execute.c

关系型数据库 Postgresql 6.5.2

/* Module:          execute.c
 *
 * Description:     This module contains routines related to 
 *                  preparing and executing an SQL statement.
 *
 * Classes:         n/a
 *
 * API functions:   SQLPrepare, SQLExecute, SQLExecDirect, SQLTransact,
 *                  SQLCancel, SQLNativeSql, SQLParamData, SQLPutData
 *
 * Comments:        See "notice.txt" for copyright and license information.
 *
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "psqlodbc.h"
#include <stdio.h>
#include <string.h>

#ifndef WIN32
#include "iodbc.h"
#include "isqlext.h"
#else
#include <windows.h>
#include <sqlext.h>
#endif

#include "connection.h"
#include "statement.h"
#include "qresult.h"
#include "convert.h"
#include "bind.h"
#include "lobj.h"

extern GLOBAL_VALUES globals;


//      Perform a Prepare on the SQL statement
RETCODE SQL_API SQLPrepare(HSTMT     hstmt,
                           UCHAR FAR *szSqlStr,
                           SDWORD    cbSqlStr)
{
static char *func = "SQLPrepare";
StatementClass *self = (StatementClass *) hstmt;

	mylog( "%s: entering...\n", func);

	if ( ! self) {
		SC_log_error(func, "", NULL);
		return SQL_INVALID_HANDLE;
	}
    
	/*	According to the ODBC specs it is valid to call SQLPrepare mulitple times.
		In that case, the bound SQL statement is replaced by the new one 
	*/

	switch(self->status) {
	case STMT_PREMATURE:
		mylog("**** SQLPrepare: STMT_PREMATURE, recycle\n");
		SC_recycle_statement(self); /* recycle the statement, but do not remove parameter bindings */
		break;

	case STMT_FINISHED:
		mylog("**** SQLPrepare: STMT_FINISHED, recycle\n");
		SC_recycle_statement(self); /* recycle the statement, but do not remove parameter bindings */
		break;

	case STMT_ALLOCATED:
		mylog("**** SQLPrepare: STMT_ALLOCATED, copy\n");
		self->status = STMT_READY;
		break;

	case STMT_READY:
		mylog("**** SQLPrepare: STMT_READY, change SQL\n");
		break;

	case STMT_EXECUTING:
		mylog("**** SQLPrepare: STMT_EXECUTING, error!\n");

		self->errornumber = STMT_SEQUENCE_ERROR;
		self->errormsg = "SQLPrepare(): The handle does not point to a statement that is ready to be executed";
		SC_log_error(func, "", self);

		return SQL_ERROR;

	default:
		self->errornumber = STMT_INTERNAL_ERROR;
		self->errormsg = "An Internal Error has occured -- Unknown statement status.";
		SC_log_error(func, "", self);
		return SQL_ERROR;
	}

	if (self->statement)
		free(self->statement);

	self->statement = make_string(szSqlStr, cbSqlStr, NULL);
	if ( ! self->statement) {
		self->errornumber = STMT_NO_MEMORY_ERROR;
		self->errormsg = "No memory available to store statement";
		SC_log_error(func, "", self);
		return SQL_ERROR;
	}

	self->prepare = TRUE;
	self->statement_type = statement_type(self->statement);

	//	Check if connection is readonly (only selects are allowed)
	if ( CC_is_readonly(self->hdbc) && STMT_UPDATE(self)) {
		self->errornumber = STMT_EXEC_ERROR;
		self->errormsg = "Connection is readonly, only select statements are allowed.";
		SC_log_error(func, "", self);
		return SQL_ERROR;
	}

	return SQL_SUCCESS;


}

//      -       -       -       -       -       -       -       -       -

//      Performs the equivalent of SQLPrepare, followed by SQLExecute.

