1 OCI: Introduction and Upgrading

Advantages of OCI

OCI provides significant advantages over other methods of accessing an Oracle Database:

• More fine-grained control over all aspects of application design

• High degree of control over program execution

• Use of familiar third-generation language programming techniques and application development tools, such as browsers and debuggers

• Connection pooling, session pooling, and statement caching that enable building of scalable applications

• Support of dynamic SQL

• Availability on the broadest range of operating systems of all the Oracle programmatic interfaces

• Dynamic binding and defining using callbacks

• Description functionality to expose layers of server metadata

• Asynchronous event notification for registered client applications

• Enhanced array data manipulation language (DML) capability for array inserts, updates, and deletes

• Ability to associate commit requests with executes to reduce round-trips

• Optimization of queries using transparent prefetch buffers to reduce round-trips

• Thread safety, which eliminates the need for mutual exclusive locks (mutexes) on OCI handles

Building an OCI Application

You compile and link an OCI program in the same way that you compile and link a non-database application. There is no need for a separate preprocessing or precompilation step.

Oracle Database supports most popular third-party compilers. The details of linking an OCI program vary from system to system. On some operating systems, it may be necessary to include other libraries, in addition to the OCI library, to properly link your OCI programs. See your Oracle Database system-specific documentation and the installation guide for more information about compiling and linking an OCI application for your operating system.

Parts of OCI

OCI has the following functionality:

• APIs to design a scalable, multithreaded application that can support large numbers of users securely

• SQL access functions, for managing database access, processing SQL statements, and manipulating objects retrieved from an Oracle database

• Data type mapping and manipulation functions, for manipulating data attributes of Oracle types

• Data loading functions, for loading data directly into the database without using SQL statements

• External procedure functions, for writing C callbacks from PL/SQL

Procedural and Nonprocedural Elements

OCI enables you to develop scalable, multithreaded applications in a multitier architecture that combines the nonprocedural data access power of structured query language (SQL) with the procedural capabilities of C and C++.

• In a nonprocedural language program, the set of data to be operated on is specified, but what operations are to be performed, or how the operations are to be conducted, is not specified. The nonprocedural nature of SQL makes it an easy language to learn and to use to perform database transactions. It is also the standard language used to access and manipulate data in modern relational and object-relational database systems.

• In a procedural language program, the execution of most statements depends on previous or subsequent statements and on control structures, such as loops or conditional branches, that are not available in SQL. The procedural nature of these languages makes them more complex than SQL, but it also makes them more flexible and powerful.

The combination of both nonprocedural and procedural language elements in an OCI program provides easy access to an Oracle database in a structured programming environment.

OCI supports all SQL data definition, data manipulation, query, and transaction control facilities that are available through an Oracle database. For example, an OCI program can run a query against an Oracle database. The query can require the program to supply data to the database using input (bind) variables, as follows:

SELECT name FROM employees WHERE empno = :empnumber;

In the preceding SQL statement, :empnumber is a placeholder for a value that is to be supplied by the application.

You can also take advantage of PL/SQL, Oracle's procedural extension to SQL. The applications you develop can be more powerful and flexible than applications written in SQL alone. OCI also provides facilities for accessing and manipulating objects in a database.

Object Support

OCI has facilities for working with object types and objects. An object type is a user-defined data structure representing an abstraction of a real-world entity. For example, the database might contain a definition of a person object. That object might have attributes—first_name, last_name, and age—to represent a person's identifying characteristics.

The object type definition serves as the basis for creating objects that represent instances of the object type by using the object type as a structural definition, you could create a person object with the attribute values 'John', 'Bonivento', and '30'. Object types may also contain methods—programmatic functions that represent the behavior of that object type.

OCI includes functions that extend the capabilities of OCI to handle objects in an Oracle Database. These capabilities include:

• Executing SQL statements that manipulate object data and schema information

• Passing of object references and instances as input variables in SQL statements

• Declaring object references and instances as variables to receive the output of SQL statements

• Fetching object references and instances from a database

• Describing the properties of SQL statements that return object instances and references

• Describing PL/SQL procedures or functions with object parameters or results

• Extension of commit and rollback calls to synchronize object and relational functionality

Additional OCI calls are provided to support manipulation of objects after they have been accessed by SQL statements. For a more detailed description, see "Encapsulated Interfaces".

