Jdbc drivers

242-301 Adv. CoE Lab: JDBC 1
• Objective
– to give some background on JDBC to
help with the lab exercises
Introduction to Java
Database Connectivity
(JDBC)

Overview
1. What is JDBC?
2. The JDBC-ODBC Bridge
3. Four Types of JDBC Drivers
4. JDBC Pseudocode
5. SimpleJDBC.java
Continued

6. Meta Data
7. Using MS Access
8. Books.accdb as an ODBC
Data Source
9. Data Source Problems
10. More Information

1. What is JDBC?
• JDBC is an interface which allows Java
code to execute SQL statements inside relati
onal databases
– the databases must follow the ANSI SQL-2
standard

JDBC in Use
Java
program
connectivity
data processing
utilities
JDBC
driver
for Oracle
driver
for Sybase
jdbc-odbc
bridge
odbc
driver
Green means
"Java code"

2. The JDBC-ODBC Bridge
• ODBC (Open Database Connectivity) is a
Microsoft standard from the mid 1990’s.
• It is an API that allows C/C++ programs to
execute SQL inside databases
• ODBC is supported by many products.
Continued

• The JDBC-ODBC bridge allows Java code
to use the C/C++ interface of ODBC
– it means that JDBC can access many different
database products
• The layers of translation (Java --> C -->
SQL) can slow down execution.
Continued

• The JDBC-ODBC bridge comes free with
the JDK:
– called sun.jdbc.odbc.JdbcOdbcDriver
• The ODBC driver for Microsoft Access
comes with MS Office
– so it is easy to connect Java and Access

3. Four Types of JDBC Driver
• 1. JDBC-ODBC Bridge (type 1)
– translate Java to the ODBC API
– used by many Windows-based databases, e.g.
MS-Access
• 2. Database Protocol Driver (type 4)
– Independent from the OS/hardware because the
driver is in Java.
Continued

• 3. Native API Connection Driver (type 2)
– connected by a OS native module, dependent
on the OS or hardware
(e.g. DLLs on Windows)
• 4. Net Connection Driver (type 3)
– use Java to access the database via networking
middleware (usually TCP/IP)
– required for networked applications

JDBC Drivers
• A very long list of drivers (freeware,
shareware, and commercial) can be found at
:
http://www.oracle.com/technetwork/java/
index-136695.html

4. JDBC as a Diagram
DriveManager Connection Statement ResultSet
creates creates creates
Driver
SQL
SQL
data
data
make link
to driver
Green means
"Java code"

DriveManager
• It is responsible for establishing the
connection to the database through the driver
.
• e.g.
Class.forName(
"sun.jdbc.odbc.JdbcOdbcDriver");
Connection conn =
DriveManager.getConnection(url);
name of the database

Name the Database
• The name and location of the database is
given as a URL
– the details of the URL vary depending on the
type of database that is being used

ODBC Database URL
jdbc:odbc: //host.domain.com: 2048 /data/file
The comms
protocol
The machine
holding the
database.
The port
used for the
connection.
The path to
the database
on the machine
e.g. jdbc:odbc:Books

Statement Object
• The Statement object provides a
‘workspace’ where SQL queries can be crea
ted, executed, and results collected.
• e.g.
Statement st =
conn.createStatement():
ResultSet rs = st.executeQuery(
“ select * from Authors” );
:
st.close();

ResultSet Object
• Stores the results of a SQL query.
• A ResultSet object is similar to a
‘table’ of answers, which can be examine
d by moving a ‘pointer’ (cursor).
Continued

• Cursor operations:
– first(), last(), next(), previous(), etc.
• Typical code:
while( rs.next() ) {
// process the row;
}
23
5
17
98
John
Mark
Paul
Peter
cursor

