8 Data Sources and URLs

This chapter discusses connecting applications to databases using Java Database Connectivity (JDBC) data sources, as well as the URLs that describe databases. This chapter contains the following sections:

8.1 About Data Sources

Data sources are standard, general-use objects for specifying databases or other resources to use. The JDBC 2.0 extension application programming interface (API) introduced the concept of data sources. For convenience and portability, data sources can be bound to Java Naming and Directory Interface (JNDI) entities, so that you can access databases by logical names.

The data source facility provides a complete replacement for the previous JDBC DriverManager facility. You can use both facilities in the same application, but it is recommended that you transition your application to data sources.

This section covers the following topics:

8.1.1 Overview of Oracle Data Source Support for JNDI

The JNDI standard provides a way for applications to find and access remote services and resources. These services can be any enterprise services. However, for a JDBC application, these services would include database connections and services.

JNDI enables an application to use logical names in accessing these services, removing vendor-specific syntax from application code. JNDI has the functionality to associate a logical name with a particular source for a desired service.

All Oracle JDBC data sources are JNDI-referenceable. The developer is not required to use this functionality, but accessing databases through JNDI logical names makes the code more portable.


Using JNDI functionality requires the jndi.jar file to be in the CLASSPATH environment variable. This file is included with the Java products on the installation CD. You must add it to the CLASSPATH environment variable separately.

8.1.2 Features and Properties of Data Sources

By using the data source functionality with JNDI, you do not need to register the vendor-specific JDBC driver class name and you can use logical names for URLs and other properties. This ensures that the code for opening database connections is portable to other environments.

The DataSource Interface and Oracle Implementation

A JDBC data source is an instance of a class that implements the standard javax.sql.DataSource interface:

public interface DataSource
   Connection getConnection() throws SQLException;
   Connection getConnection(String username, String password)
      throws SQLException;

Oracle implements this interface with the OracleDataSource class in the oracle.jdbc.pool package. The overloaded getConnection method returns a connection to the database.

To use other values, you can set properties using appropriate setter methods. For alternative user names and passwords, you can also use the getConnection method that takes these parameters as input. This would take priority over the property settings.


The OracleDataSource class and all subclasses implement the java.io.Serializable and javax.naming.Referenceable interfaces.

Properties of DataSource

The OracleDataSource class, as with any class that implements the DataSource interface, provides a set of properties that can be used to specify a database to connect to. These properties follow the JavaBeans design pattern.

The following tables list the OracleDataSource standard properties and Oracle extensions respectively.


Oracle does not implement the standard roleName property.

Table 8-1 Standard Data Source Properties

Name Type Description



Name of the particular database on the server.



Name of the underlying data source class. For connection pooling, this is an underlying pooled connection data source class. For distributed transactions, this is an underlying XA data source class.



Description of the data source.



Network protocol for communicating with the server. For Oracle, this applies only to the JDBC Oracle Call Interface (OCI) drivers and defaults to tcp.



Password for the connecting user.



Number of the port where the server listens for requests



Name of the database server



Name for the login


For security reasons, there is no getPassword() method.

Table 8-2 Oracle Extended Data Source Properties

Name Type Description



Specifies the name of the cache. This cannot be changed after the cache has been created.



Specifies properties for implicit connection cache.



Specifies whether implicit connection cache is in use.



Specifies the connection properties.



Specifies Oracle JDBC driver type. It can be one of oci, thin, or kprb.



Specifies whether Fast Connection Failover is in use.



Specifies whether the implicit statement connection cache is enabled.



Specifies the maximum time in seconds that this data source will wait while attempting to connect to a database.



Specifies the log writer for this data source.



Specifies the maximum number of statements in the application cache.



Specifies the database service name for this data source.



Specifies the TNS entry name. The TNS entry name corresponds to the TNS entry specified in the tnsnames.ora configuration file.

Enable this OracleXADataSource property when using the Native XA feature with the OCI driver, to access Oracle pre-8.1.6 databases and later. If the tnsEntry property is not set when using the Native XA feature, then a SQLException with error code ORA-17207 is thrown



Specifies the URL of the database connection string. Provided as a convenience, it can help you migrate from an older Oracle Database. You can use this property in place of the Oracle tnsEntry and driverType properties and the standard portNumber, networkProtocol, serverName, and databaseName properties.