RETCODE SQL_API SQLExecDirect(
        HSTMT     hstmt,
        UCHAR FAR *szSqlStr,
        SDWORD    cbSqlStr)
{
StatementClass *stmt = (StatementClass *) hstmt;
RETCODE result;
static char *func = "SQLExecDirect";

	mylog( "%s: entering...\n", func);
    
	if ( ! stmt) {
		SC_log_error(func, "", NULL);
		return SQL_INVALID_HANDLE;
	}

	if (stmt->statement)
		free(stmt->statement);

	// keep a copy of the un-parametrized statement, in case
	// they try to execute this statement again
	stmt->statement = make_string(szSqlStr, cbSqlStr, NULL);
	if ( ! stmt->statement) {
		stmt->errornumber = STMT_NO_MEMORY_ERROR;
		stmt->errormsg = "No memory available to store statement";
		SC_log_error(func, "", stmt);
		return SQL_ERROR;
	}

	mylog("**** %s: hstmt=%u, statement='%s'\n", func, hstmt, stmt->statement);

	stmt->prepare = FALSE;
	stmt->statement_type = statement_type(stmt->statement);

	//	Check if connection is readonly (only selects are allowed)
	if ( CC_is_readonly(stmt->hdbc) && STMT_UPDATE(stmt)) {
		stmt->errornumber = STMT_EXEC_ERROR;
		stmt->errormsg = "Connection is readonly, only select statements are allowed.";
		SC_log_error(func, "", stmt);
		return SQL_ERROR;
	}
	
	mylog("%s: calling SQLExecute...\n", func);

	result = SQLExecute(hstmt);

	mylog("%s: returned %hd from SQLExecute\n", func, result);
	return result;
}

//      Execute a prepared SQL statement
RETCODE SQL_API SQLExecute(
        HSTMT   hstmt)
{
static char *func="SQLExecute";
StatementClass *stmt = (StatementClass *) hstmt;
ConnectionClass *conn;
int i, retval;


	mylog("%s: entering...\n", func);

	if ( ! stmt) {
		SC_log_error(func, "", NULL);
		mylog("%s: NULL statement so return SQL_INVALID_HANDLE\n", func);
		return SQL_INVALID_HANDLE;
	}

	/*  If the statement is premature, it means we already executed
		it from an SQLPrepare/SQLDescribeCol type of scenario.  So
		just return success.
	*/
	if ( stmt->prepare && stmt->status == STMT_PREMATURE) {
		stmt->status = STMT_FINISHED;       
		if (stmt->errormsg == NULL) {
			mylog("%s: premature statement but return SQL_SUCCESS\n", func);
			return SQL_SUCCESS;
		}
		else {
			SC_log_error(func, "", stmt);
			mylog("%s: premature statement so return SQL_ERROR\n", func);
			return SQL_ERROR;
		}
	}  

	mylog("%s: clear errors...\n", func);

	SC_clear_error(stmt);

	conn = SC_get_conn(stmt);
	if (conn->status == CONN_EXECUTING) {
		stmt->errormsg = "Connection is already in use.";
		stmt->errornumber = STMT_SEQUENCE_ERROR;
		SC_log_error(func, "", stmt);
		mylog("%s: problem with connection\n", func);
		return SQL_ERROR;
	}

	if ( ! stmt->statement) {
		stmt->errornumber = STMT_NO_STMTSTRING;
		stmt->errormsg = "This handle does not have a SQL statement stored in it";
		SC_log_error(func, "", stmt);
		mylog("%s: problem with handle\n", func);
		return SQL_ERROR;
	}

	/*	If SQLExecute is being called again, recycle the statement.
		Note this should have been done by the application in a call
		to SQLFreeStmt(SQL_CLOSE) or SQLCancel.
	*/
	if (stmt->status == STMT_FINISHED) {
		mylog("%s: recycling statement (should have been done by app)...\n", func);
		SC_recycle_statement(stmt);
	}

