18

40 100530 30-NOV-98 9 33 1 44.99

118 133 06-JUN-01 2 999 1 17.12

133 9450 01-DEC-00 2 999 1 31.28

36 4523 27-JAN-99 3 999 1 53.89

125 9417 04-FEB-98 3 999 1 16.86

30 170 23-FEB-01 2 999 1 8.8

24 11899 26-JUN-99 4 999 1 43.04

35 2606 17-FEB-00 3 999 1 54.94

45 9491 28-AUG-98 4 350 1 47.45

You create time_range_sales as a partitioned table using the statement in The time_id column is the partition

key.

Example 4-2 Range-Partitioned Table

CREATE TABLE time_range_sales

( prod_id NUMBER(6) , cust_id NUMBER, time_id DATE, channel_idCHAR(1), promo_idNUMBER(6)

, quantity_sold NUMBER(3) , amount_soldNUMBER(10,2) )

PARTITION BY RANGE (time_id)

(PARTITION SALES_1998 VALUES LESS THAN (TO_DATE('01-JAN-1999','DD-MON-YYYY')),

PARTITION SALES_1999 VALUES LESS THAN (TO_DATE('01-JAN-2000','DD-MON-YYYY')),

PARTITION SALES_2000 VALUES LESS THAN (TO_DATE('01-JAN-2001','DD-MON-YYYY')),

PARTITION SALES_2001 VALUES LESS THAN (MAXVALUE) );

Afterward, you load time_range_sales with the rows from shows the row distributions in the four partitions.

The database chooses the partition for each row based on the time_id value according to the rules specified

in the PARTITION BY RANGE clause.

Lock Table:

Use the LOCK TABLE statement to lock one or more tables, table partitions, or table sub partitions

in a specified mode. This lock manually overrides automatic locking and permits or denies

access to a table or view by other users for the duration of your operation.

Some forms of locks can be placed on the same table at the same time. Other locks allow only

one lock for a table.

A locked table remains locked until you either commit your transaction or roll it back, either

entirely or to a save point before you locked the table.

Locking Table:

AIM: To learn commands related to Table Locking

LOCK TABLE Statement Manually lock one or more tables.

Syntax: LOCK TABLE [schema.] table [options] IN lockmode MODE [NOWAIT]

LOCK TABLE [schema.] view [options] IN lockmode MODE [NOWAIT]

Options:

PARTITION (partition)

SUBPARTITION (subpartition)

@dblink

lockmodes:

EXCLUSIVE

SHARE

ROW EXCLUSIVE

SHARE ROW EXCLUSIVE

ROW SHARE* | SHARE UPDATE*

If NOWAIT is omitted Oracle will wait until the table is available.

Several tables can be locked with a single command - separate with commas

e.g. LOCK TABLE table1,table2,table3 IN ROW EXCLUSIVE MODE;

Default Locking Behaviour :

A pure SELECT will not lock any rows.

INSERT, UPDATE or DELETE's - will place a ROW EXCLUSIVE lock.

SELECT...FROM...FOR UPDATE NOWAIT - will place a ROW EXCLUSIVE lock.

Multiple Locks on the same rows with LOCK TABLE

Even when a row is locked you can always perform a SELECT (because SELECT doesnot

lock any rows) in addition to this, each type of lock will allow additional locks to be granted as

follows.

ROW SHARE = Allow ROW EXCLUSIVE or ROW SHARE or SHARE locks to be granted to the

locked rows.

ROW EXCLUSIVE = Allow ROW EXCLUSIVE or ROW SHARE locks to be granted to

the locked rows.

SHARE ROW EXCLUSIVE = Allow ROW SHARE locks to be granted to the locked rows.

SHARE = Allow ROW SHARE or SHARE locks to be granted to the locked rows.

EXCLUSIVE = Allow SELECT queries only

Ex:

1) Create view d10emp such that it contains only empno,ename,sal in department 10. 2) Update the view d10emp such that the sal is 8000 where the sal is 5000 observe the change in base table. 3) Create a view double from emp table and dept table containing the columns ename, job, deptno from emp table

and dname,loc from dept table.

Exp No : 5

5. Write PL/SQL procedure for an application using exception handling

DECLARE

huge_quantity EXCEPTION;

CURSOR product_quantity is

SELECT p.product_name as name, sum(o.total_units) as units

FROM order_tems o, product p

WHERE o.product_id = p.product_id;

quantityorder_tems.total_units%type;

up_limit CONSTANT order_tems.total_units%type := 20;

message VARCHAR2(50);

BEGIN

FOR product_rec in product_quantity LOOP

quantity := product_rec.units;

IF quantity >up_limit THEN

message := 'The number of units of product ' || product_rec.name ||

' is more than 20. Special discounts should be provided.

Rest of the records are skipped. '

RAISE huge_quantity;

ELSIF quantity <up_limit THEN

v_message:= 'The number of unit is below the discount limit.';

END IF;

dbms_output.put_line (message);

END LOOP;

EXCEPTION

WHEN huge_quantity THEN

dbms_output.put_line (message);

END;

QUERY: 1. Write a plsql program to handle built in exceptions 2. Write a PL/SQLprogram which includes declaration,executable

and exception handling section 3. Write a PL/SQL program to design user design exceptions 4. Write a PL/SQL block use raise_application_error

Exp No : 6

6. Write PL/SQL procedure for an application using cursors.

DECLARE

CURSOR csr_ac (p_name VARCHAR2) IS

SELECT empno, name, sal

FROM employee

WHERE name LIKE '%p_name%';

v_aemployee.empno%TYPE;

v_bemployee.name%TYPE;

v_cemployee.sal%TYPE;

BEGIN

OPEN csr_ac ('LE');

LOOP

FETCH csr_ac INTO a, b, c;

EXIT WHEN csr_ac%NOTFOUND;

DBMS_OUTPUT.PUT_LINE(v_a || ' ' || v_b || ' '||v_c);

END LOOP;

CLOSE csr_ac;

END;

Exp No : 7

7. Write a DBMS program to prepare reports for an application using functions.

CREATE OR REPLACE FUNCTION get_sal

(p_id IN employees.employee_id%TYPE)

RETURN NUMBER

IS

v_salaryemployees.salary%TYPE :=0;

BEGIN

SELECT salary

INTO v_salary

FROM employees

WHERE employee_id = p_id;

RETURN v_salary;

END get_sal;

/

Ex: 1. PL/SQL program development using creation of stored functions.