Allows an OracleXADataSource using the Native XA feature with the OCI driver, to access Oracle pre-8.1.6 databases and later. If the nativeXA property is enabled, be sure to set the tnsEntry property as well. This property is only for OracleXADatasource.

This DataSource property defaults to false.



Specifies the ONS configuration string that is used to remotely subscribe to FAN/ONS events.


  • This table omits properties that supported the deprecated connection cache based on OracleConnectionCache.

  • Because Native XA performs better than Java XA, use Native XA whenever possible.

Use the setConnectionProperties method to set the properties of the connection and the setConnectionCacheProperties method to set the properties of the connection cache.

If you are using the server-side internal driver, that is, the driverType property is set to kprb, then any other property settings are ignored.

If you are using the JDBC Thin or OCI driver, then note the following:

  • A URL setting can include settings for user and password, as in the following example, in which case this takes precedence over individual user and password property settings:

  • Settings for user and password are required, either directly through the URL setting or through the getConnection call. The user and password settings in a getConnection call take precedence over any property settings.

  • If the url property is set, then any tnsEntry, driverType, portNumber, networkProtocol, serverName, and databaseName property settings are ignored.

  • If the tnsEntry property is set, which presumes the url property is not set, then any databaseName, serverName, portNumber, and networkProtocol settings are ignored.

  • If you are using an OCI driver, which presumes the driverType property is set to oci, and the networkProtocol is set to ipc, then any other property settings are ignored.

Also, note that getConnectionCacheName() will return the name of the cache only if the ConnectionCacheName property of the data source is set after caching is enabled on the data source.

8.1.3 Creating a Data Source Instance and Connecting

This section shows an example of the most basic use of a data source to connect to a database, without using JNDI functionality. Note that this requires vendor-specific, hard-coded property settings.

Create an OracleDataSource instance, initialize its connection properties as appropriate, and get a connection instance, as in the following example:

OracleDataSource ods = new OracleDataSource();
Connection conn = ods.getConnection();

Or, optionally, override the user name and password, as follows:

Connection conn = ods.getConnection("OE", "oe");

8.1.4 Creating a Data Source Instance, Registering with JNDI, and Connecting

This section exhibits JNDI functionality in using data sources to connect to a database. Vendor-specific, hard-coded property settings are required only in the portion of code that binds a data source instance to a JNDI logical name. From that point onward, you can create portable code by using the logical name in creating data sources from which you will get your connection instances.


Creating and registering data sources is typically handled by a JNDI administrator, not in a JDBC application.

Initialize Data Source Properties

Create an OracleDataSource instance, and then initialize its properties as appropriate, as in the following example:

OracleDataSource ods = new OracleDataSource();

Register the Data Source

Once you have initialized the connection properties of the OracleDataSource instance ods, as shown in the preceding example, you can register this data source instance with JNDI, as in the following example:

Context ctx = new InitialContext();
ctx.bind("jdbc/sampledb", ods);

Calling the JNDI InitialContext() constructor creates a Java object that references the initial JNDI naming context. System properties, which are not shown, instruct JNDI which service provider to use.

The ctx.bind call binds the OracleDataSource instance to a logical JNDI name. This means that anytime after the ctx.bind call, you can use the logical name jdbc/sampledb in opening a connection to the database described by the properties of the OracleDataSource instance ods. The logical name jdbc/sampledb is logically bound to this database.

The JNDI namespace has a hierarchy similar to that of a file system. In this example, the JNDI name specifies the subcontext jdbc under the root naming context and specifies the logical name sampledb within the jdbc subcontext.

The Context interface and InitialContext class are in the standard javax.naming package.


The JDBC 2.0 Specification requires that all JDBC data sources be registered in the jdbc naming subcontext of a JNDI namespace or in a child subcontext of the jdbc subcontext.

Open a Connection

To perform a lookup and open a connection to the database logically bound to the JNDI name, use the logical JNDI name. Doing this requires casting the lookup result, which is otherwise a Java Object, to OracleDataSource and then using its getConnection method to open the connection.