5. SimpleJDBC.java
// SimpleJDBC.java
// Displays the firstnames and lastnames
// of the Authors table in the Books db.
import java.sql.*;
public class SimpleJDBC {
public static void main(String[] args)
{
// The URL for the Books database.
// ’Protected' by a login and password.
String url = "jdbc:odbc:Books";
String username = "anonymous";
String password = "guest";
:

try {
// load the JDBC-ODBC Bridge driver
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
// connect to db using DriverManager
Connection conn =
DriverManager.getConnection( url,
username, password );
// Create a statement object
Statement statement = conn.createStatement();
// Execute the SQL query
ResultSet rs = statement.executeQuery(
"SELECT lastName, firstName FROM
Authors" );
:

// Print the result set
while( rs.next() )
System.out.println(
rs.getString("lastName") + ", " +
rs.getString("firstName") );
// Close down
statement.close();
conn.close();
}
:

catch ( ClassNotFoundException cnfex ) {
System.err.println(
"Failed to load JDBC/ODBC driver." );
cnfex.printStackTrace();
System.exit( 1 ); // terminate program
}
catch ( SQLException sqlex ) {
System.err.println( sqlex );
sqlex.printStackTrace();
}
} // end of main()
} // end of SimpleJDBC class

Section 8
not done.
Section 8
now done.
Output

• If you've done section 8, but still gettingIf you've done section 8, but still getting
error messages, then check out section 9.error messages, then check out section 9.
• If you're still having problems, please comeIf you're still having problems, please come
to see Aj. Andrew.to see Aj. Andrew.

5.1. Username & Password
• The database’s link to the outside (e.g. its
ODBC interface) must be configured to hav
e a login and password
– details for ODBC are given later

5.2. Accessing a ResultSet
• The ResultSet class contains many
methods for accessing the value of a
column of the current row
– can use the column name or position
– e.g. get the value in the lastName column:
rs.getString("lastName")
Continued

• The ‘tricky’ aspect is that the values are
SQL data, and so must be converted to Java
types/objects.
• There are many methods for accessing/
converting the data, e.g.
– getString(), getDate(), getInt(),
getFloat(), getObject()

6. Meta Data
• Meta data is the information about the
database:
– e.g. the number of columns, the types of the
columns
– meta data is the schema information
ID Name Course Mark
007 James Bond Shooting 99
008 Aj. Andrew Kung Fu 1
meta data

• One important use for metadata is forOne important use for metadata is for
formatting result set dataformatting result set data
– e.g. instead of displaying the results as text,e.g. instead of displaying the results as text,
display them in a Java table with headers, rows,display them in a Java table with headers, rows,
columnscolumns
• see TableDisplay.java in the Exercisessee TableDisplay.java in the Exercises

6.1. Accessing Meta Data
• The getMetaData() method can be used
on a ResultSet object to create its meta da
ta object.
• e.g.
ResultSetMetaData md =
rs.getMetaData();

6.2. Using Meta Data
int numCols = md.getColumnCount();
for (int i = 0; i <= numCols; i++) {
if (md.getColumnType(i) ==
Types.CHAR)
System.out.println(
md.getColumnName(i) )
}

6.3. More Meta Data Methods
• getTableName()
• getPrecision()
– number of decimal digits in the column
• isSigned()
– returns true if column has signed numbers
• isCurrency()
• etc.

7. Using MS Access7. Using MS Access
• MS Access changed its file formats whenMS Access changed its file formats when
Access 2007 was released:Access 2007 was released:
– for Access 2003 (and earlier) you should usefor Access 2003 (and earlier) you should use
Books.Books.mdbmdb
– for Access 2007 or 2010, you should usefor Access 2007 or 2010, you should use
Books.Books.accdbaccdb
– both versions are in the lab's website.both versions are in the lab's website.

