mirror of
https://github.com/yasuhirokimura/db18
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Yasuhiro KIMURA
95 lines
2.0 KiB
C
95 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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* This example demonstrates how to execute queries.
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* Example 1. Single Select.
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* Example 2. Using 'WHERE' and 'ORDER BY'.
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* Example 3. Using 'GROUP BY'.
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* Example 4. Subquery.
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* Example 5. SQL function.
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*/
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/* Example body. */
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static int
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ex_sql_query(db)
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db_handle *db;
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{
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const char* sql;
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/*
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* Example 1: Single Select.
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* - Select rank and name from table university.
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*/
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echo_info("1. Single Select");
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sql = "\tSELECT rank, name from university;";
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exec_sql(db, sql);
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/*
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* Example 2: Use 'WHERE' and 'ORDER BY' to arrange results
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* - Select rank, name and country from table university where
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* region is Europe. ORDER by country.
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*/
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echo_info("2. Using 'WHERE' and 'ORDER BY'");
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sql = "\tSELECT rank, country, name \n"
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"\tFROM university \n"
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"\tWHERE region = 'Europe' \n"
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"\tORDER BY country;";
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exec_sql(db, sql);
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/*
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* Example 3: Using 'Group by'.
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*/
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echo_info("3. Group by");
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sql = "\tSELECT region, count(*) from university \n"
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"\tGROUP BY region \n"
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"\tORDER BY region";
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exec_sql(db, sql);
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/*
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* Example 4 Subquery
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* - Select rank, name and country from table university where
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* country's fullname is 'USA'.
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*/
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echo_info("4. Subquery");
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sql = "\tSELECT rank, country, name from university \n"
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"\tWHERE country = (SELECT abbr from country \n"
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"\t\t\tWHERE country = 'USA');";
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exec_sql(db, sql);
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/*
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* Example 5: SQL functions
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* - Output current system date.
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*/
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echo_info("5. SQL functions: Echo current date");
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sql = "\tSELECT date('now');";
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exec_sql(db, sql);
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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_query.db");
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load_table_from_file(db, university_sample_data, 1/* Silent */);
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load_table_from_file(db, country_sample_data, 1/* Silent */);
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/* Run example. */
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ex_sql_query(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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