Exp No : 8

8. Write a PL/SQL block for transaction operations of a typical application using

triggers.

Guidelines for Designing Triggers

• Use triggers to guarantee that when a specific operation is performed, related actions

• Use database triggers only for centralized, global operations that should be fired for the

triggeringstatement, regardless of which user or application issues the statement.

• Do not define triggers to duplicate or replace the functionality already built into the

Oracledatabase. For example do not define triggers to implement integrity rules that can be done

by usingdeclarative constraints. An easy way to remember the design order for a business rule is

to:

– Use built-in constraints in the Oracle server such as, primary key, foreign key and so on

– Develop a database trigger or develop an application such as a servlet or Enterprise

JavaBean (EJB) on your middle tier

– Use a presentation interface such as Oracle Forms, dynamic HTML, JavaServerPages

(JSP) and so on, if you cannot develop your business rule as mentioned above, which mightbe a

presentation rule.

• The excessive use of triggers can result in complex interdependencies, which may be difficult

tomaintain in large applications. Only use triggers when necessary, and beware of recursive

andcascading effects.

Trigger timing: When should the trigger fire?

• BEFORE: Execute the trigger body before the

triggering DML event on a table.

• AFTER: Execute the trigger body after the

triggering DML event on a table.

• INSTEAD OF: Execute the trigger body instead of

the triggering statement. This is used for views

that are not otherwise modifiable.

CREATE [OR REPLACE] TRIGGER trigger_name

timing

event1 [OR event2 OR event3]

ON table_name

trigger_body

CREATE OR REPLACE TRIGGER secure_emp

BEFORE INSERT ON employees

BEGIN

IF (TO_CHAR(SYSDATE,'DY') IN ('SAT','SUN')) OR

(TO_CHAR(SYSDATE,'HH24:MI')

NOT BETWEEN '08:00' AND '18:00')

THEN RAISE_APPLICATION_ERROR (-20500,'You may

insert into EMPLOYEES table only

during business hours.');

END IF;

END;

/

Trigger Created..

INSERT INTO employees (employee_id, last_name,

first_name, email, hire_date,

job_id, salary, department_id)

VALUES (300, 'Smith', 'Rob', 'RSMITH', SYSDATE,

'IT_PROG', 4500, 60);

Ex:

1. Write a trigger for before delete on employee table. 2. Create a trigger for After insert on employee table. 3. Write a trigger in pl/sql that stores update,delete,insert operations on emp2 table;

Exp No : 9

9. Write a PL/SQL block for transaction operations of a typical application using

package.

A package is a schema object that groups logically related PL/SQL types, items, and

subprograms. Packages usually have two parts, a specification and a body, although

sometimes the body is unnecessary. Thespecification (spec for short) is the interface to your

applications; it declares the types, variables, constants, exceptions, cursors, and subprograms

available for use. The body fully defines cursors and subprograms, and so implements the

spec.

CREATE [OR REPLACE] PACKAGE package_name

[AUTHID {CURRENT_USER | DEFINER}]

{IS | AS}

[PRAGMA SERIALLY_REUSABLE;]

[collection_type_definition ...]

[record_type_definition ...]

[subtype_definition ...]

[collection_declaration ...]

[constant_declaration ...]

[exception_declaration ...]

[object_declaration ...]

[record_declaration ...]

[variable_declaration ...]

[cursor_spec ...]

[function_spec ...]

[procedure_spec ...]

[call_spec ...]

[PRAGMA RESTRICT_REFERENCES(assertions) ...]

END [package_name];

CREATE OR REPLACE PACKAGE emp_actionsAS -- spec

TYPE EmpRecTyp IS RECORD (emp_id INT, salary REAL);

CURSOR desc_salary RETURN EmpRecTyp;

PROCEDURE hire_employee (

ename VARCHAR2,

job VARCHAR2,

mgr NUMBER,

sal NUMBER,

comm NUMBER,

deptno NUMBER);

PROCEDURE fire_employee (emp_id NUMBER);

END emp_actions;

CREATE OR REPLACE PACKAGE BODY emp_actionsAS -- body

CURSOR desc_salary RETURN EmpRecTyp IS

SELECT empno, sal FROM emp ORDER BY sal DESC;

PROCEDURE hire_employee (

ename VARCHAR2,

job VARCHAR2,

mgr NUMBER,

sal NUMBER,

comm NUMBER,

deptno NUMBER) IS

BEGIN

INSERT INTO emp VALUES (empno_seq.NEXTVAL, ename, job,

mgr, SYSDATE, sal, comm, deptno);

END hire_employee;

PROCEDURE fire_employee (emp_id NUMBER) IS

BEGIN

DELETE FROM emp WHERE empno = emp_id;

END fire_employee;

END emp_actions;

Exp No : 10

10. Design and develop an application using any front end and back end tool (make use

of ER diagram and DFD).

Step 1:

Let us take a very simple example and we try to reach a fully organized database from it. Let us look at

thefollowing simple statement:

A boy eats an ice cream.

This is a description of a real word activity, and we may consider the above statement as a written document

(very short, of course).

