Chapter Seven- JDBC.pptx

Chapter 7
Java Database Connectivity (JDBC)
1 Compiled By Mikiyas D.

Outline
 Database Systems – an Introduction
 Structured Query Language
 Installing and setting up JDBC
 Basic JDBC Programming concepts
 Populating a database
 Executing Queries

Introduction
3
 What is Database ?
 The database is a collection of inter-related data which is used to retrieve,
insert and delete the data efficiently.
 It is also used to organize the data in the form of a table, schema, views,
and reports, etc.
 What is Database Management System ?
 Database management system is a software which is used to manage the
database. For example: MySQL, Oracle, etc are a very popular commercial
database which is used in different applications.
 DBMS provides an interface to perform various operations like database
creation, storing data in it, updating data, creating a table in the database
and a lot more.
Compiled By Mikiyas D.

4
 SQL is a short-form of the structured query language
 This database language is mainly designed for maintaining the data in
relational database management systems.
 It is a special tool used by data professionals for handling structured data
(data which is stored in the form of tables).
 Types of SQL Commands
 Data Definition Language (DDL)
 Data Manipulation Language (DML)
 Data Query Language (DQL)
Structured Query Language (SQL)

5
 Data Definition Language (DDL)
 DDL changes the structure of the table like creating a table, deleting a
table, altering a table, etc.
 Here are some commands that come under DDL:
 CREATE It is used to create a new table in the database.
 Syntax:
 CREATE TABLE TABLE_NAME (COLUMN_NAME DATATYPES[,....]);
 Example:
 CREATE TABLE EMPLOYEE(Name VARCHAR2(20), Email VARCHAR2(100), D
OB DATE);
Cont’d….

6
 DROP: It is used to delete both the structure and record stored in the
table.
 Syntax:
DROP TABLE table_name;
 Example:
DROP TABLE EMPLOYEE;
 ALTER: It is used to alter the structure of the database. This change could
be either to modify the characteristics of an existing attribute or probably
to add a new attribute.
 Syntax: To add a new column in the table
ALTER TABLE table_name ADD column_name COLUMN-definition;
Cont’d….

7
 Syntax: To modify existing column in the table
ALTER TABLE table_name MODIFY(column_definitions....);
 Example:
ALTER TABLE STU_DETAILS ADD(ADDRESS VARCHAR2(20));
ALTER TABLE STU_DETAILS MODIFY (NAME VARCHAR2(20));
Cont’d….

8
 Data Manipulation Language (DML)
 DML commands are used to modify the database. It is responsible for all
form of changes in the database.
 Here are some commands that come under DML:
 INSERT: The INSERT statement is a SQL query. It is used to insert data
into the row of a table.
 Syntax:
INSERT INTO TABLE_NAME (col1, col2, col3,.... col N) VALUES (value1, value2, value3, .... valueN); or
INSERT INTO TABLE_NAME VALUES (value1, value2, value3, .... valueN);
 Example:
INSERT INTO Student (Name, Id) VALUES (“Han", “R1234/23");
Cont’d….

9
 UPDATE: This command is used to update or modify the value of a column in
the table.
 Syntax:
UPDATE table_name SET [column_name1= value1,...column_nameN = valueN] [WHERE CONDITION]
 Example:
UPDATE student SET Name = ’Hana’ WHERE Id = “R1234/23";
 DELETE: It is used to remove one or more row from a table.
 Syntax:
DELETE FROM table_name [WHERE condition];
 Example:
DELETE FROM Student WHERE Id=" R1234/23";
Cont’d….

10
 Data Query Language (DQL)
 DQL is used to fetch the data from the database.
 It uses only one command: select
 SELECT: This is the same as the projection operation of relational algebra.
It is used to select the attribute based on the condition described by
WHERE clause.
 Syntax:
SELECT expressions FROM TABLE_NAME WHERE conditions;
 Example:
SELECT emp_name FROM employee WHERE age > 20;
Cont’d….

Introduction to JDBC
11
 JDBC is a Java API to connect and execute the query with the
database.
 JDBC API uses JDBC drivers to connect with the database.
 We can use JDBC API to access tabular data stored in any relational
database.
 By the help of JDBC API, we can save, update, delete and fetch data
from the database.
 The java.sql package contains classes and interfaces for JDBC API.

JDBC Architecture

JDBC Architecture (cont.)
Application JDBC Driver
 Java code calls JDBC library
 JDBC loads a driver
 Driver talks to a particular database
 An application can work with several databases by using
all corresponding drivers

JDBC Steps…..
14
 There are 5 steps to connect any java application with
the database using JDBC. These steps are as follows:
 Register the Driver class
 Create connection
 Create statement
 Execute queries
 Close connection

JDBC Steps…..
15
 Step 1: Register the driver class
 The forName() method of Class is used to register the driver class.
 This method is used to dynamically load the driver class.
 Example
 Class.forName(“com.mysql.jdbc.Driver ”);
 Step 2: Create the connection object
 The getConnection() method of DriverManager class is used to establish
connection with the database.

Cont’d…….
16
 Syntax for Creating Connection
1. public static Connection getConnection(String url)throws SQLExcept
ion
2. public static Connection getConnection(String url,String name,String
password) throws SQLException
 Example:
Connection con=DriverManager.getConnection(
"jdbc:mysql://localhost:3306/miki ",“root","password");

Cont’d…….
17
 Step 3: Create the Statement object
 The createStatement() method of Connection interface is used to create
statement.
 The object of statement is responsible to execute queries with the
database.
 Syntax of createStatement() method
public Statement createStatement() throws SQLException
 Example
 Statement stmt=con.createStatement();
 or

Cont’d…….
18
 Creating prepared Statement
 Syntax:
 PreparedStatement pstmt=connObj.prepareStatement(sql);
 Example:
 PreparedStatement pStmt = conn.prepareStatement("UPDATE
Sells SET price = ? WHERE bar = ? AND beer = ?");
pStmt.setDouble(1,58);
pStmt.setString(2,”Hilten”);
pStmt.setString(3,”Heinken”);
 Why use PreparedStatement?
 Improves performance: The performance of the application will be faster if
you use PreparedStatement interface because query is compiled only once

Cont’d…….
19
 Step 4: Execute the Statement
 executeQuery(): executes a simple SELECT query and returns a single ResultSet object
 executeUpdate(): executes the SQL INSERT, UPDATE, and DELETE statement, and
 Example: pStmt.executeUpdate(); //executes the sql in the previous slide
 executeQuery method returns the object of ResultSet that can be used to
get all the records of a table.
 Syntax of executeQuery() method
public ResultSet executeQuery(String sql) throws SQLException
 Example

Cont’d…….
20
 Step 5: Close the connection object
 By closing connection object Statement and ResultSet will be closed
automatically.
 The close() method of Connection interface is used to close the connection.
 Syntax of close() method
public void close() throws SQLException
 Example
con.close();

Connecting to MYSQL Database Example
21
 First download MYSQL JDBC connector/Driver on the link:
https://dev.mysql.com/downloads/connector/j/5.1.html
 Then on NetBeans create New Project, goto the project you Created, Right
click on the Library, Click on Add JAR/Folder, then locate the path where
you place your MYSQL Connector, and add it to the library.

Cont’d………..

Cont’d…….
23
 Create Database and Tables on MYSQL, then

Cont’d…….

Chapter Seven- JDBC.pptx

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Chapter Seven- JDBC.pptx