SQL Statements

One of the main tasks of an OCI application is to process SQL statements. Different types of SQL statements require different processing steps in your program. It is important to take this into account when coding your OCI application. Oracle Database recognizes several types of SQL statements:

• Data Definition Language (DDL)

• Control Statements

  • Transaction Control

  • Session Control

  • System Control

• Data Manipulation Language (DML)

• Queries

  Note:

  Queries are often classified as DML statements, but OCI applications process queries differently, so they are considered separately here.

• PL/SQL

• Embedded SQL

  See Also:

  Chapter 4, "Using SQL Statements in OCI"

CREATE TABLE employees
    (name       VARCHAR2(20),
     ssn        VARCHAR2(12),
     empno      NUMBER(6),
     mgr        NUMBER(6),
     salary     NUMBER(6));

GRANT UPDATE, INSERT, DELETE ON employees TO donna;
REVOKE UPDATE ON employees FROM jamie;

CREATE TYPE person_t AS OBJECT (
    name     VARCHAR2(30),
    ssn      VARCHAR2(12),
    address  VARCHAR2(50));

CREATE TABLE person_tab OF person_t;

INSERT INTO person_tab
    VALUES (person_t('Steve May','987-65-4320','146 Winfield Street'));

SELECT dname FROM dept
     WHERE deptno = 42;

SELECT name 
    FROM employees
    WHERE empno = :empnumber;

BEGIN
    SELECT ename, sal, comm INTO :emp_name, :salary, :commission
    FROM emp
    WHERE empno = :emp_number;
END;

SELECT customer, address
FROM customers
WHERE bus_type = 'SOFTWARE'
AND sales_volume = :sales;

Encapsulated Interfaces

All the data structures that are used by OCI calls are encapsulated in the form of opaque interfaces that are called handles. A handle is an opaque pointer to a storage area allocated by the OCI library that stores context information, connection information, error information, or bind information about a SQL or PL/SQL statement. A client allocates certain types of handles, populates one or more of those handles through well-defined interfaces, and sends requests to the server using those handles. In turn, applications can access the specific information contained in a handle by using accessor functions.

The OCI library manages a hierarchy of handles. Encapsulating the OCI interfaces with these handles has several benefits to the application developer, including:

• Reduction of server-side state information that must be retained, thereby reducing server-side memory usage

• Improvement of productivity by eliminating the need for global variables, making error reporting easier, and providing consistency in the way OCI variables are accessed and used

• Allows changes to be made to the underlying structure without affecting applications

Simplified User Authentication and Password Management

OCI provides application developers with simplified user authentication and password management in several ways:

• OCI enables a single OCI application to authenticate and maintain multiple users.

• OCI enables the application to update a user's password, which is particularly helpful if an expired password message is returned by an authentication attempt.

OCI supports two types of login sessions:

• A simplified login function for sessions by which a single user connects to the database using a login name and password

• A mechanism by which a single OCI application authenticates and maintains multiple sessions by separating the login session (the session created when a user logs in to an Oracle database) from the user sessions (all other sessions created by a user)

Extensions to Improve Application Performance and Scalability

OCI provides several feature extensions to improve application performance and scalability. Application performance has been improved by reducing the number of client to server round-trips required, and scalability improvements have been made by reducing the amount of state information that must be retained on the server side. Some of these features include:

• Increased client-side processing, and reduced server-side requirements on queries

• Implicit prefetching of SELECT statement result sets to eliminate the describe round-trip, reduce round-trips, and reduce memory usage

• Elimination of open and closed cursor round-trips

• Improved support for multithreaded environments

• Session multiplexing over connections

• Consistent support for a variety of configurations, including standard two-tier client/server configurations, server-to-server transaction coordination, and three-tier TP-monitor configurations

• Consistent support for local and global transactions, including support for the XA interface's TM_JOIN operation

• Improved scalability by providing the ability to concentrate connections, processes, and sessions across users on connections and by eliminating the need for separate sessions to be created for each branch of a global transaction

• Allowing applications to authenticate multiple users and allow transactions to be started on their behalf

OCI Object Support

OCI provides a comprehensive application programming interface for programmers seeking to use Oracle Database object capabilities. These features can be divided into the following major categories:

• Client-Side Object Cache

• Associative and Navigational Interfaces to access and manipulate objects

• OCI Runtime Environment for Objects

• Type Management: Mapping and Manipulation Functions to access information about object types and control data attributes of Oracle types

• Object Type Translator (OTT) utility, for mapping internal Oracle Database schema information to client-side language bind variables

OCI Support for Oracle Streams Advanced Queuing

OCI provides an interface to Oracle Streams Advanced Queuing (Streams AQ) feature. Streams AQ provides message queuing as an integrated part of Oracle Database. Streams AQ provides this functionality by integrating the queuing system with the database, thereby creating a message-enabled database. By providing an integrated solution, Streams AQ frees you to devote your efforts to your specific business logic rather than having to construct a messaging infrastructure.

