Initial data commit

Task/Parameterized-SQL-statement/C/parameterized-sql-statement.c

@@ -0,0 +1,114 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sqlite3.h>
+
+static const char* db_file = ":memory:"; // Create an in-memory database.
+
+void check_error(int result_code, sqlite3 *db);
+int select_callback(void* data, int column_count, char** columns, char** column_names);
+
+int main(void) {
+    sqlite3 *db;
+    int result_code;
+    char *sql;
+    char *insert_statements[4];
+    sqlite3_stmt *compiled_statement;
+    int i;
+
+    // Open the database.
+    result_code = sqlite3_open(db_file, &db);
+    check_error(result_code, db);
+
+    // Create the players table in the database.
+    sql = "create table players("
+          "id integer primary key asc, "
+          "name text, "
+          "score real, "
+          "active integer, " // Store the bool value as integer (see https://sqlite.org/datatype3.html chapter 2.1).
+          "jerseyNum integer);";
+    result_code = sqlite3_exec(db, sql, NULL, NULL, NULL);
+    check_error(result_code, db);
+
+    // Insert some values into the players table.
+    insert_statements[0] = "insert into players (name, score, active, jerseyNum) "
+                                        "values ('Roethlisberger, Ben', 94.1, 1, 7);";
+    insert_statements[1] = "insert into players (name, score, active, jerseyNum) "
+                                        "values ('Smith, Alex', 85.3, 1, 11);";
+    insert_statements[2] = "insert into players (name, score, active, jerseyNum) "
+                                        "values ('Manning, Payton', 96.5, 0, 18);";
+    insert_statements[3] = "insert into players (name, score, active, jerseyNum) "
+                                        "values ('Doe, John', 15, 0, 99);";
+
+    for (i=0; i<4; i++) {
+        result_code = sqlite3_exec(db, insert_statements[i], NULL, NULL, NULL);
+        check_error(result_code, db);
+    }
+
+    // Display the contents of the players table.
+    printf("Before update:\n");
+    sql = "select * from players;";
+    result_code = sqlite3_exec(db, sql, select_callback, NULL, NULL);
+    check_error(result_code, db);
+
+    // Prepare the parametrized SQL statement to update player #99.
+    sql = "update players set name=?, score=?, active=? where jerseyNum=?;";
+    result_code = sqlite3_prepare_v2(db, sql, -1, &compiled_statement, NULL);
+    check_error(result_code, db);
+
+    // Bind the values to the parameters (see https://sqlite.org/c3ref/bind_blob.html).
+    result_code = sqlite3_bind_text(compiled_statement, 1, "Smith, Steve", -1, NULL);
+    check_error(result_code, db);
+    result_code = sqlite3_bind_double(compiled_statement, 2, 42);
+    check_error(result_code, db);
+    result_code = sqlite3_bind_int(compiled_statement, 3, 1);
+    check_error(result_code, db);
+    result_code = sqlite3_bind_int(compiled_statement, 4, 99);
+    check_error(result_code, db);
+
+    // Evaluate the prepared SQL statement.
+    result_code = sqlite3_step(compiled_statement);
+    if (result_code != SQLITE_DONE) {
+        printf("Error #%d: %s\n", result_code, sqlite3_errmsg(db));
+        sqlite3_close(db);
+        return result_code;
+    }
+
+    // Destroy the prepared statement object.
+    result_code = sqlite3_finalize(compiled_statement);
+    check_error(result_code, db);
+
+    // Display the contents of the players table.
+    printf("After update:\n");
+    sql = "select * from players;";
+    result_code = sqlite3_exec(db, sql, select_callback, NULL, NULL);
+    check_error(result_code, db);
+
+    // Close the database connection.
+    sqlite3_close(db);
+
+    return EXIT_SUCCESS;
+}
+
+/*
+  Checks the result code from an SQLite operation.
+  If it contains an error code then this function prints the error message,
+  closes the database and exits.
+*/
+void check_error(int result_code, sqlite3 *db) {
+    if (result_code != SQLITE_OK) {
+        printf("Error #%d: %s\n", result_code, sqlite3_errmsg(db));
+        sqlite3_close(db);
+        exit(result_code);
+    }
+}
+
+/* This callback function prints the results of the select statement. */
+int select_callback(void* data, int column_count, char** columns, char** column_names) {
+    int i;
+
+    for (i=0; i<column_count; i++) {
+        printf(columns[i]);
+        if (i < column_count-1) printf(" | ");
+    }
+    printf("\n");
+}