This sessions is all about What is JDBC(Java Database Connectivity), What is the architecture Of JDBC , shares few JDBC performance tips etc.

1. Overview of JDBC(Java Database
Connectivity)
By Madhusmita Pradhan

2. Agenda
What is JDBC(Java Database Connectivity)
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Architecture Of JDBC
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Walk you through some JDBC basics
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Few JDBC performance tips
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3. What is JDBC ?
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JDBC keep things simple and makes database access
easy.
Standardized SQL lets you talk to databases from
different vendors in a uniform way.
The java.sql calls go through a JDBC driver.
DB vendors are creating native JDBC drivers.

4. JDBC Architecture
Application
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JDBC
Driver
Java code calls JDBC library
JDBC loads a driver
Driver talks to a particular database
Can have more than one driver -> more than one
database
Ideal: can change database engines without changing
any application code

5. JDBC Drivers
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Type I: “Bridge”
Type II: “Native”
Type III: “Middleware”
Type IV: “Pure”

6. JDBC Drivers
Type I
“Bridge”
Type II
“Native”
ODBC
ODBC
Driver
CLI (.lib)
JDBC
Type III
“Middleware”
Type IV
“Pure”
Middleware
Server

7. Transaction
Transaction = more than one statement which must all
succeed (or all fail) together
If one fails, the system must reverse all previous actions
Also can’t leave DB in inconsistent state halfway through a
transaction
COMMIT = complete transaction
ROLLBACK = abort

8. Establish Connection
JDBC application connects to a target data source
using one of two classes:
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DriverManager (Fully implemented class):
Automatically loads any JDBC 4.0 drivers found within the
class path, when this class first attempts to establish a
connection using database URL. Application must manually
load any JDBC drivers prior to version 4.0.
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DataSource (Interface): A DataSource object represents
a particular DBMS. Objects instantiated by classes that
implement the DataSource represent a particular DBMS.

9. JDBC Class Usage
Loads, chooses drivers
DriverManager / DataSource
Connects to actual database
Driver
Connection
a single SQL statement
connection session
Statement
ResultSet
the records returned from a Statement

10. Database Connection URLs
Syntax: jdbc:subprotocol:source
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Each driver has its own subprotocol
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Each subprotocol has its own syntax for the source
For MySQL:
jdbc:mysql://localhost:3306/TestDB

11. Connection using DriverManager
Class.forName("com.mysql.jdbc.Driver"); // Only for JDBC
version prior to 4.0
Connection conn =
DriverManager.getConnection("jdbc:mysql://localhost:3306/
test","root", "mindfire");

12. Connection using DataSource
Context context = new InitialContext();
DataSource dataSource = (DataSource)
context.lookup("jdbc/DataSource");
Connection connection = dataSource.getConnection();
// Here JNDI has been used for register a DataSource

13. Advantages of Using DataSource Object
Programmers no longer have to hard code the driver name or
JDBC URL in their applications, which makes them more
portable.
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DataSource properties make maintaining code much simpler
in terms of maintenance
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Includes additional implementations like ConnectionPooling
and Distributed Transactions.
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14. Statement Methods
ResultSet executeQuery(String)
Execute a SQL statement that returns a single ResultSet.
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int executeUpdate(String)
Execute a SQL INSERT, UPDATE or DELETE statement.
Returns the number of rows changed.
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boolean execute(String)
Execute a SQL statement that may return multiple results.
Statement.getMoreResults(), used for fetch next available
ResultSet, if any return true otherwise return false.
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Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery(query);

15. Statement Methods (Cont.)
If you want to execute a Statement object many times, it
usually reduces execution time to use a PreparedStatement
object instead.
When the PreparedStatement is executed, the DBMS can just
run the PreparedStatement SQL statement without having to
compile it first.
PreparedStatement stmt = con.prepareStatement(SQLQueryString);
ResultSet rs = stmt.executeQuery();

16. ResultSet
A ResultSet object is a table of data representing a database
result set, which is usually generated by executing a
statement that queries the database.
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Access data in ResultSet object through cursor(Not database
cursor). This cursor is a pointer that points to one row in a
resultset.
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Only one ResultSet per Statement can be open at once.
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A ResultSet object is automatically closed when the
Statement object that generated it is closed, re-executed,or
used to retrieve the next result from a sequence of multiple
results.
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17. ResultSet Characteristics
ResultSet Type:
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TYPE_FORWARD_ONLY(Default): cannot be scrolled, its
cursor moves forward only.
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TYPE_SCROLL_INSENSITIVE: result can be scrolled, its
cursor can move both forward and backward relative to the
current position, and it can move to an absolute position. The
result set is insensitive to changes made to the underlying
data source while it is open.
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TYPE_SCROLL_SENSITIVE: result can be scrolled, its
cursor can move both forward and backward relative to the
current position, and it can move to an absolute position. The
result set reflects changes made to the underlying data source
while the result set remains open.

18. ResultSet Characteristics (Cont.)
ResultSet Concurrency:
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CONCUR_READ_ONLY(Default): The ResultSet object
cannot be updated.
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CONCUR_UPDATABLE: The ResultSet object can be
updated.
NOTE: Not all JDBC drivers and databases support
concurrency.
DatabaseMetaData.supportsResultSetConcurrency(), method
can be used for this purpose.

19. ResultSet Characteristics (Cont.)
ResultSet Holdability: ResultSet property holdability gives
the application control over whether ResultSet objects
(cursors) are closed when commit is called.
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HOLD_CURSORS_OVER_COMMIT: ResultSet cursors
are not closed; they are holdable: they are held open when the
method commit is called. Holdable cursors might be ideal if
your application uses mostly read-only ResultSet objects.
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CLOSE_CURSORS_AT_COMMIT: ResultSet objects
(cursors) are closed when the commit method is called.
Closing cursors when this method is called can result in
better performance for some applications.
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20. Batch Update
For execute list of associate commands that may contain
statements for update, insert, or delete a row; and it may also
contain DDL statements such as CREATE TABLE and
DROP TABLE.
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con.setAutoCommit(false);
PreparedStatement pstmt = con.prepareStatement("INSERT INTO
products VALUES( ?)");
pstmt.setString(1, "Amaretto");
pstmt.addBatch();
pstmt.setString(1, "Hazelnut");
pstmt.addBatch();
// ... and so on for each new
int [] updateCounts = pstmt.executeBatch();
con.commit();

21. Performance Tips
Use PreparedStatement
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Use Batch Update
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Disable auto-commit
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Always close Statement, PreparedStatement and Connection
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Choose suitable(latest) JDBC driver because it directly
effects the performance at DAO layer.
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22. Thank You