Here is an example:

OracleDataSource odsconn = (OracleDataSource)ctx.lookup("jdbc/sampledb");
Connection conn = odsconn.getConnection();

8.1.5 Supported Connection Properties

For a detailed list of connection properties that Oracle JDBC drivers support, see the Oracle Database JDBC Java API Reference.

8.1.6 About Using Roles for SYS Login

To specify the role for the SYS login, use the internal_logon connection property. To log on as SYS, set the internal_logon connection property to SYSDBA or SYSOPER.


The ability to specify a role is supported only for the sys user name.

For a bequeath connection, we can get a connection as SYS by setting the internal_logon property. For a remote connection, we need additional password file setting procedures.

8.1.7 Configuring Database Remote Login

Before the JDBC Thin driver can connect to the database as SYSDBA, you must configure the user, because Oracle Database security system requires a password file for remote connections as an administrator. Perform the following:

  1. Set a password file on the server-side or on the remote database, using the orapwd password utility. You can add a password file for user SYS as follows:
    • In UNIX

      orapwd file=$ORACLE_HOME/dbs/orapwORACLE_SID entries=200
      Enter password: password
    • In Microsoft Windows

      orapwd file=%ORACLE_HOME%\database\PWDORACLE_SID.ora entries=200
      Enter password: password

    In this case, file is the name of the password file, password is the password for user SYS. It can be altered using the ALTER USER statement in SQL Plus. You should set entries to a value higher than the number of entries you expect.

    The syntax for the password file name is different on Microsoft Windows and UNIX.

  2. Enable remote login as SYSDBA. This step grants SYSDBA and SYSOPER system privileges to individual users and lets them connect as themselves.

    Stop the database, and add the following line to initservice_name.ora, in UNIX, or init.ora, in Microsoft Windows:


    The initservice_name.ora file is located at ORACLE_HOME/dbs/ and also at ORACLE_HOME/admin/db_name/pfile/. Ensure that you keep the two files synchronized.

    The init.ora file is located at %ORACLE_BASE%\ADMIN\db_name\pfile\.

  3. Change the password for the SYS user. This is an optional step.
    PASSWORD sys
           Changing password for sys
    New password: password
    Retype new password: password
  4. Verify whether SYS has the SYSDBA privilege.
    SQL> select * from v$pwfile_users;
    USERNAME                         SYSDB        SYSOP
    ----------------------           ---------    ---------
    SYS                              TRUE         TRUE
  5. Restart the remote database.

Example 8-1 Using SYS Login To Make a Remote Connection

//This example works regardless of language settings of the database.
 /** case of remote connection using sys **/
import java.sql.*;
import oracle.jdbc.*;
import oracle.jdbc.pool.*;
// create an OracleDataSource
OracleDataSource ods = new OracleDataSource();
// set connection properties
java.util.Properties prop = new java.util.Properties();
prop.put("user", "sys");
prop.put("password", "sys");
prop.put("internal_logon", "sysoper");
// set the url
// the url can use oci driver as well as:
// url = "jdbc:oracle:oci8:@remotehost"; the remotehost is a remote database
String url = "jdbc:oracle:thin:@//localhost:5221/orcl";
// get the connection
Connection conn = ods.getConnection();

8.1.8 Using Bequeath Connection and SYS Logon

The following example illustrates how to use the internal_logon and SYSDBA arguments to specify the SYS login. This example works regardless of the database's national-language settings of the database.

/** Example of bequeath connection **/
import java.sql.*;
import oracle.jdbc.*;
import oracle.jdbc.pool.*;
// create an OracleDataSource instance
OracleDataSource ods = new OracleDataSource();
// set neccessary properties
java.util.Properties prop = new java.util.Properties();
prop.put("user", "sys");
prop.put("password", "sys");
prop.put("internal_logon", "sysdba");
// the url for bequeath connection
String url = "jdbc:oracle:oci8:@";
// retrieve the connection
Connection conn = ods.getConnection();

8.1.9 Setting Properties for Oracle Performance Extensions

Some of the connection properties are for use with Oracle performance extensions. Setting these properties is equivalent to using corresponding methods on the OracleConnection object, as follows:

  • Setting the defaultRowPrefetch property is equivalent to calling setDefaultRowPrefetch.

