2 Ensuring Compatibility with Evolving interMedia Object Types

The Oracle interMedia ("interMedia") object types may evolve by adding new object attributes in a future release. Client-side applications that want to maintain compatibility with the current release of the interMedia object types (ORDAudio, ORDImage, ORDVideo, and ORDDoc), even after a server upgrade that includes evolved object types, are advised to do the following:

Make a call to the compatibility initialization function at the beginning of the application, if necessary (see Section 2.1).

Use the static constructor functions, init( ), in INSERT statements that are provided beginning with release 8.1.7 (see the sections on ORDAudio Constructors, ORDDoc Constructors, ORDImage Constructors, and ORDVideo Constructors). Do not use the default constructors because INSERT statements using the default constructors will fail if the interMedia object types have added new attributes.

Note:

If you do not take the preceding recommended actions, you may have to upgrade your client and perhaps even edit and recompile your application when you upgrade to a newer database release with evolved interMedia object types.

The information in this chapter is not applicable to the SQL/MM Still Image object types.

2.1 When and How to Call the Compatibility Initialization Function

Only client-side applications that statically recognize the structure of the interMedia object types need to make a call to the compatibility initialization function. Server-side stored procedures will automatically use the newly installed (potentially changed) interMedia object types after an upgrade, so you do not need to call the compatibility initialization function from server-side stored procedures.

Client-side applications that do not statically (at compile time) recognize the structure of interMedia object types do not need to call the compatibility initialization function. OCI applications that determine the structure of the interMedia object types at runtime, through the OCIDescribeAny call, do not need to call the compatibility initialization function.

Client-side applications written in OCI that have been compiled with the C structure of interMedia object types (generated by Oracle type translator) should make a call to the server-side PL/SQL function, ORDSYS.IM.compatibilityInit( ), at the beginning of the application. See the compatibilityInit( ) method description of this function in this section.

Client-side applications written in Java using Oracle interMedia Java Classes for Oracle Database release 8.1.7 or later, should call the OrdMediaUtil.imCompatibilityInit( ) function after connecting to the database.

public static void imCompatibilityInit(OracleConnection con)
    throws Exception

This Java function takes OracleConnection as an argument. The included interMedia release 8.1.7 or later Java API will ensure that your 8.1.7 or later application will work with a potential future release of interMedia with evolved object types.

There is not yet a way for client-side PL/SQL applications to maintain compatibility with the current release of the interMedia object types if the objects add new attributes in a future release.

See the compatibilityInit( ) method in this section, and Oracle interMedia Java Classes Reference for further information, and detailed descriptions and examples. This guide is on the Oracle Technology Network at

http://otn.oracle.com/