XA Library Support

OCI supports the Oracle XA library. The xa.h header file is in the same location as all the other OCI header files. For Linux or UNIX, the path is $ORACLE_HOME/rdbms/public. Users of the demo_rdbms.mk file on Linux or UNIX are not affected because this make file includes the $ORACLE_HOME/rdbms/public directory.

For Windows, the path is ORACLE_BASE\ORACLE_HOME\oci\include.

Version Compatibility of Statically Linked and Dynamically Linked Applications

Here are the rules for relinking for a new release.

• Statically linked OCI applications:

  Statically linked OCI applications must be relinked for both major and minor releases, because the statically linked Oracle Database client-side library code may be incompatible with the error messages in the upgraded Oracle home. For example, if an error message was updated with additional parameters then it is no longer compatible with the statically linked code.

• Dynamically linked OCI applications:

  Dynamically linked OCI applications from Oracle Database 10g and later releases need not be relinked. That is, the Oracle Database client-side dynamic library is upwardly compatible with the previous version of the library. Oracle Universal Installer creates a symbolic link for the previous version of the library that resolves to the current version. Therefore, an application that is dynamically linked with the previous version of the Oracle Database client-side dynamic library does not need to be relinked to operate with the current version of the Oracle Database client-side library.

  Note:

  If the application is linked with a runtime library search path (such as -rpath on Linux), then the application may still run with the version of Oracle Database client-side library it is linked with. To run with the current version of Oracle Database client-side library, it must be relinked.

  See Also:

  • Oracle Database Upgrade Guide for information about compatibility and upgrading

  • The server versions supported currently are found on My Oracle Support in note 207303.1. See the website at

    https://support.oracle.com/

Simplified Upgrading of Existing OCI Release 7 Applications

OCI has been significantly improved with many features since OCI release 7. Applications written to work with OCI release 7 have a smooth migration path to the current OCI release because of the interoperability of OCI release 7 clients with the current release of the Oracle Database, and of clients of the current release with Oracle Database release 7.

Specifically:

• Applications that use the OCI release 7.3 API work unchanged against the current release of Oracle Database. They do need to be linked with the current client library.

• OCI release 7 and the OCI calls of this release can be mixed in the same application and in the same transaction provided they are not mixed within the same statement execution.

As a result, when migrating an existing OCI version 7 application you have the following two alternatives:

• Upgrade to the current OCI client but do not modify the application: If you choose to upgrade from an Oracle release 7 OCI client to the current release OCI client, you need only link the new version of the OCI library and need not recompile your application. The relinked Oracle Database release 7 OCI applications work unchanged against a current Oracle Database.

• Upgrade to the current OCI client and modify the application: To use the performance and scalability benefits provided by the current OCI, however, you must modify your existing applications to use the current OCI programming paradigm, relink them with the current OCI library, and run them against the current release of the Oracle database.

If you want to use any of the object capabilities of the current Oracle Database release, you must upgrade your client to the current release of OCI.

Obsolete OCI Routines

Release 8.0 of the OCI introduced an entirely new set of functions that were not available in release 7.3. Oracle Database continues to support these release 7.3 functions. Many of the earlier 7.x calls are available, but Oracle strongly recommends that new applications use the new calls to improve performance and provide increased functionality.

Table 1-1 lists the 7.x OCI calls with their later equivalents. For more information about the OCI calls, see the function descriptions in this guide. For more information about the 7.x calls, see Programmer's Guide to the Oracle Call Interface, Release 7.3. These 7.x calls are obsolete, meaning that OCI has replaced them with newer calls. Although the obsolete calls are now supported, they may not be supported in all future versions of OCI.

OCI Routines Not Supported

Some OCI routines that were available in previous versions of OCI are not supported in the current release. They are listed in Table 1-2.

