95 lines
2.3 KiB
C
95 lines
2.3 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <libpq-fe.h>
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void do_exit(PGconn *conn) {
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PQfinish(conn);
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exit(1);
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}
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int main(int argc, char *argv[]) {
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/*declaration*/
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const char *conninfo;
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const int LEN = 10;
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const char *paramValues[1];
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printf("main() Started...\n");
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if (argc != 3) {
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fprintf(stderr, "Usage: %s <row id> <connection info>\n", argv[0]);
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exit(1);
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}
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printf("main() argv[1]: %s\n", argv[1]);
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int rowId;
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/*store command line argument in int variable*/
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/*validate user input*/
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/*omit SQL injection*/
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/*stream:argv*/
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int ret = sscanf(argv[1], "%d", &rowId);
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/*valid user input:1 successfully filled item*/
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if (ret != 1) {
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fprintf(stderr, "The argument must be an integer\n");
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exit(1);
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}
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if (rowId < 0) {
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fprintf(stderr, "Error passing a negative rowId\n");
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exit(1);
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}
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printf("main() LEN: %d\n", LEN);
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char str[LEN];
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printf("main() str.length: %ld\n", sizeof(str));
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snprintf(str, LEN, "%d", rowId);
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printf("main() str: %s\n", str);
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paramValues[0] = str;
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/*read command line*/
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printf("main() argv[2]: %s\n", argv[2]);
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conninfo = argv[2];
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/*connect to database*/
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PGconn *conn = PQconnectdb(conninfo);
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if (PQstatus(conn) == CONNECTION_BAD) {
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fprintf(stderr, "Connection to database failed: %s\n",
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PQerrorMessage(conn));
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PQfinish(conn);
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exit(1);
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}else if(PQstatus(conn)==CONNECTION_OK){
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printf("main() connected to database\n");
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}else{
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printf("main() connection status NOT known\n");
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}
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/*SQL statement*/
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char *stm = "SELECT * FROM cars_cleanup WHERE Id=$1";
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/*create prepared statement*/
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/*conn:connection*/
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/*stm:statement*/
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/*1:number of passed parameters*/
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/*NULL: server figures out parameter type*/
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/*paramValues:pointer of an array of strings containing parameters*/
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/*NULL:relevant for binary parameters*/
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/*NULL:relevant for binary parameters*/
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/*0:obtain result in text format*/
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PGresult *res = PQexecParams(conn, stm, 1, NULL, paramValues,
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NULL, NULL, 0);
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if (PQresultStatus(res) != PGRES_TUPLES_OK) {
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printf("No data retrieved\n");
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PQclear(res);
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do_exit(conn);
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}
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printf("%s %s %s\n", PQgetvalue(res, 0, 0),
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PQgetvalue(res, 0, 1), PQgetvalue(res, 0, 2));
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PQclear(res);
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PQfinish(conn);
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return 0;
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}
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