/* * Program type: API Interface * * Description: * This program performs a multi-database transaction * with a two-phase commit. A 'currency' field is updated * in database 1 for table country, and corresponding * 'from_currency' or 'to_currency' fields are updated in * database 2 for table cross_rate. The transaction is * committed only if all instances of the string are * changed successfully in both databases. * The contents of this file are subject to the Interbase Public * License Version 1.0 (the "License"); you may not use this file * except in compliance with the License. You may obtain a copy * of the License at http://www.Inprise.com/IPL.html * * Software distributed under the License is distributed on an * "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express * or implied. See the License for the specific language governing * rights and limitations under the License. * * The Original Code was created by Inprise Corporation * and its predecessors. Portions created by Inprise Corporation are * Copyright (C) Inprise Corporation. * * All Rights Reserved. * Contributor(s): ______________________________________. */ #include <stdlib.h> #include <string.h> #include <ibase.h> #include <stdio.h> #include "example.h" #define BUFLEN 512 #define CURRENLEN 10 char *sel_str1 = "SELECT currency FROM country WHERE country = 'Canada'"; int main (int argc, char** argv) { char *country = "Canada"; /* passed as a parameter */ char *new_name = "CdnDollar"; /* passed as a parameter */ char orig_name[CURRENLEN + 1]; char buf[BUFLEN + 1]; isc_db_handle db1 = NULL, /* handle for database 1 */ db2 = NULL; /* handle for database 2 */ isc_tr_handle trans1 = NULL; /* transaction handle */ ISC_STATUS_ARRAY status; XSQLDA * sel_sqlda; isc_stmt_handle stmt = NULL; long stat1, stat2, stat3; char empdb[128], empdb2[128]; if (argc > 1) strcpy(empdb, argv[1]); else strcpy(empdb, "employee.fdb"); if (argc > 2) strcpy(empdb2, argv[2]); else strcpy(empdb2, "employe2.fdb"); /* Open database 1. */ printf("Attaching to database %s\n", empdb); if (isc_attach_database(status, 0, empdb, &db1, 0, NULL)) { ERREXIT(status, 1) } /* Open database 2. */ printf ("Attaching to database %s\n", empdb2); if (isc_attach_database(status, 0, empdb2, &db2, 0, NULL)) { ERREXIT(status, 1) } /* Start a two-database transaction. */ if (isc_start_transaction(status, &trans1, 2, &db1, 0, NULL, &db2, 0, NULL)) { ERREXIT(status, 1) } /* * Get the string, which is to be globally changed. */ sprintf(buf, "SELECT currency FROM country WHERE country = '%s'", country); sel_sqlda = (XSQLDA *) malloc(XSQLDA_LENGTH(1)); sel_sqlda->sqln = 1; sel_sqlda->version = 1; if (isc_dsql_allocate_statement(status, &db1, &stmt)) { ERREXIT(status, 1) } if (isc_dsql_prepare(status, &trans1, &stmt, 0, sel_str1, 1, sel_sqlda)) { ERREXIT(status, 1) } sel_sqlda->sqlvar[0].sqldata = orig_name; sel_sqlda->sqlvar[0].sqltype = SQL_TEXT; sel_sqlda->sqlvar[0].sqllen = CURRENLEN; if (isc_dsql_execute(status, &trans1, &stmt, 1, NULL)) { ERREXIT(status, 1) } if (isc_dsql_fetch(status, &stmt, 1, sel_sqlda)) { ERREXIT(status, 1) } orig_name[CURRENLEN] = '\0'; printf("Modifying currency string: %s\n", orig_name); /* * Change the string in database 1. */ sprintf(buf, "UPDATE country SET currency = '%s' WHERE country = 'Canada'", new_name); stat1 = 0L; if (isc_dsql_execute_immediate(status, &db1, &trans1, 0, buf, 1, NULL)) { isc_print_status(status); stat1 = isc_sqlcode(status); } /* * Change all corresponding occurences of the string in database 2. */ sprintf(buf, "UPDATE cross_rate SET from_currency = '%s' WHERE \ from_currency = '%s'", new_name, orig_name); stat2 = 0L; if (isc_dsql_execute_immediate(status, &db2, &trans1, 0, buf, 1, NULL)) { isc_print_status(status); stat2 = isc_sqlcode(status); } sprintf(buf, "UPDATE cross_rate SET to_currency = '%s' WHERE \ to_currency = '%s'", new_name, orig_name); stat3 = 0L; if (isc_dsql_execute_immediate(status, &db2, &trans1, 0, buf, 1, NULL)) { isc_print_status(status); stat3 = isc_sqlcode(status); } if (isc_dsql_free_statement(status, &stmt, DSQL_close)) isc_print_status(status); /* * If all statements executed successfully, commit the transaction. * Otherwise, undo all work. */ if (!stat1 && !stat2 && !stat3) { if (isc_commit_transaction (status, &trans1)) isc_print_status(status); printf("Changes committed.\n"); } else { printf("update1: %d\n", stat1); printf("update2: %d\n", stat2); printf("update3: %d\n", stat3); if (isc_rollback_transaction(status, &trans1)) isc_print_status(status); printf("Changes undone.\n"); } /* Close database 1. */ if (isc_detach_database(status, &db1)) isc_print_status(status); /* Close database 2. */ if (isc_detach_database(status, &db2)) isc_print_status(status); free(sel_sqlda); return 0; }