Compatibility Between Different Releases of OCI and Servers

This section addresses compatibility between different releases of OCI and Oracle Database.

Existing 7.x applications with no new post-release 7.x calls have to be relinked with the current client-side library.

The application cannot use the object features of Oracle8i or later, and cannot get any of the performance or scalability benefits provided by those OCI releases.

Upgrading OCI

Programmers who want to incorporate post-release 7.x functionality into existing OCI applications have two options:

• Completely rewrite the application to use only current OCI calls (recommended).

• Incorporate current OCI post-release 7.x calls into the application, while still using 7.x calls for some operations.

This manual should provide the information necessary to rewrite an existing application to use only current OCI calls.

Benefits of Instant Client

Why use Instant Client?

• Installation involves copying a small number of files.

• The Oracle Database client-side number of required files and the total disk storage are significantly reduced.

• There is no loss of functionality or performance for applications deployed in Instant Client mode.

• It is simple for independent software vendors to package applications.

OCI Instant Client Installation Process

The Instant Client libraries can be installed by either choosing the Instant Client option from Oracle Universal Installer or by downloading and installing the Instant Client libraries from the OCI page (see the bottom of OCI page for the Instant Client link) on the Oracle Technology Network website:

http://www.oracle.com/technology/tech/oci/instantclient/index.html

To Download and Install the Instant Client Libraries from the Oracle Technology Network Website

1. Download and install the Instant Client shared libraries to an empty directory, such as instantclient_11_2, for Oracle Database release 11.2. Choose the Basic package.

2. Set the operating system shared library path environment variable to the directory from Step 1. For example, on Linux or UNIX, set LD_LIBRARY_PATH to instantclient_11_2. On Windows, set PATH to the instantclient_11_2 directory.

3. If necessary, use NLS_LANG to reset the client system's language, territory, and character set.

After completing the preceding steps you are ready to run the OCI application.

The OCI application operates in Instant Client mode when the OCI shared libraries are accessible through the operating system Library Path variable. In this mode, there is no dependency on the Oracle home and none of the other code and data files provided in the Oracle home are needed by OCI (except for the tnsnames.ora file described later).

To Install the Instant Client from the Oracle Universal Installer

1. Invoke the Oracle Universal Installer and select the Instant Client option.

2. Install the Instant Client shared libraries to an empty directory, such as instantclient_11_2, for release 11.2.

3. Set the LD_LIBRARY_PATH to the instant client directory to operate in instant client mode.

4. If necessary, use NLS_LANG to reset the client system's language, territory, and character set.

If you did a complete client installation (by choosing the Admin option in Oracle Universal Installer), the Instant Client shared libraries are also installed. The locations of the Instant Client shared libraries in a full client installation are:

On Linux or UNIX:

libociei.so library is in $ORACLE_HOME/instantclient

libclntsh.so.11.1 and libnnz11.so are in $ORACLE_HOME/lib

On Windows:

oraociei11.dll library is in ORACLE_HOME\instantclient

oci.dll, ociw32.dll, and orannzsbb11.dll are in ORACLE_HOME\bin

To enable running the OCI application in Instant Client mode, copy the preceding libraries to a different directory and set the operating system shared library path to locate this directory.

To enable other capabilities such as OCCI and JDBC OCI, you must copy a few additional files. To enable OCCI, you must install the OCCI Library (libocci.so.11.1 on Linux or UNIX and oraocci11.dll on Windows) in the Instant Client directory. For the JDBC OCI driver, in addition to the three OCI shared libraries, you must also download OCI JDBC Library (for example libocijdbc11.so on Linux or UNIX and ocijdbc11.dll on Windows). Place all libraries in the Instant Client directory.

When to Use Instant Client

Instant Client is a deployment feature and should be used for running production applications. In general, all OCI functionality is available to an application being run in the Instant Client mode, except that the Instant Client mode is for client-side operation only. Therefore, server-side external procedures cannot operate in the Instant Client mode.

For development you can also use the Instant Client SDK.

Patching Instant Client Shared Libraries on Linux or UNIX

Because Instant Client is a deployment feature, the number and size of files (client footprint) required to run an OCI application has been reduced. Hence, all files needed to patch Instant Client shared libraries are not available in an Instant Client deployment. A colplete client installation based on Oracle home is needed to patch the Instant Client shared libraries. Use the opatch utility to patch the Instant Client shared libraries.

