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 = DriverManager.getConnection("jdbc:oracle:thin:FOUNDATION_PUB/XX@cerndb1"); 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” Oracle Tools and Bindings with languages

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) Oracle Tools and Bindings with languages

jdbc:oracle:thin:FOUNDATION_PUB/XX@cerndb1 Connection Details jdbc:oracle:thin:FOUNDATION_PUB/XX@cerndb1 Driver Type Username/password (optional) Connect string Connect string variants 1. @pdb2-v.cern.ch:1574/PDB_CERNDB1.cern.ch (no support for clustering, needs changing) 2. @(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)))) (long, needs changing after DB migration) 3. @cerndb1 (since 10.2.0.1.0, 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)))) Oracle Tools and Bindings with languages

Basic JDBC Use import java.sql.*; … Class.forName("oracle.jdbc.driver.OracleDriver"); System.setProperty("oracle.net.tns_admin", "G://Applications//Oracle//ADMIN"); Connection conn = DriverManager.getConnection("jdbc:oracle:thin:FOUNDATION_PUB/XX@cerndb1"); 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 … Oracle Tools and Bindings with languages

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 Oracle Tools and Bindings with languages

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, 123456); 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 Oracle Tools and Bindings with languages

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 Oracle Tools and Bindings with languages

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 Oracle Tools and Bindings with languages

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%'" dataSource="jdbc:oracle:thin:FOUNDATION_PUB/XX@cerndb1"/> <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: http://webservices.web.cern.ch/ Oracle Tools and Bindings with languages

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 Oracle Tools and Bindings with languages

Further Information E-mail: Rostislav.Titov@cern.ch Oracle Database JDBC Developer's Guide and Reference: http://docs.oracle.com/cd/B28359_01/java.111/b31224/toc.htm Oracle Tools and Bindings with languages