srv_dynamic

Description

Read or respond to a client dynamic SQL command.

Syntax

CS_RETCODE srv_dynamic(spp, cmd, item, bufp,

                          buflen, outlenp)

SRV_PROC       *spp;
CS_INT               cmd;
CS_INT               item;
CS_VOID            *bufp
CS_INT               buflen;
CS_INT              *outlenp

Parameters

Returns

Examples

Example 1

#include        <ospublic.h>

/*

 ** Local Prototype

 */

extern CS_RETCODE                ex_srv_dynamic PROTOTYPE((

CS_VOID     *spp,

CS_INT      *optypep

));

/* 

 ** EX_SRV_DYNAMIC

**

**    Example routine to retrieve dynamic operation type from a

 **    client.

**

** Arguments:

**    spp      Thread control structure.

**    optypep  Dynamic operation type.

**

** Returns:

**

**    CS_SUCCEED   Dynamic information was retrieved 

 **                 successfully.

**    CS_FAIL      An error was detected.

 */

CS_RETCODE      ex_srv_dynamic(spp, optypep)

SRV_PROC   *spp;

CS_INT     *optypep;

{

CS_INT     outlen;

    if(srv_dynamic(spp, CS_GET, SRV_DYN_TYPE, optypep,

         sizeof(*optypep), &outlen) == CS_FAIL)

    {

        return(CS_FAIL);

    }

    return(CS_SUCCEED);

}

Usage

• The srv_dynamic routine allows an Open Server application to read a dynamic SQL command or send a response to such a command.

• Valid operation types (SRV_DYN_TYPE) include:

  CS_PREPARE – prepare a statement (CS_GET only).

  CS_DESCRIBE_INPUT – request input parameter formats for the current prepared statement (CS_GET only).

  CS_DESCRIBE_OUTPUT – request column formats for the current prepared statement (CS_GET only).

  CS_EXECUTE – execute a prepared statement (CS_GET only).

  CS_EXEC_IMMEDIATE – execute an unprepared statement, which has no parameters and does not return results (CS_GET only).

  CS_DEALLOC – deallocate a prepared statement (CS_GET only).

  CS_ACK – acknowledge a dynamic SQL command from client (CS_SET only).

• Each dynamic command received from a client triggers a SRV_DYNAMIC event. An Open Server application can then call srv_dynamic, in response to each client dynamic command, to retrieve and store the operation type, statement ID and statement, and then acknowledge the client communication, by issuing a srv_dynamic call with type set to CS_ACK.

• It is an error to call srv_dynamic in any event handler other than a SRV_DYNAMIC handler.

• CS_ACK is the only dynamic operation type that can be set (cmd set to CS_SET).

• CS_PREPARE, CS_DESCRIBE_INPUT, CS_DESCRIBE_OUTPUT, CS_EXECUTE, CS_EXEC_IMMEDIATE and CS_DEALLOC are the only dynamic operation types that can be retrieved (cmd set to CS_GET).

• Sending a full dynamic SQL response to a client requires passing the ID length, the ID, and the operation type. This requires three distinct calls to srv_dynamic. It is an error, for example, to set just the statement ID and then call srv_senddone. The only exception is if the operation type is CS_EXEC_IMMEDIATE, for which there is no associated statement ID.

• Parameter data formats and output column formats can be sent to a client, in response to a CS_PREPARE dynamic command, using srv_descfmt and srv_xferdata with a type argument of SRV_DYNDATA. Note that srv_bind is not necessary here, as the application is simply sending formats.

• An Open Server application retrieves and store the parameter data sent by a client following the CS_EXECUTE dynamic command using srv_descfmt, srv_bind, and srv_xferdata, with a type argument of SRV_DYNDATA. The application determines the number of parameters using srv_numparams.

• The application sends dynamic SQL result rows to the client, in response to a CS_EXECUTE dynamic SQL command, using srv_descfmt, srv_bind, and srv_xferdata with a type argument of SRV_ROWDATA.

• A dynamic SQL command of CS_EXEC_IMMEDIATE indicates that the client wishes to execute a statement without parameters and receive only a DONE as a result. The statement is contained in the CS_EXEC_IMMEDIATE command stream and is accessible through SRV_DYN_STMT. The statement has not been previously prepared—the statement ID length (SRV_DYN_IDLEN) will be 0—and will cease to exist once the SRV_DYNAMIC event handler has exited.

See also