Step 2:

Now we have to prepare the ERD. Before doing that we have to process the statement a little. We can see

that the sentence contains a subject (boy), an object (ice cream) and a verb (eats) that defines the

relationship between the subject and the object. Consider the nouns as entities (boy and icecream) and the

verb (eats) as a relationship. To plot them in the diagram, put the nouns within rectangles and the

relationship within a diamond. Also, show the relationship with a directed arrow, starting from the subject

entity (boy) towards the object entity (ice cream).

Well, fine. Up to this point the ERD shows how boy and ice cream are related. Now, every boy must have a

name, address, phone number etc. and every ice cream has a manufacturer, flavor, price etc. Without these

the diagram is not complete. These items which we mentioned here are known as attributes, and they must

be incorporated in the ERD as connected ovals.

But can only entities have attributes? Certainly not. If we want then the relationship must have their

attributes too. These attribute do not inform anything more either about the boy or the ice cream, but they

provide additional information about the relationships between the boy and the ice cream.

Step:3

We are almost complete now. If you look carefully, we now have defined structures for at least three tables

like the following:

Boy

Name Address Phone

Ice Cream

Manufacturer Flavor Price

Eats

Date Time

However, this is still not a working database, because by definition, database should be ―collection of

related tables.‖ To make them connected, the tables must have some common attributes. If we chose the

attribute Name of the Boy table to play the role of the common attribute, then the revised structure of the

above tables become something like the following.

Boy

Name Address Phone

Ice Cream

Manufacturer Flavor Price Name

Eats

Date Time Name

This is as complete as it can be. We now have information about the boy, about the ice cream he has eaten

and about the date and time when the eating was done.

Cardinality of Relationship

While creating relationship between two entities, we may often need to face the cardinality problem. This simply means that how many entities of the first set are related to how many entities of the second set. Cardinality can be of the following three types.

One-to-One

Only one entity of the first set is related to only one entity of the second set. E.g. A teacher teaches a

student. Only one teacher is teaching only one student. This can be expressed in the following diagram as:

One-to-Many Only one entity of the first set is related to multiple entities of the second set. E.g. A teacher teaches

students. Only one teacher is teaching many students. This can be expressed in the following diagram as:

Many-to-One Multiple entities of the first set are related to multiple entities of the second set. E.g. Teachers teach a

student. Many teachers are teaching only one student. This can be expressed in the following diagram as:

Many-to-Many Multiple entities of the first set is related to multiple entities of the second set. E.g. Teachers teach students.

In any school or college many teachers are teaching many students. This can be considered as a two way

one-to-many relationship. This can be expressed in the following diagram as:

In this discussion we have not included the attributes, but you can understand that they can be used without

any problem if we want to.

The Concept of Keys

A key is an attribute of a table which helps to identify a row. There can be many different types of keys which

are explained here.

Super Key or Candidate Key: It is such an attribute of a table that can uniquely identify a row in a table.

Generally they contain unique values and can never contain NULL values. There can be more than one

super key or candidate key in a table e.g. within a STUDENT table Roll and Mobile No. can both serve to

uniquely identify a student.

Primary Key: It is one of the candidate keys that are chosen to be the identifying key for the entire table. E.g.

although there are two candidate keys in the STUDENT table, the college would obviously use Roll as the

primary key of the table.

Alternate Key: This is the candidate key which is not chosen as the primary key of the table. They are named

so because although not the primary key, they can still identify a row.

Composite Key: Sometimes one key is not enough to uniquely identify a row. E.g. in a single class Roll is

enough to find a student, but in the entire school, merely searching by the Roll is not enough, because there

could be 10 classes in the school and each one of them may contain a certain roll no 5. To uniquely identify

the student we have to say something like ―class VII, roll no 5‖. So, a combination of two or more attributes

is combined to create a unique combination of values, such as Class + Roll.

Foreign Key: Sometimes we may have to work with an attribute that does not have a primary key of its own.

To identify its rows, we have to use the primary attribute of a related table. Such a copy of another related

table‘s primary key is called foreign key.

Strong and Weak Entity

Based on the concept of foreign key, there may arise a situation when we have to relate an entity having a

primary key of its own and an entity not having a primary key of its own. In such a case, the entity having

its own primary key is called a strong entity and the entity not having its own primary key is called a weak

entity. Whenever we need to relate a strong and a weak entity together, the ERD would change just a little.

Say, for example, we have a statement ―A Student lives in a Home.‖ STUDENT is obviously a strong entity

having a primary key Roll. But HOME may not have a unique primary key, as its only attribute Address

may be shared by many homes (what if it is a housing estate?). HOME is a weak entity in this case.

The ERD of this statement would be like the following

As you can see, the weak entity itself and the relationship linking a strong and weak entity must have double

border.

Different Types of Database

There are three different types of data base. The difference lies in the organization of the database and the

storage structure of the data. We shall briefly mention them here.

RelationalDBMS This is our subject of study. A DBMS is relational if the data is organized into relations, that is, tables. In

RDBMS, all data are stored in the well-known row-column format.

HierarchicalDBMS In HDBMS, data is organized in a tree like manner. There is a parent-child relationship among data items

and the data model is very suitable for representing one-to-many relationship. To access the data items,

some kind of tree-traversal techniques are used, such as preorder traversal.

Because HDBMS is built on the one-to-many model, we have to face a little bit of difficulty to organize a

hierarchical database into row column format. For example, consider the following hierarchical database

that shows four employees (E01, E02, E03, and E04) belonging to the same department D1.

There are two ways to represent the above one-to-many information into a relation that is built in one-to-one

relationship. The first is called Replication, where the department id is replicated a number of times in the

table like the following.

Dept-Id Employee Code

D1 E01

D1 E02

D1 E03

D1 E04

Replication makes the same data item redundant and is an inefficient way to store data. A better way is to

use a technique called the Virtual Record. While using this, the repeating data item is not used in the table.