  • Setting the remarksReporting property is equivalent to calling setRemarksReporting.


The following example shows how to use the put method of the java.util.Properties class, in this case, to set Oracle performance extension parameters.

//import packages and register the driver
import java.sql.*;
import java.math.*;
import oracle.jdbc.*;
import oracle.jdbc.pool.OracleDataSource;

//specify the properties object
java.util.Properties info = new java.util.Properties();
info.put ("user", "HR");
info.put ("password", "hr");
info.put ("defaultRowPrefetch","20");
info.put ("defaultBatchValue", "5");

//specify the datasource object 
OracleDataSource ods = new OracleDataSource();

8.1.10 Support for Network Data Compression

Starting from Oracle Database 12c Release 2 (, the JDBC Thin driver supports network data compression. Network data compression reduces the size of the session data unit (SDU) transmitted over a data connection and reduces the time required to transmit a SQL query and the result across the network. The benefits are more significant in case of Wireless Area Network (WAN). For enabling network data compression, you must set the connection properties in the following way:


Network compression does not work for streamed data.

OracleDataSource ds = new OracleDataSource();
Properties prop = new Properties();

// Enabling Network Compression

//Optional configuration for setting the client compression threshold.

Connection conn = ds.getConnection();

8.2 Database URLs and Database Specifiers

Database URLs are strings. The complete URL syntax is:



  • The brackets indicate that the username/password pair is optional.

  • kprb, the internal server-side driver, uses an implicit connection. Database URLs for the server-side driver end after the driver_type.

The first part of the URL specifies which JDBC driver is to be used. The supported driver_type values are thin, oci, and kprb.

The remainder of the URL contains an optional user name and password separated by a slash, an @, and the database specifier, which uniquely identifies the database to which the application is connected. Some database specifiers are valid only for the JDBC Thin driver, some only for the JDBC OCI driver, and some for both.

8.2.1 Support for Internet Protocol Version 6

This release of Oracle JDBC drivers supports Internet Protocol Version 6 (IPv6) addresses in the JDBC URL and machine names that resolve to IPv6 addresses. IPv6 is a new Network layer protocol designed by the Internet Engineering Task Force (IETF) to replace the current version of Internet Protocol, Internet Protocol Version 4 (IPv4). The primary benefit of IPv6 is a large address space, derived from the use of 128-bit addresses. IPv6 also improves upon IPv4 in areas such as routing, network autoconfiguration, security, quality of service, and so on.


  • An IPv6 Client can support only IPv6 Servers or servers with dual protocol support, that is, support for both IPv6 and IPv4 protocols. Conversely, an IPv6 Server can support only IPv6 clients or dual protocol clients.

  • IPv6 is supported only with single instance Database servers and not with Oracle RAC.

If you want to use a literal IPv6 address in a URL, then you should enclose the literal address enclosed in a left bracket ([) and a right bracket (]). For example: [2001:0db8:7654:3210:FEDC:BA98:7654:3210]. So, a JDBC URL, using an IPv6 address will look like the following:



All the new System classes that are required for IPv6 support are loaded when Java is enabled during database initialization. So, if your application does not have any IPv6 addressing, then you do not need to change your code to use IPv6 functionality. However, if your application has either IPv6 only or both IPv6 and IPv4 addressing, then you should set the java.net.preferIPv6Addresses system property in the command line. This enables the Oracle JVM to load appropriate libraries. These libraries are loaded once and cannot be reloaded without restarting the Java process. For more information about this system property, refer to Oracle Database Java Developer's Guide.

8.2.2 Database Specifiers

Table 8-3, shows the possible database specifiers, listing which JDBC drivers support each specifier.


  • Starting Oracle Database 10g, Oracle Service IDs are not supported.

  • Starting Oracle Database 10g, Oracle no longer supports Oracle Names as a naming method.

Table 8-3 Supported Database Specifiers

Specifier Supported Drivers Example

Oracle Net connection descriptor

Thin, OCI

Thin, using an address list:


OCI, using a cluster:


Thin-style service name


Refer to "Thin-style Service Name Syntax" for details.


