DBFREW - Call-Level Interface Version 2

DBFREW

DBFREW is the rewind function of DBCHCL.

DBFREW sends a reset- pointer request to the Teradata Database.

How It Works

DBFREW performs the following functions:

If the session is active, awaits completion

If Keep response is set to 'N' at the time of submitting the request whose response is to be rewound, then CLI will return 310 error.

If a Failure or Error parcel is received in response to the request whose response is to be rewound, then CLI will return 310 error.

If there is a first fetch buffer, positions to the beginning.

If Keep Response is set and there is no first Fetch buffer, sends a Continue Request message containing a Rewind parcel and return to caller

Requesting a Rewind

The sequence of operations to request a rewind is:

If the reset request is successful on the client, the Teradata Database resets its parcel pointer to the first parcel in the response and sends the first portion of the response to the client.

Note: Rewind does not include fetch (DBFFET). The application program must submit a Fetch separately.

If rewinding may be required, sets Keep Response to Y when the request is submitted.

If Keep Response is set to N, the response may have been discarded by the time a rewind is required. If rewinding is required, sets Keep Response to ‘Y’ or ‘P’ when the request is submitted.

Values Read and Used, But Not Stored

The values of Wait Across Crash, Tell About Crash, Return Time, and Wait For Response are read and used, but not stored.

Interface

Function:	DBFREW - Rewind
Purpose:	Reposition to beginning of response
Parms:

DBCAREA Parameter

The following fields in the DBCAREA may be read or written to by DBCHCL’s DBFREW, depending on the application program’s environment.

Input Arguments

Change Options

Function

Input Request Id

Input Session Id

Request Buffer Length

Response Buffer Length

Return Time

Tell About Crash

Token

Wait Across Crash

Wait For Response

Output Arguments

Current Response Buffer Length

Message Length

Message Text

MTDP Sent

Return Code