After you apply the patch in an Oracle home environment, copy the files listed in Table 1-3 to the instant client directory, as described in "OCI Instant Client Installation Process".

Instead of copying individual files, you can generate Instant Client zip and RPM files for OCI and OCCI, JDBC, and SQL*Plus as described in "Regeneration of Data Shared Library and Zip and RPM Files". Then, you can copy the zip and RPM files to the target system and unzip them as described in "OCI Instant Client Installation Process".

The opatch utility stores the patching information of the ORACLE_HOME installation in libclntsh.so . This information can be retrieved by the following command:

genezi -v

If the Instant Client deployment system does not have the genezi utility, you can copy it from the ORACLE_HOME/bin directory.

Regeneration of Data Shared Library and Zip and RPM Files

The process to regenerate the data shared library and the zip and RPM files has changed for release 11.2 and later. Separate targets are added to create the data shared libraries, zip, and RPM files either individually or all at once. In previous releases, one target, ilibociei, was provided to build the data shared libraries, zip, and RPM files. Now ilibociei builds only the zip and RPM files. Regeneration of data shared libraries requires both a compiler and linker, which may not be available on all installations. Therefore, separate targets have been added to regenerate the data shared libraries.

cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk igenlibociei

mkdir -p $ORACLE_HOME/rdbms/install/instantclient/light
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk igenlibociicus

mkdir -p $ORACLE_HOME/rdbms/install/instantclient/light
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk igenliboci

cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_basic_zip

cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_basiclite_zip

cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_jdbc_zip

cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_odbc_zip

cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_sqlplus_zip

cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_tools_zip

cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ilibociei

Database Connection Strings for OCI Instant Client

OCI Instant Client can make remote database connections in all the ways that ordinary SQL clients can. However, because Instant Client does not have the Oracle home environment and directory structure, some database naming methods require additional configuration steps.

All Oracle Net naming methods that do not require use of ORACLE_HOME or TNS_ADMIN (to locate configuration files such as tnsnames.ora or sqlnet.ora) work in the Instant Client mode. In particular, the connect_identifier in the OCIServerAttach() call can be specified in the following formats:

• A SQL Connect URL string of the form:

  [//]host[:port][/service name]
  

  For example:

  //dlsun242:5521/bjava21
  

• As an Oracle Net connect descriptor. For example:

  "(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp) (HOST=dlsun242) (PORT=5521))
  (CONNECT_DATA=(SERVICE_NAME=bjava21)))"
  

• A Connection Name that is resolved through Directory Naming where the site is configured for LDAP server discovery.

For naming methods such as tnsnames and directory naming to work, the TNS_ADMIN environment variable must be set.

If the TNS_ADMIN environment variable is not set, and TNSNAMES entries such as inst1, and so on, are used, then the ORACLE_HOME variable must be set, and the configuration files are expected to be in the $ORACLE_HOME/network/admin directory.

Note that the ORACLE_HOME variable in this case is only used for locating Oracle Net configuration files, and no other component of Client Code Library (OCI, NLS, and so on) uses the value of ORACLE_HOME.

If a NULL string, "", is used as the connection string in the OCIServerAttach() call, then the TWO_TASK environment variable can be set to the connect_identifier. On a Windows operating system, the LOCAL environment variable is used instead of TWO_TASK.

Similarly, for OCI command-line applications such as SQL*Plus, the TWO_TASK (or LOCAL on Windows) environment variable can be set to the connect_identifier. Its value can be anything that would have gone to the right of the '@' on a typical connect string.

LISTENER = (ADDRESS_LIST=
 (ADDRESS=(PROTOCOL=tcp)(HOST=server6)(PORT=1573))
)
 
SID_LIST_LISTENER = (SID_LIST= 
 (SID_DESC=(SID_NAME=rdbms3)(GLOBAL_DBNAME=rdbms3.server6.us.alchemy.com)
(ORACLE_HOME=/home/dba/rdbms3/oracle))
)

"(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=server6)(PORT=1573))(CONNECT_DATA=
(SERVICE_NAME=rdbms3.server6.us.alchemy.com)))"