LDAP syntax


Refer to LDAP Syntax for details.


Bequeath connection


Empty. That is, nothing after @


TNSNames alias

Thin, OCI

Refer to "TNSNames Alias Syntax" for details.

OracleDataSource ods = new OracleDataSource();

8.2.3 Thin-style Service Name Syntax

Thin-style service names are supported only by the JDBC Thin driver. The syntax is:


For example:



The JDBC Thin driver supports only the TCP/IP protocol.

8.2.4 Support for Delay in Connection Retries

Starting from Oracle Database 12c Release 1 (, there is a new connection attribute RETRY_DELAY, which specifies the delay between connection retries in seconds. The following code snippet shows how to use this attribute:


8.2.5 TNSNames Alias Syntax

You can find the available TNSNAMES entries listed in the tnsnames.ora file on the client computer from which you are connecting. On Windows, this file is located in the ORACLE_HOME\NETWORK\ADMIN directory. On UNIX systems, you can find it in the ORACLE_HOME directory or the directory indicated in your TNS_ADMIN environment variable.

For example, if you want to connect to the database on host myhost as user HR with password hr that has a TNSNAMES entry of MyHostString, then write the following:

OracleDataSource ods = new OracleDataSource();
Connection conn = ods.getConnection();

The oracle.net.tns_admin system property must be set to the location of the tnsnames.ora file so that the JDBC Thin driver can locate the tnsnames.ora file. For example:

System.setProperty("oracle.net.tns_admin", "c:\\Temp");
String url = "jdbc:oracle:thin:@tns_entry";


When using TNSNames with the JDBC Thin driver, you must set the oracle.net.tns_admin property to the directory that contains your tnsnames.ora file.

java -Doracle.net.tns_admin=$ORACLE_HOME/network/admin

8.2.6 LDAP Syntax

An example of database specifier using the Lightweight Directory Access Protocol (LDAP) syntax is as follows:


When using SSL, change this to:



The JDBC Thin driver can use LDAP over SSL to communicate with Oracle Internet Directory if you substitute ldaps: for ldap: in the database specifier. The LDAP server must be configured to use SSL. If it is not, then the connection attempt will hang.

The JDBC Thin driver supports failover of a list of LDAP servers during the service name resolution process, without the need for a hardware load balancer. Also, client-side load balancing is supported for connecting to LDAP servers. A list of space separated LDAP URLs syntax is used to support failover and load balancing.

When a list of LDAP URLs is specified, both failover and load balancing are enabled by default. The oracle.net.ldap_loadbalance connection property can be used to disable load balancing, and the oracle.net.ldap_failover connection property can be used to disable failover.

An example, which uses failover, but with client-side load balancing disabled, is as follows:

Properties prop = new Properties();
String url = "jdbc:oracle:thin:@ldap://ldap1.example.com:3500/cn=salesdept,cn=OracleContext,dc=com/salesdb " +
"ldap://ldap2.example.com:3500/cn=salesdept,cn=OracleContext,dc=com/salesdb " +

prop.put("oracle.net.ldap_loadbalance", "OFF" );
OracleDataSource ods = new OracleDataSource();

The JDBC Thin driver supports LDAP nonanonymous bind. A set of JNDI environment properties, which contains authentication information, can be specified for a data source. If an LDAP server is configured as not to allow anonymous bind, then authentication information must be provided to connect to the LDAP server. The following example shows a simple clear-text password authentication:

String url = "jdbc:oracle:thin:@ldap://ldap.example.com:7777/sales,cn=salesdept,cn=OracleContext,dc=com";

Properties prop = new Properties();
prop.put("java.naming.security.authentication", "simple");
prop.put("java.naming.security.credentials", "mysecret");

OracleDataSource ods = new OracleDataSource();

Since JDBC passes down the three properties to JNDI, the authentication mechanism chosen by client is consistent with how these properties are interpreted by JNDI. For example, if the client specifies authentication information without explicitly specifying the java.naming.security.authentication property, then the default authentication mechanism is "simple". Please refer to relevant JDNI documentation for details.