mirror of
https://github.com/yasuhirokimura/db18
synced 2026-06-08 18:29:23 +00:00
Yasuhiro KIMURA
88 lines
2.3 KiB
C
88 lines
2.3 KiB
C
/*-
|
|
* Copyright (c) 1997, 2019 Oracle and/or its affiliates. All rights reserved.
|
|
*
|
|
* See the file EXAMPLES-LICENSE for license information.
|
|
*
|
|
*/
|
|
|
|
#include "ex_sql_utils.h"
|
|
|
|
/*
|
|
* Transactions created using BEGIN...COMMIT do not nest. For nested
|
|
* transactions, use the SAVEPOINT and RELEASE commands. The "TO SAVEPOINT
|
|
* name" clause of the ROLLBACK command is only applicable to SAVEPOINT
|
|
* transactions.
|
|
*
|
|
* This example shows how to begin/commit/rollback to a savepoint instead of
|
|
* operating whole transaction.
|
|
*/
|
|
|
|
/* Example body. */
|
|
static int
|
|
ex_sql_savepoint(db)
|
|
db_handle *db;
|
|
{
|
|
const char* disp_result;
|
|
const char* info;
|
|
disp_result = \
|
|
"SELECT rank, region, name from university WHERE rank <= 3;";
|
|
|
|
/*
|
|
* BEGIN a transaction for all following operations.
|
|
*/
|
|
echo_info("Example1. BEGIN and COMMIT a transaction explicitly");
|
|
exec_sql(db, "BEGIN");
|
|
|
|
/*
|
|
* Start to execute given sql expression. A savepoint will be started
|
|
* in the beginning of each step. We can define multi-savepoints by
|
|
* different names.
|
|
*/
|
|
info = "1. Declare savepoint sp1. Delete the rank 1 record then "
|
|
"release savepoint sp1. We can see the record has been "
|
|
"removed.";
|
|
echo_info(info);
|
|
exec_sql(db, "SAVEPOINT sp1");
|
|
exec_sql(db, disp_result); /* Display status before deleting. */
|
|
exec_sql(db, "DELETE FROM university WHERE rank = '1';");
|
|
exec_sql(db, "RELEASE sp1");
|
|
exec_sql(db, disp_result); /* Display status after deleting. */
|
|
|
|
info = "2. Declare savepoint sp2. Then remove the rank 2 record and "
|
|
"rollback. We can see the record was recovered by rollback to "
|
|
"savepoint sp2.";
|
|
echo_info(info);
|
|
exec_sql(db, "SAVEPOINT sp2");
|
|
exec_sql(db, "DELETE FROM university WHERE rank = '2';");
|
|
exec_sql(db, disp_result); /* Display status before rollback. */
|
|
exec_sql(db, "ROLLBACK TO sp2");
|
|
exec_sql(db, disp_result); /* Display status after rollback. */
|
|
|
|
/* Commit the whole transaction. */
|
|
exec_sql(db, "COMMIT TRANSACTION");
|
|
info = "3. Here is the final result. We can see only the savepoint "
|
|
"sp1 was released.";
|
|
echo_info(info);
|
|
exec_sql(db, disp_result);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
main()
|
|
{
|
|
db_handle *db;
|
|
|
|
/* Setup environment and preload data. */
|
|
db = setup("./ex_sql_savepoint.db");
|
|
load_table_from_file(db, university_sample_data, 1/* Silent */);
|
|
|
|
/* Run example. */
|
|
ex_sql_savepoint(db);
|
|
|
|
/* End. */
|
|
cleanup(db);
|
|
return 0;
|
|
}
|
|
|