It is kept at a separate place. The table, instead of containing the repeating information, contains a pointer to

that place where the data item is stored.

This organization saves a lot of space as data is not made redundant.

Network DBMS The NDBMS is built primarily on a one–to-many relationship, but where a parent-child representation

among the data items cannot be ensured. This may happen in any real world situation where any entity can

be linked to any entity. The NDBMS was proposed by a group of theorists known as the Database Task

Group (DBTG). What they said looks like this:

In NDBMS, all entities are called Records and all relationships are called Sets. The record from where the

relationship starts is called the Owner Record and where it ends is called Member Record. The

relationship or set is strictly one-to-many.

In case we need to represent a many-to-many relationship, an interesting thing happens. In NDBMS, Owner

and Member can only have one-to-many relationship. We have to introduce a third common record with

which both the Owner and Member can have one-to-many relationship. Using this common record, the

Owner and Member can be linked by a many-to-many relationship.

Suppose we have to represent the statement Teachers teach students. We have to introduce a third record,

suppose CLASS to which both teacher and the student can have a many-to-many relationship. Using the

class in the middle, teacher and student can be linked to a virtual many-to-many relationship.

If i have my two tables like this:

CREATE TABLE accounts(

account_id INT NOT NULL AUTO_INCREMENT,

customer_id INT( 4 ) NOT NULL ,

account_type ENUM( 'savings', 'credit' ) NOT NULL,

balance FLOAT( 9 ) NOT NULL,

PRIMARY KEY ( account_id )

)

and

CREATE TABLE customers(

customer_id INT NOT NULL AUTO_INCREMENT,

name VARCHAR(20) NOT NULL,

address VARCHAR(20) NOT NULL,

city VARCHAR(20) NOT NULL,

state VARCHAR(20) NOT NULL,

)

Now, how do i create a 'relationship' between the two tables. I want each account to be 'assigned' one

customer_id

Exp No : 11

11. Create table for various relation.

To create a foreign key relationship in Table Designer

1. In Object Explorer, right-click the table that will be on the foreign-key side of the relationship and click

Design.

The table opens in Table Designer.

2. From the Table Designer menu, click Relationships.

3. In the Foreign-key Relationships dialog box, click Add.

The relationship appears in the Selected Relationship list with a system-provided name in the format

FK_<tablename>_<tablename>, where tablename is the name of the foreign key table.

4. Click the relationship in the Selected Relationship list.

5. Click Tables and Columns Specification in the grid to the right and click the ellipses (…) to the right of

the property.

6. In the Tables and Columns dialog box, in the Primary Key drop-down list, choose the table that will be

on the primary-key side of the relationship.

7. In the grid beneath, choose the columns contributing to the table's primary key. In the adjacent grid cell

to the left of each column, choose the corresponding foreign-key column of the foreign-key table.

Table Designer suggests a name for the relationship. To change this name, edit the contents of the

Relationship Name text box.

8. Choose OK to create the relationship.

To create a foreign key in a new table

1. In Object Explorer, connect to an instance of Database Engine.

2. On the Standard bar, click New Query.

3. Copy and paste the following example into the query window and click Execute. The example creates a

table and defines a foreign key constraint on the column TempID that references the column

SalesReasonID in the Sales.SalesReason table. The ON DELETE CASCADE and ON UPDATE

CASCADE clauses are used to ensure that changes made to Sales.SalesReason table are automatically

propagated to the Sales.TempSalesReason table.

USE AdventureWorks2012;

GO

CREATE TABLE Sales.TempSalesReason (TempIDint NOT NULL, Name nvarchar(50),

CONSTRAINT PK_TempSales PRIMARY KEY NONCLUSTERED (TempID),

CONSTRAINT FK_TempSales_SalesReason FOREIGN KEY (TempID)

REFERENCES Sales.SalesReason (SalesReasonID)

ON DELETE CASCADE

ON UPDATE CASCADE);

GO

To create a foreign key in an existing table

1. In Object Explorer, connect to an instance of Database Engine.

2. On the Standard bar, click New Query.

3. Copy and paste the following example into the query window and click Execute. The example creates a

foreign key on the column TempID and references the column SalesReasonID in the Sales.SalesReason

table.

USE AdventureWorks2012;

GO

ALTER TABLE Sales.TempSalesReason

ADD CONSTRAINT FK_TempSales_SalesReason FOREIGN KEY (TempID)

REFERENCES Sales.SalesReason (SalesReasonID)

ON DELETE CASCADE

ON UPDATE CASCADE;

GO

I suggest to use always a separated file with SQL statements to create all database's tables and relationships

between them. The code is very simple, easy to modify and to reuse. A relation is defined using the statement

REFERENCES:

CREATE TABLE CITY (

id_city_pk INT NOT NULL AUTO_INCREMENT,

city VARCHAR(100),

PRIMARY KEY (id_city_pk)) TYPE=INNODB;

CREATE TABLE USER (

id_user_pk INT NOT NULL AUTO_INCREMENT,

nick VARCHAR(40),

email VARCHAR(40),

password VARCHAR(20),

id_city INT NOT NULL,

PRIMARY KEY (id_user_pk)

FOREIGN KEY (id_city) REFERENCES CITY(id_city_pk) ON UPDATE CASCADE ON DELETE

CASCADE) TYPE=INNODB;

Exp No : 12

12. Implement the query in sql for a) insertion b) retrieval c) updation d) deletion.

INSERT INSERT INTO table_name VALUES (value1, value2, value3,...); ( O R )

INSERT INTO table_name (column1, column2, column3,...) VALUES (value1, value2, value3,...); UPDATE UPDATE table_name SET column1=value, column2=value2,... WHERE some_column=some_value; DELETE DELETE FROM table_name WHERE some_column=some_value; SELECT SELECT column_name(s) FROM table_name;

