1. Basic JDBC Use Oracle JDBC Drivers must be in the CLASSPATH
import java.sql.*; …
Class.forName("oracle.jdbc.driver.OracleDriver");
System.setProperty("oracle.net.tns_admin", "G://Applications//Oracle//ADMIN");
Connection conn =
Statement stmt = conn.createStatement();
ResultSet rset = stmt.executeQuery("Select LAST_NAME from PERSONS where ORG_UNIT like 'IT%'");
while (rset.next())
System.out.println(rset.getString("LAST_NAME"));
rset.close();
stmt.close();
conn.close();
Load the Oracle JDBC driver
Set which TNSNAMES file to use
Create statement
Specify the connection
Execute query
Obtain results
Clean up
Oracle JDBC Drivers must be in the CLASSPATH
Preinstalled in the CERN Web Services infrastructure (thin)
Obtaining drivers: Google for “Oracle JDBC Drivers”
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2. Oracle JDBC Driver Types
Thin driver (works through TCP/IP)
Pure Java
Platform independent
Does not require Oracle Client Installation
Can be used in applets
OCI driver (works through SQL*Net)
Better performance
Support OCI connection pooling
Caching results in the client’s memory
Requires Oracle Client Installation
Should match the database version
Platform specific
Server-side internal driver (Java stored procedures)
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3. jdbc:oracle:thin:FOUNDATION_PUB/XX@cerndb1
Connection Details
Driver Type
Username/password (optional)
Connect string
Connect string variants
(no support for clustering, needs changing)
(ADDRESS= (PROTOCOL=TCP) (HOST=pdb2-v.cern.ch) (PORT=1574) ) (ADDRESS= (PROTOCOL=TCP) (HOST=pdb1-v.cern.ch) (PORT=1574) )(FAILOVER=on) (LOAD_BALANCE=off)(CONNECT_DATA= (SERVER=DEDICATED) (SERVICE_NAME=PDB_CERNDB1.cern.ch)(FAILOVER_MODE= (TYPE=SELECT) (METHOD=BASIC))))
(long, needs changing after DB migration)
(since , requires oracle.net.tns_admin property)
TNSNAMES.ORA entry example
cerndb1=(DESCRIPTION=(ADDRESS= (PROTOCOL=TCP) (HOST=pdb2-v.cern.ch) (PORT=1574) ) (ADDRESS= (PROTOCOL=TCP) (HOST=pdb1-v.cern.ch) (PORT=1574) ) (FAILOVER=on)(LOAD_BALANCE=off) (CONNECT_DATA= (SERVER=DEDICATED) (SERVICE_NAME=PDB_CERNDB1.cern.ch) (FAILOVER_MODE= (TYPE=SELECT) (METHOD=BASIC))))
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4. Basic JDBC Use
import java.sql.*; …
Class.forName("oracle.jdbc.driver.OracleDriver");
System.setProperty("oracle.net.tns_admin", "G://Applications//Oracle//ADMIN");
Connection conn =
Statement stmt = conn.createStatement();
ResultSet rset = stmt.executeQuery("Select LAST_NAME from PERSONS where ORG_UNIT like 'IT%'");
while (rset.next())
System.out.println(rset.getString("LAST_NAME"));
rset.close();
stmt.close();
conn.close();
Load the Oracle JDBC driver
Set which TNSNAMES file to use
Create statement
Specify the connection
Execute query
Obtain results
Clean up
The property can also be specified (or overridden) via the command line:
java -Doracle.net.tns_admin=G:\Applications\Oracle\Admin …
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5. Use of Prepared Statements
PreparedStatement stmt = conn.prepareStatement("Select LAST_NAME from PERSONS where ORG_UNIT = ? and FIRST_NAME = ?");
stmt.setString(1, "IT"); stmt.setString(2, "EVA");
ResultsSet rset = stmt.executeQuery();
Better performance (no query re-parsing)
Protect from SQL injection
Use whenever possible
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6. Calling PL/SQL from Java
// Function
CallableStatement stmt = conn.prepareCall("{?= call supervisor.team_leader(?, ?, ?)}");
// Procedure
CallableStatement stmt2 = conn.prepareCall("{call supervisor.team_leader(?, ?, ?)}");
stmt.registerOutParameter(1, Types.NUMERIC); stmt.registerOutParameter(4, Types.VARCHAR);
stmt.setInt(2, );
stmt.setDate(3, new java.sql.Date((new java.util.Date()).getTime()));
stmt.execute();
System.out.println(stmt.getInt(1));
System.out.println(stmt.getString(4));
package supervisor
function team_leader(institute in varchar,
date in date, result out varchar)
All OUT and INOUT parameters have to be registered
Indices start from 1
In case of a function, the first parameter is the result
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7. conn.setAutoCommit(false/true);
Commits and rollbacks
conn.setAutoCommit(false/true);
true - statements are committed individually
false - statements are grouped until commit() or rollback()
conn.commit();
Commit the current transaction and release DB locks
conn.rollback();
Rollback (undo) the current transaction
conn.rollback(savepoint);
Undo the changes made after the given save point
N.B. Auto-commit is switched ON by default
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8. Proper Exception Handling
JDK 1.7
JDK < 1.7
try (
Connection conn = …;
PreparedStatement stmt = … ;
ResultSet rset = … ;
) {
// Some database operations }
catch (Exception e) {
// Handle the exception (e.g. logging)
Connection conn = null;
PreparedStatement stmt = null;
ResultSet rset = null;
try {
// Some database operations }
catch (Exception e)
// Handle the exception (e.g. logging)
finally
if (rset != null) rset.close();
if (stmt != null) stmt.close();
if (conn != null) conn.close():
IF NOT:
Run out of connections
Run out of database sessions
May crash both yours and other apps running on the database
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9. JSP Example (using JSTL)
page contentType="text/html;charset=windows-1252"%>
taglib prefix="c" uri="/WEB-INF/tlds/c.tld"%>
taglib prefix="sql" uri="/WEB-INF/tlds/sql.tld"%>
<html>
<body>
<sql:query var="result"
sql="Select FIRST_NAME, LAST_NAME from PERSONS where ORG_UNIT like 'IT%'"
<table>
<tr><th>First name</th><th>Last Name</th></tr>
<c:forEach items="${result.rows}" var="row">
<tr><td>${row.FIRST_NAME}</td><td>${row.LAST_NAME}</td>
</c:forEach>
</table>
</body>
</html>
JSP = Java Server Pages
JSTL = JSP Standard Tag Library
CERN Java Web Hosting:
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10. Beyond simple JDBC javax.sql.* package
DataSource, connection pooling, distributed transactions
Lightweight connection pools (e.g. c3p0)
Opening a connection is costly -> reuse!
Use pooling for extensive DB use
JDBC Abstraction Frameworks (e.g. Spring JDBC)
Simplify use of JDBC
Object Relational Mappers (e.g. Hibernate)
Map Java objects to database tables
Handle object relationships
Save/load complex objects with a single command
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11. Further Information E-mail: Rostislav.Titov@cern.ch
Oracle Database JDBC Developer's Guide and Reference:
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