16 OCI Relational Functions

This chapter begins to describe the OCI relational functions for C. It includes information about calling OCI functions in your application, along with detailed descriptions of each function call.

Introduction to the Relational Functions

This chapter and Chapter 17 describe the OCI relational function calls and cover the functions in the basic OCI.

Conventions for OCI Functions

For each function, the following information is listed:

Purpose

A brief description of the action performed by the function.

Syntax

The function declaration.

Parameters

A description of each of the function's parameters. This includes the parameter's mode. The mode of a parameter has three possible values, as described in Table 16-1.

Table 16-1 Mode of a Parameter

Mode	Description
IN	A parameter that passes data to the OCI
OUT	A parameter that receives data from the OCI on this call
IN/OUT	A parameter that passes data on the call and receives data on the return from this or a subsequent call

Comments

More detailed information about the function (if available). This may include restrictions on the use of the function, or other information that might be useful when using the function in an application.

Returns

This optional section describes the possible values that can be returned. It can be found either before or after the Comments section.

Example

A complete or partial code example demonstrating the use of the function call being described. Not all function descriptions include an example.

Related Functions

A list of related function calls.

Calling OCI Functions

Unlike earlier versions of OCI, in and after release 8, you cannot pass -1 for the string length parameter of a NULL-terminated string. When you pass string lengths as parameters, do not include the NULL terminator byte in the length. The OCI does not expect strings to be NULL-terminated.

Buffer lengths that are OCI parameters are in bytes, with the following exceptions:

The amount parameters in some LOB calls are in characters
When UTF-16 encoding of text is used in function parameters, the length is in character points

Server Round-Trips for LOB Functions

For a table showing the number of server round-trips required for individual OCI LOB functions, see Appendix C.