Exp No : 13

13. Creating Views

CREATING AND DROPING OF VIEWS SQL> select * from emp2;

OUTPUT:-

ENAME STREET CITY -------------------- -------------------- --------------------

coyotetoonhollywood rabbit tunnel carrot ville smith revolver death valley williams sea view sea attle SQL> create view emp22 as select * from emp2; OUTPUT:- View created. SQL> select * from emp22; OUTPUT:- ENAME STREET CITY -------------------- -------------------- -------------------- coyotetoonhollywood rabbit tunnel carrot ville smith revolver death valley williams sea view sea attle

Exp No : 14

14. Writing Assertion

Specifying General Constraints as Assertions

SQL>

users can specify general constraints—those that do not fall into any of the categories

described

declarative assertions,

using the

CREATE

ASSERTION

statement of the

DDL

. Each assertion is given a constraint name and is specified via a condition

similar to the

WHERE

clause of an

SQL

query. For example, to specify the constraint that

―the salary of an employee must not be greater than the salary of the manager of the department

that the employee works for‖ in

SQL>

we can write the following assertion:

CREATE ASSERTION SALARY_CONSTRAINT

CHECK ( NOT EXISTS

(SELECT *

FROM EMPLOYEE E, EMPLOYEE M, DEPARTMENT D

WHERE E.SALARY>M.SALARY AND

E.DNO=D.DNUMBER AND

D.MGRSSN=M.SSN) );

Exp No : 15

15. Writing Triggers

To write a TRIGGER to ensure that DEPT TABLE does not contain duplicate of

null values in DEPTNO column.

INPUT

CREATE OR RELPLACE TRIGGER trig1 before insert on dept for each row

DECLARE

a number;

BEGIN

if(:new.deptno is Null) then

raise_application_error(-20001,'error::deptno cannot be null');

else

select count(*) into a from dept where deptno=:new.deptno;

if(a=1) then

raise_application_error(-20002,'error:: cannot have duplicate deptno');

end if;

end if;

END;

RESULT:

SQL> @trigger

Trigger created.

SQL> select * from dept;

DEPTNO DNAME LOC

--------- -------------- -------------

10 ACCOUNTING NEW YORK

20 RESEARCH DALLAS

30 SALES CHICAGO

40 OPERATIONS BOSTON

SQL> insert into deptvalues(&deptnp,'&dname','&loc');

Enter value for deptnp: null

Enter value for dname: marketing

Enter value for loc: hyd

old 1: insert into dept values(&deptnp,'&dname','&loc')

new 1: insert into dept values(null,'marketing','hyd')

insert into dept values(null,'marketing','hyd')

*

ERROR at line 1:

ORA-20001: error::deptno cannot be null

ORA-06512: at "SCOTT.TRIG1", line 5

ORA-04088: error during execution of trigger 'SCOTT.TRIG1'

SQL> /

Enter value for deptnp: 10

Enter value for dname: manager

Enter value for loc: hyd

old 1: insert into dept values(&deptnp,'&dname','&loc')

new 1: insert into dept values(10,'manager','hyd')

insert into dept values(10,'manager','hyd')

*

ERROR at line 1:

ORA-20002: error:: cannot have duplicate deptno

ORA-06512: at "SCOTT.TRIG1", line 9

ORA-04088: error during execution of trigger 'SCOTT.TRIG1'

SQL> /

Enter value for deptnp: 50

Enter value for dname: MARKETING

Enter value for loc: HYDERABAD

old 1: insert into dept values(&deptnp,'&dname','&loc')

new 1: insert into dept values(50,'MARKETING','HYDERABAD')

1 row created.

SQL> select * from dept;

DEPTNO DNAME LOC

--------- -------------- -------------

10 ACCOUNTING NEW YORK

20 RESEARCH DALLAS

30 SALES CHICAGO

40 OPERATIONS BOSTON

50 MARKETING HYDE

Exp No : 16.

16. Implementing operation on relation using PL/SQL

Writing PL/SQL block for insertion into atable: To write a PL/SQL block for inserting rows into EMPDET table with the following

Calculations:

HRA=50% OF BASIC

DA=20% OF BASIC

PF=7% OF BASIC

NETPAY=BASIC+DA+HRA-PF

INPUT

DECLARE

ENO1 empdet.eno%type;

ENAME1 empdet.name%type;

DEPTNO1 empdet.deptno%type;

BASIC1 empdet.basic%type;

HRA1 empdet.HRA%type;

DA1 empdet.DA%type;

PF1 empdet.pf%type;

NETPAY1 empdet.netpay%type;

BEGIN

ENO1:=&ENO1;

ENAME1:='&ENAME1';

DEPTNO1:=&DEPTNO1;

BASIC1:=&BASIC1;

HRA1:=(BASIC1*50)/100;

DA1:=(BASIC1*20)/100;

PF1:=(BASIC1*7)/100;

NETPAY1:=BASIC1+HRA1+DA1-PF1;

INSERT INTO EMPDET VALUES (ENO1, ENAME1, DEPTNO1, BASIC1,

HRA1, DA1, PF1, NETPAY1);

END;

RESULT:

SQL> @BASIC

Enter value for eno1: 104

old 11: ENO1:=&ENO1;

new 11: ENO1:=104;

Enter value for ename1: SRINIVAS REDDY

old 12: ENAME1:='&ENAME1';

new 12: ENAME1:='SRINIVAS REDDY';

Enter value for deptno1: 10

old 13: DEPTNO1:=&DEPTNO1;

new 13: DEPTNO1:=10;

Enter value for basic1: 6000

old 14: BASIC1:=&BASIC1;

new 14: BASIC1:=6000;

PL/SQL procedure successfully completed.

