1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
|
/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1997, 2013 Oracle and/or its affiliates. All rights reserved.
*
*/
#include "ex_sql_utils.h"
/*
* Transactions define boundaries around a group of SQL commands such that
* they either all successfully execute together or not at all.
*
* SQLite automatically runs each command in its own transaction, and if the
* command does not fail, its changes are automatically committed. This mode
* of operation (implicit transactions) is referred to as autocommit mode.
*
* This example shows how to use explicit transaction to appoint transaction
* scopes. It can reduces transaction number(compare with autocommit mode)
* and improve system efficiency.
*
* Example1: Commit a transaction explicitly.
* Example2: Rollback a transaction explicitly.
*
* Transactions created using BEGIN...COMMIT do not nest. For nested
* transactions, use the SAVEPOINT and RELEASE commands.
*
*/
/* Example body. */
static int
ex_sql_transaction(db)
db_handle *db;
{
const char* disp_result;
disp_result = "SELECT rank, region, name from university;";
/*
* Example1: BEGIN and COMMIT a transaction explicitly.
*/
echo_info("Example1. BEGIN and COMMIT a transaction explicitly");
exec_sql(db, "BEGIN TRANSACTION");
exec_sql(db, "DELETE FROM university WHERE region = 'Asia';");
exec_sql(db, "COMMIT TRANSACTION");
exec_sql(db, disp_result);
/*
* Example2: Rollback a transaction explicitly.
*/
echo_info("Example2. Rollback a transaction explicitly");
exec_sql(db, "BEGIN TRANSACTION");
exec_sql(db, "DELETE FROM university WHERE region = 'Europe';");
exec_sql(db, disp_result);
exec_sql(db, "ROLLBACK TRANSACTION");
exec_sql(db, disp_result);
return 0;
}
int
main()
{
db_handle *db;
/* Setup environment and preload data. */
db = setup("./ex_sql_transaction.db");
load_table_from_file(db, university_sample_data, 1/* Silent */);
/* Run example. */
ex_sql_transaction(db);
/* End. */
cleanup(db);
return 0;
}
|