	/*	Check if the statement is in the correct state */
	if ((stmt->prepare && stmt->status != STMT_READY) || 
		(stmt->status != STMT_ALLOCATED && stmt->status != STMT_READY)) {
		
		stmt->errornumber = STMT_STATUS_ERROR;
		stmt->errormsg = "The handle does not point to a statement that is ready to be executed";
		SC_log_error(func, "", stmt);
		mylog("%s: problem with statement\n", func);
		return SQL_ERROR;
	}


	/*	The bound parameters could have possibly changed since the last execute
		of this statement?  Therefore check for params and re-copy.
	*/
	stmt->data_at_exec = -1;
	for (i = 0; i < stmt->parameters_allocated; i++) {
		/*	Check for data at execution parameters */
		if ( stmt->parameters[i].data_at_exec == TRUE) {
			if (stmt->data_at_exec < 0)
				stmt->data_at_exec = 1;
			else
				stmt->data_at_exec++;
		}
	}
	//	If there are some data at execution parameters, return need data
	//	SQLParamData and SQLPutData will be used to send params and execute the statement.
	if (stmt->data_at_exec > 0)
		return SQL_NEED_DATA;


	mylog("%s: copying statement params: trans_status=%d, len=%d, stmt='%s'\n", func, conn->transact_status, strlen(stmt->statement), stmt->statement);

	//	Create the statement with parameters substituted.
	retval = copy_statement_with_parameters(stmt);
	if( retval != SQL_SUCCESS)
		/* error msg passed from above */
		return retval;

	mylog("   stmt_with_params = '%s'\n", stmt->stmt_with_params);


	return SC_execute(stmt);

}




//      -       -       -       -       -       -       -       -       -
RETCODE SQL_API SQLTransact(
        HENV    henv,
        HDBC    hdbc,
        UWORD   fType)
{
static char *func = "SQLTransact";
extern ConnectionClass *conns[];
ConnectionClass *conn;
QResultClass *res;
char ok, *stmt_string;
int lf;

	mylog("entering %s: hdbc=%u, henv=%u\n", func, hdbc, henv);

	if (hdbc == SQL_NULL_HDBC && henv == SQL_NULL_HENV) {
		CC_log_error(func, "", NULL);
		return SQL_INVALID_HANDLE;
	}

	/* If hdbc is null and henv is valid,
	it means transact all connections on that henv.  
	*/
	if (hdbc == SQL_NULL_HDBC && henv != SQL_NULL_HENV) {
		for (lf=0; lf <MAX_CONNECTIONS; lf++) {
			conn = conns[lf];

			if (conn && conn->henv == henv)
				if ( SQLTransact(henv, (HDBC) conn, fType) != SQL_SUCCESS)
					return SQL_ERROR;

		}
		return SQL_SUCCESS;       
	}

	conn = (ConnectionClass *) hdbc;

	if (fType == SQL_COMMIT) {
		stmt_string = "COMMIT";

	} else if (fType == SQL_ROLLBACK) {
		stmt_string = "ROLLBACK";

	} else {
		conn->errornumber = CONN_INVALID_ARGUMENT_NO;
		conn->errormsg ="SQLTransact can only be called with SQL_COMMIT or SQL_ROLLBACK as parameter";
		CC_log_error(func, "", conn);
		return SQL_ERROR;
	}    

	/*	If manual commit and in transaction, then proceed. */
	if ( ! CC_is_in_autocommit(conn) &&  CC_is_in_trans(conn)) {

		mylog("SQLTransact: sending on conn %d '%s'\n", conn, stmt_string);

		res = CC_send_query(conn, stmt_string, NULL);
		CC_set_no_trans(conn);

		if ( ! res) {
			//	error msg will be in the connection
			CC_log_error(func, "", conn);
			return SQL_ERROR;
		}

		ok = QR_command_successful(res);   
		QR_Destructor(res);

		if (!ok) {
			CC_log_error(func, "", conn);
			return SQL_ERROR;
		}
	}    
	return SQL_SUCCESS;
}