Ex:

1. Writing PL/SQL block for checking armstrong number

2. Writing a PL/SQL block for checking a number even or odd.

Exp No : 17.

17. Creating Forms

.

Use Form Builder to simplify for the creation of data-entry screens, also known as Forms.

Forms are the applications that connect to a database, retrieve information requested by the

user, present it in a layout specified by Form designer, and allow the user to modify or add

information. Form Builder allows you to build forms quickly and easily.

In this Hands-On, you learn how to: Create a Data block for the _Customer_ table, Create a

layout, Use _content_ canvas, Use _execute query_, Navigate a table, Use next, previous

record, Enter query, Manipulate table_s record, Insert, Update, Delete and Save record.

Form Builder Tool

Open the "Form Builder" tool.

Welcome window

You will get the _Welcome to the Form Builder_ window. If you don_t want to get this

window anymore uncheck the _Display at startup_ box. You can start your work with any of

the following options:

Use the data Block Wizard

Build a new form manually

Open an existing form

Build a form based on a template

The default is _Use the data Block Wizard._ If you want to build a new form manually, click on

"Cancel_ or check _Build a new form manually_ and click _OK._

Connect to database

In the _Object Navigator_ window, highlight "Database Objects." Go to the Main menu and

choose "File," then "Connect."

In the _Connect_ window, login in as _scott_ password _tiger,_ then click _CONNECT._

Notice that the box next to _Database Objects_ is not empty anymore and it has a _+_ sign in

it. That will indicate that this item is expandable and you are able to see its entire objects.

Click on the _+_ sign next to the _Database Objects_ to expand all database schemas.

Create a Module

In the _Object Navigator_ window, highlight module1. This is a default name. Go to the Main menu

and choose _File,_ select _Save as_ to store the new object in the _iself_ folder and save it as

customer data entry. "c:_de." In this example the _DE_ abbreviation stands for Data

Entry.

Create a Data Block

In the _Object Navigator_ window, highlight "Data Blocks,_ and click on the "create_ icon.

The _Create_ icon is in the vertical tool bar in the _Object Navigator_ window. It is a green

_+_ sign. If you drag your cursor on the icon a tooltip will show _Create._

New Data Block

In the _New Data Block_ window, choose the default option _Data Block Wizard_ and click

"OK."

Welcome Data Block

In the _Welcome Data Block Wizard_ window click on the _NEXT_ icon.

Type of Data Block

Select the type of data block you would like to create by clicking on a radio button. Select the

default option _Table or View_ and then click _NEXT_ again.

Selecting Tables

Click on _browse._ In the _Tables_ window, highlight the "cust11_ table; then click "OK."

Selecting columns for the Data Block Wizard

To choose all columns, click on the two arrow signs in the _Data Block Wizard_ window. To

choose selected columns, click on the one arrow sign. And then select all columns, and click

_next._

Layout Wizard

End of the Data Block Wizard and beginning of the Layout Wizard

In the _Congratulations_ screen, use the default checkmark radio button (Create the data

block, then call the Layout Wizard), and click "Finish." You can also use the Data Block

Wizard to modify your existing data block. Simply select the data block in the Object

Navigator and click the Data Block Wizard toolbar button, or choose _Data Block wizard_

from the _Tools_ menu.

Welcome screen

In the _Welcome to the Layout Wizard_ window, click _Next._

Selecting canvas

In the _Layout Wizard_ window, select the "new canvas" option. Canvas is a place that you

will have your objects such as columns, titles, pictures, etc. If you have already had your

canvas, select the canvas and then click on the next. The following are different types of

canvases: Content, Stacked, Vertical Toolbar, Horizontal Toolbar, and Tab.

Think of the _Content_ canvas as one flat place to have all your objects. In the stacked

canvas, you can have multiple layers of objects and it is the same as the tab canvas. You use

the vertical or horizontal toolbar canvases for your push buttons. Check the different types of

canvases by clicking on the _down arrow_ box next to the _Type_ field. Select "content," then

click _Next._

Selecting Columns for the Layout Wizard

In the _Layout Wizard_ window, select all the columns. These are the columns that you want

to be displayed on the canvas. Then click _Next._

Change your objects appearances

Change size or prompt if needed. In this window, you can enter a prompt, width, and height

for each item on the canvas. You can change the measurement units. As a default the default

units for item width and height are points. You can change it to inch or centimeter. When you

change size, click _Next._

Selecting a layout style

Select a layout style for your frame by clicking a radio button. Select "Form," if you want

one record at a time to be displayed. Select _Tabular,_ if you want more than one record at a

time to be displayed. Select "Forms," and then click _next._

Record layout

Type the "Frame Title" and click "next." Checkmark the _Display Scrollbar_ box when you

use multiple records or the _Tabular_ option.

Congratulation Screen

In the _Congratulations_ window, click "Finish."

You will see the output layout screen.

Make some window adjustments and then run the form. To run the form, click on the _Run_

icon. The _Run_ icon is on the horizontal toolbar in the _CUSTOMER_DE_ canvas.

The object module should be compiled successfully before executing the Form.

Execute Query

Click on the "Execute Query" icon below the main menu. If you drag the cursor on the

toolbar in the _Forms Runtime_ window, a tooltip will be displayed and you see _Execute

Query._

So to know all your option, drag your cursor to view all the icon descriptions.

Next Record

Click on the "Next Record" icon to navigate to the next record.

Previous Record

Click on the "Previous Record" icon to navigate to the previous record.

This is an easy way to navigate through the _Customer_ table.

Enter Query

Click on the "Enter Query" icon to query selected records.

Insert Record

Click "Insert Record" to add new customer. All items on the forms will be blanked. You can

either type all the customer information or duplicate it from pervious record.

