mirror of
https://github.com/yasuhirokimura/db18
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Yasuhiro KIMURA
77 lines
2.0 KiB
C
77 lines
2.0 KiB
C
/*-
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* Copyright (c) 1997, 2019 Oracle and/or its affiliates. All rights reserved.
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*
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* See the file EXAMPLES-LICENSE for license information.
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*
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*/
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#include "ex_sql_utils.h"
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/*
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* Transactions define boundaries around a group of SQL commands such that
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* they either all successfully execute together or not at all.
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*
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* SQLite automatically runs each command in its own transaction, and if the
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* command does not fail, its changes are automatically committed. This mode
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* of operation (implicit transactions) is referred to as autocommit mode.
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*
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* This example shows how to use explicit transaction to appoint transaction
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* scopes. It can reduces transaction number(compare with autocommit mode)
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* and improve system efficiency.
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*
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* Example1: Commit a transaction explicitly.
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* Example2: Rollback a transaction explicitly.
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*
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* Transactions created using BEGIN...COMMIT do not nest. For nested
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* transactions, use the SAVEPOINT and RELEASE commands.
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*
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*/
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/* Example body. */
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static int
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ex_sql_transaction(db)
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db_handle *db;
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{
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const char* disp_result;
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disp_result = "SELECT rank, region, name from university;";
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/*
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* Example1: BEGIN and COMMIT a transaction explicitly.
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*/
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echo_info("Example1. BEGIN and COMMIT a transaction explicitly");
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exec_sql(db, "BEGIN TRANSACTION");
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exec_sql(db, "DELETE FROM university WHERE region = 'Asia';");
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exec_sql(db, "COMMIT TRANSACTION");
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exec_sql(db, disp_result);
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/*
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* Example2: Rollback a transaction explicitly.
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*/
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echo_info("Example2. Rollback a transaction explicitly");
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exec_sql(db, "BEGIN TRANSACTION");
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exec_sql(db, "DELETE FROM university WHERE region = 'Europe';");
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exec_sql(db, disp_result);
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exec_sql(db, "ROLLBACK TRANSACTION");
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exec_sql(db, disp_result);
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return 0;
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}
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int
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main()
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{
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db_handle *db;
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/* Setup environment and preload data. */
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db = setup("./ex_sql_transaction.db");
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load_table_from_file(db, university_sample_data, 1/* Silent */);
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/* Run example. */
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ex_sql_transaction(db);
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/* End. */
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cleanup(db);
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return 0;
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}
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