Access and SQLAccess and SQL
• How to use SQL in Access is described at:How to use SQL in Access is described at:
– http://www.jaffainc.com/SQLStatementsInAccess.htmhttp://www.jaffainc.com/SQLStatementsInAccess.htm
And on the
website, in
sqlAccess2007
.txt and
sql_intr.pdf
And on the
website, in
sqlAccess2007
.txt and
sql_intr.pdf

TableRelationships in Books.accdb
(and Books.mdb)
Under Database Tools > Relationships

8. Books.accdb as an ODBC Data Source
• 1. Click on
“Data Sources
(ODBC)” in
“Administrative
Tools” folder in
the Control
Panel.

• Select the MS Access Data Source.Select the MS Access Data Source.
Press “Add’ to add a data source.
If you don't find
MS Access here,
then go to
Section 9.

• Select the English
Microsoft Access
Driver (*.mdb,
*.accdb).
Press “Finish”.

• 3. Type in the
"Books"
source name,
any description,
and press “Select”
to browse to set
the path to the
Books.accdb or
Books.mdb file.
Click on
“Advanced”.

• 4. Type in a username
and password (guest).
Click “Ok” repeatedly
until all the dialog
boxes are gone.

9. Data Source Problems9. Data Source Problems
• Two problems may occur when using JDBCTwo problems may occur when using JDBC
with the data source set up in Section 8:with the data source set up in Section 8:
– "No suitable driver found for jdbc: odbc:"No suitable driver found for jdbc: odbc:
driver={Microsoft Access Driver (*.mdb)};...driver={Microsoft Access Driver (*.mdb)};...
– "The specified DSN contains an architecture mismatch"The specified DSN contains an architecture mismatch
between the Driver and Application"between the Driver and Application"
• These problems are usually due to youThese problems are usually due to you
using the 64-bit version of Windows 7.using the 64-bit version of Windows 7.

• Check your version of Windows byCheck your version of Windows by
following the steps listed at:following the steps listed at:
– http://support.microsoft.com/kb/827218http://support.microsoft.com/kb/827218
means
32-bit

Which Version of Access?Which Version of Access?
• Check whether you are using the 32-bit orCheck whether you are using the 32-bit or
64-bit version of Access:64-bit version of Access:
– look at the "Help" dialoglook at the "Help" dialog

Win7 64-bit & Access 64-bitWin7 64-bit & Access 64-bit
• You may need to download the 64-bitYou may need to download the 64-bit
Access drivers from:Access drivers from:
– http://www.microsoft.com/http://www.microsoft.com/
en-us/download/details.aspx?id=13255en-us/download/details.aspx?id=13255
– executeexecute AccessDatabaseEngine_x64.exe
• You should also be using theYou should also be using the 64-bit64-bit versionversion
of Java for Windows. get it from:of Java for Windows. get it from:
– http://www.java.com/en/download/http://www.java.com/en/download/

Win 7 64-bit & AccessWin 7 64-bit & Access 32-bit32-bit
• Set up the data source using the 32-bitSet up the data source using the 32-bit
ODBC control panel at:ODBC control panel at:
– c:windowssysWOW64odbcad32.exec:windowssysWOW64odbcad32.exe
• You should also be using theYou should also be using the 32-bit32-bit versionversion
of Java for Windows. Get it from:of Java for Windows. Get it from:
– http://www.java.com/en/download/http://www.java.com/en/download/

10. More Information
• Ivor Horton’s Beginning Java 2, JDK 5
Edition, Wiley Publishing, 2005
Chapters 24 and 25 (starts on p.1306)
• Advanced Java 2 Platform: How to Program
Deitel & Deitel, Prentice-Hall, 2001
Chapter 8
http://java.coe.psu.ac.th/ForMember/
Continued

• JDBC Wikipaedia page:
• http://en.wikipedia.org/wiki/JDBC_driver
• The Java Documentation and tutorial
– http://docs.oracle.com/javase/tutorial/
– the JDBC Database Access ‘trail’ is very good
– http://docs.oracle.com/javase/tutorial/
jdbc/index.html

Jdbc drivers

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Jdbc drivers