Duplicate Record

To duplicate the previous record, go to the main menu and select the _Record_ sub-menu. A

drop down menu will be displayed. Select the _Duplicate_ option in the sub-menu.

Apply the changes. Remember in this stage, your record was inserted but not committed yet.

Next and Previous Record

Click "next record" and "previous record" to navigate through the records and the one was

added.

Save transactions

Click "Save" to commit the insert statement.

Delete Record

Click "Remove Record" to delete the record.

Lock a Record

You can also lock the record.

Exit from Form Runtime

Exit the FORM Runtime. If you have not committed any transaction, you will be prompted to

save changes. Click _YES_ to save changes.

Click _OK_ for acknowledgement.

Don_t forget to save the Form.

RABAD

Exp No : 18.

18. Generating Reports

AIM: To design reports using Oracle Developer 2000

Introduction

Tabular report shows data in a table format. It is similar in concept to the idea of an Oracle

table. Oracle, by default, returns output from your select statement in tabular format.

Hands-on

In this Hands-On, your client is a stock broker that keeps track of its customer stock

transactions. You have been assigned to write the reports based on their reports layout

requirements.

Your client wants you to create a simple listing report to show list of the stock trades by

using stocks table for their brokerage company

Your tasks are:

1- Write a tabular report.

2- Apply user layout Format mask.

3- Run the report.

4- Test the repot.

You will learn how to: use report wizard, object navigator, report builder, _date model_,

property palette, work on query and group box, see report style, use tabular style, navigating

throughreport_s record, change the format mask for dollar, numeric and date items.

Open Report Builder tool

Open the "Report Builder" tool.

Connect to database

In the Object Navigator, highlight "Database Objects,_ choose "File," then select the

"Connect" option.

In the _Connect_ window, login as _iself_ password schooling, then click _CONNECT._

Save a report

In the Object Navigator, highlight the "untitled" report, choose _File,_ and select the _Save

as_ option.

In the _Save as_ window, make sure to save the report in the ISELF folder and name it

"rpt01_stock_history,_ report number 1 stock history.

Data Model

In the Object Navigator, double click on the "Data Model" icon.

Create SQL box

In the Data Model window, click on the "SQL Query" icon. Then drag the plus sign cursor

and click it anywhere in the _Data Model_ screen where you wish your object to be.

In the _SQL Query Statement_ window, write a query to read all the stocks record sorted by

their symbol.

(SQL Query Statement)

SELECT * FROM stocks

ORDER BY symbol

Click _OK._

Change SQL box_s name

In the Data Model window, in the _SQL_ box, right click on the _Q_1_ and open its property

palette.

In its property palette, change the name to Q_STOCKS. Then close the window.

Change GROUP box_s name

In the Data Model, right click on the group box (G_SYMBOL) and open its property palette.

In the Group property palette, change the name to _G_STOCKS,_ and close the window.

Open Report Wizard

In the Data Model, click on the _Report Wizard_ icon on the horizontal tool bar.

In the Style tab, on the Report Wizard window, type _Stock History_ in the Title box and

choose the report style as _Tabular._

Notice that when you change the report style a layout of that report will be displayed on the

screen.

Choose a different style to display its layout of its report style.

Data, Fields, Totals, Labels and Template tabs

Click _NEXT_ to go to the Data tab. In the _SQL Query Statement_ verify your query.

Click _NEXT_ to navigate to the Fields tab, select the fields that you would like to be display

in your report. Select all the columns to be display.

Click _NEXT_ to navigate to Totals tab, select the fields for which you would like to

calculate totals. We have none in this hands-on exercise.

Click _NEXT_ to open the Labels tab, modify the labels and widths for your fields and totals

as desired.

Click _NEXT_ again to go to the Template tab, and choose a template for your report. Your

report will inherit the template_s colors, fonts, line widths, and structure.

Use the default template and click _finish._

Running a report

Now, you should have your output report on the screen.

Resize an object

Maximize the output report and format the report layout. To resize an object , select it and

drag its handler to the preferred size.

Move an object

To move an object, select and drag it while the cursor is on the object.

This is a simple report.

Navigate through

the output

To navigate

through the

output report in

the Report

Editor - Live

Pre-viewer,

click on the

"next page" or

"previous

page" icon on

the horizontal

toolbar.

Do the same with the "first page" or "last page" icon.

Use the _zoom in_ and _zoom out_ icon to preview the report.

Know report_s functions

Change the date "Format Mask" property and make it _year 2000 complaint (MM-DD-RR)._

To know each icon functionalities, drag your cursor on it and a tooltip will display its

function.

Change Format Mask

To change the "format mask" of a column, the column should be selected. Then go to the

toolbar and click on the _$_ icon, "add decimal place," and the _right justify_ format to the all

currency columns (Todays Low, Todays High, and current price)

Select the _traded today_ column, and click on the _,0_ icon (apply commas), and make it

right justify.

Also, you can change any attributes of field by opening its property palette. To open an

object_s property palette, right click on it and select the Property Palette option.

Right click on the "trade date" column and open its "property palette."

Selecting the Table in database

Additional Experiments :

1. To write a packages that use the overloading feature

Overloading

• Enables you to use the same name for different subprograms inside a PL/SQL block, asubprogram, or a

package

• Requires the formal parameters of the subprograms to differ in number, order, or datatype family

• Enables you to build more flexibility because a user or application is not restricted by the specific data

type or number of formal parameters

Overloading: Example

CREATE OR REPLACE PACKAGE over_packIS

PROCEDURE add_dept

(p_deptno IN departments.department_id%TYPE,

p_name IN departments.department_name%TYPE

DEFAULT 'unknown',

p_loc IN departments.location_id%TYPE DEFAULT 0);

PROCEDURE add_dept

(p_name IN departments.department_name%TYPE

DEFAULT 'unknown',

p_loc IN departments.location_id%TYPE DEFAULT 0);

END over_pack;

Overloading Example (continued)

If you call ADD_DEPT with an explicitly provided department ID, PL/SQL uses the first version of

theprocedure. If you call ADD_DEPT with no department ID, PL/SQL uses the second version.

