15
OCI Relational Functions

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

Introduction to the Relational Functions

This chapter describes the OCI relational function calls. This chapter and the next, cover the functions in the basic OCI.

See Also:

For information about return codes and error handling, refer to the section "Error Handling"

Function Syntax

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 below.

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.

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 the 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, except:

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, refer to Appendix C, "OCI Function Server Round-trips".

Connect, Authorize, and Initialize Functions

This section describes the OCI connect, authorize, and initialize functions.

Table 15-1 Connect, Authorize, and Initialize Functions

Function	Purpose
OCIConnectionPoolCreate()	Initializes the connection pool.
OCIConnectionPoolDestroy()	Destroys the connection pool.
OCIEnvCreate()	Creates and initializes an OCI environment
OCIEnvInit()	Initialize an environment handle
OCIInitialize()	Initialize OCI process environment
OCILogon()	Simplified single-session logon
OCILogon2()	Create a logon session in connection pooling mode.
OCIServerAttach()	Attach to a server; initialize server context handle
OCIServerDetach()	Detach from a server; uninitialize server context handle
OCISessionBegin()	Authenticate a user
OCISessionEnd()	Terminate a user session
OCITerminate()	Detaches from a shared memory subsystem.

15 OCI Relational Functions