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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1997, 2015 Oracle and/or its affiliates. All rights reserved.
*
*/
#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;
}
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