EXECUTE over_pack.add_dept (980,'Education',2500)

EXECUTE over_pack.add_dept ('Training', 2400)

SELECT * FROM departments

WHERE department_id = 980;

SELECT * FROM departments

WHERE department_name = 'Training';

2. To Controlling the Persistent State of a Package Cursor

CREATE OR REPLACE PACKAGE BODY pack_cur IS

v_empno NUMBER;

PROCEDURE proc1_3rows IS

BEGIN

OPEN c1;

LOOP

FETCH c1 INTO v_empno;

DBMS_OUTPUT.PUT_LINE('Id :' ||(v_empno));

EXIT WHEN c1%ROWCOUNT >= 3;

END LOOP;

END proc1_3rows;

PROCEDURE proc4_6rows IS

BEGIN

LOOP

FETCH c1 INTO v_empno;

DBMS_OUTPUT.PUT_LINE('Id :' ||(v_empno));

EXIT WHEN c1%ROWCOUNT >= 6;

END LOOP;

CLOSE c1;

END proc4_6rows;

END pack_cur;

The slide on this page shows the package body for PACK_CUR to support the package specification.

In the package body:

1. Open the cursor and fetch successive rows from the cursor by using one packaged procedure,

PROC1_3ROWS.

2. Continue to fetch successive rows from the cursor and close the cursor, using another

packaged procedure, PROC4_6ROWS.

SET SERVEROUTPUT ON

EXECUTE pack_cur.proc1_3rows

EXECUTE pack_cur.proc4_6rows

3. Create a table called PERSONNEL. The table contains the following attributes and data types:

Column Name Data Type Length

Id Number 6

last_name VARCHAR2 35

review CLOB N/A

picture BLOB N/A

CREATE TABLE personnel

(id NUMBER(6) constraint personnel_id_pk PRIMARY KEY,

last_nameVARCHAR2(35),

review CLOB,

picture BLOB);

a) Insert two rows into the PERSONNEL table

Insert two rows into the PERSONNEL table, one each for employees 2034 and 2035. Use the empty

function for the CLOB, and provide NULL as the value for the BLOB.

INSERT INTO personnel

VALUES(2034, 'Allen', EMPTY_CLOB(), NULL);

INSERT INTO personnel

VALUES(2035, 'Bond', EMPTY_CLOB(), NULL);

b) Update the PERSONNEL table.

a. Populate the CLOB for the first row, using the following query in a SQL UPDATE statement:

SELECT ann_review

FROM review_table

WHERE employee_id = 2034;

UPDATE personnel

SET review = (SELECT ann_review

FROM review_table

WHERE employee_id = 2034)

WHERE last_name = 'Allen';

Update the PERSONNEL table.

a. Populate the CLOB for the first row, using the following query in a SQL UPDATE

statement:

SELECT ann_review

FROM review_table

WHERE employee_id = 2034;

UPDATE personnel

SET review = (SELECT ann_review

FROM review_table

WHERE employee_id = 2034)

WHERE last_name = 'Allen';

b. Populate the CLOB for the second row, using PL/SQL and the DBMS_LOB package.

Use the following SELECT statement to provide a value:

SELECT ann_review

FROM review_table

WHERE employee_id = 2035;

4. Create a procedure called DROP_TABLE2 that drops the table specified in the inputparameter.

Use the EXECUTE IMMEDIATE statement.

Create another procedure called DROP_TABLE2 that drops the table specified in the input

parameter. Use the EXECUTE IMMEDIATE statement.

CREATE PROCEDURE DROP_TABLE2

(p_table_name IN VARCHAR2)

IS

BEGIN

EXECUTE IMMEDIATE 'DROP TABLE ' || p_table_name;

END;

/

b. Repeat the test outlined in steps 1b and 1c.

CREATE TABLE emp_dup AS

SELECT * FROM employees;

EXECUTE drop_table2('emp_dup')

SELECT * FROM emp_dup;

5. Write about Oracle-Supplied Packages Oracle-Supplied Packages

• DBMS_ALERT

• DBMS_APPLICATION_INFO

• DBMS_DESCRIBE

• DBMS_LOCK

• DBMS_SESSION

Other Oracle-supplied packages include:

• DBMS_SHARED_POOL

• DBMS_TRANSACTION

• DBMS_UTILITY

Using Oracle-Supplied Packages

Package Description

DBMS_ALERT Provides notification of database events

DBMS_APPLICATION_INFO Allows application tools and application developers to inform the

database of the high level of actions they are currently performing

DBMS_DESCRIBE Returns a description of the arguments for a stored procedure

DBMS_LOCK Requests, converts, and releases userlocks, which are managed by

the RDBMS lock management services

DBMS_SESSION Provides access to SQL session information

DBMS_SHARED_POOL Keeps objects in shared memory

DBMS_TRANSACTION Controls logical transactions and improves the performance of short, no

distributed transactions

DBMS_UTILITY Analyzes objects in a particular schema, checks whether the server

is running in parallel mode, and returns the time

6. Create a procedure called ADD_JOB to insert a new job into the JOBS table. Provide the ID and title of

the job, using two parameters.

CREATE OR REPLACE PROCEDURE add_job

(p_jobid IN jobs.job_id%TYPE, p_jobtitle IN jobs.job_title%TYPE)

IS

BEGIN INSERT INTO jobs (job_id, job_title)

VALUES (p_jobid, p_jobtitle);

COMMIT;

END add_job;