"//server6:1573/rdbms3.server6.us.alchemy.com"

setenv TWO_TASK "(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=server6)(PORT=1573))
(CONNECT_DATA=(SERVICE_NAME=rdbms3.server6.us.alchemy.com)))"

setenv TWO_TASK //server6:1573/rdbms3.server6.us.alchemy.com

sqlplus user

conn_str = (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=server6)(PORT=1573))(CONNECT_DATA=
(SERVICE_NAME=rdbms3.server6.us.alchemy.com)))

setenv TNS_ADMIN /home/webuser/instantclient

setenv ORACLE_HOME /network/server6/home/dba/oracle

setenv TWO_TASK conn_str

Environment Variables for OCI Instant Client

The ORACLE_HOME environment variable no longer determines the location of NLS, CORE, and error message files. An OCI-only application should not require ORACLE_HOME to be set. However, if it is set, it does not affect OCI. OCI always obtains its data from the Data Shared Library. If the Data Shared Library is not available, only then is ORACLE_HOME used and a full client installation is assumed. Though ORACLE_HOME is not required to be set, if it is set, then it must be set to a valid operating system path name that identifies a directory.

If Dynamic User callback libraries are to be loaded, then as this guide specifies, the callback package must reside in ORACLE_HOME/lib (ORACLE_HOME\bin on Windows). Set ORACLE_HOME in this case.

Environment variables ORA_NLS10 and ORA_NLS_PROFILE33 are ignored in the Instant Client mode.

In the Instant Client mode, if the ORA_TZFILE variable is not set, then the larger, default, timezlrg_n.dat file from the Data Shared Library is used. If the smaller timezone_n.dat file is to be used from the Data Shared Library, then set the ORA_TZFILE environment variable to the name of the file without any absolute or relative path names.

On Linux or UNIX:

setenv ORA_TZFILE timezone_n.dat

On Windows:

set ORA_TZFILE=timezone_n.dat

In these examples, n is the time zone data file version number.

To determine the versions of small and large timezone files that are packaged in the Instant Client Data Shared Library, enter the following command to run the genezi utility:

genezi -v

If OCI is not operating in the Instant Client mode (because the Data Shared Library is not available), then ORA_TZFILE variable, if set, names a complete path name as it does in previous Oracle Database releases.

If TNSNAMES entries are used, then, as mentioned earlier, TNS_ADMIN directory must contain the TNSNAMES configuration files. If TNS_ADMIN is not set, then the ORACLE_HOME/network/admin directory must contain Oracle Net Services configuration files.

Instant Client Light (English)

The Instant Client Light (English) version of Instant Client further reduces the disk space requirements of the client installation. The size of the library has been reduced by removing error message files for languages other than English and leaving only a few supported character set definitions out of around 250.

This Instant Client Light version is geared toward applications that use either US7ASCII, WE8DEC, WE8ISO8859P1, WE8MSWIN1252, or a Unicode character set. There is no restriction on the LANGUAGE and the TERRITORY fields of the NLS_LANG setting, so the Instant Client Light operates with any language and territory settings. Because only English error messages are provided with the Instant Client Light, error messages generated on the client side, such as Net connection errors, are always reported in English, even if NLS_LANG is set to a language other than AMERICAN. Error messages generated by the database side, such as syntax errors in SQL statements, are in the selected language provided the appropriate translated message files are installed in the Oracle home of the database instance.

SDK for Instant Client

The SDK can be downloaded from the Instant Client link on the OCI URL (see the bottom of OCI page for the Instant Client link) on the Oracle Technology Network website:

http://www.oracle.com/technology/tech/oci/instantclient/

• The Instant Client SDK package has both C and C++ header files and a makefile for developing OCI and OCCI applications while in an Instant Client environment. Developed applications can be deployed in any client environment.

• The SDK contains C and C++ demonstration programs.

• On Windows, libraries required to link the OCI or OCCI applications are also included. Make.bat is provided to build the demos.

• On UNIX or Linux, the makefile demo.mk is provided to build the demos. The instantclient_11_2 directory must be on the LD_LIBRARY_PATH before linking the application. The OCI and OCCI programs require the presence of libclntsh.so and libocci.so symbolic links in the instantclient_11_2 directory. demo.mk creates these before the link step. These symbolic links can also be created in a shell:

  cd instantclient_11_2
  ln -s libclntsh.so.11.1 libclntsh.so
  ln -s libocci.so.11.1 libocci.so
  

• The SDK also contains the Object Type Translator (OTT) utility and its classes to generate the application header files.