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Diffstat (limited to 'src/test/examples/testlibpq.c')
-rw-r--r-- | src/test/examples/testlibpq.c | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/src/test/examples/testlibpq.c b/src/test/examples/testlibpq.c new file mode 100644 index 0000000..0372781 --- /dev/null +++ b/src/test/examples/testlibpq.c @@ -0,0 +1,131 @@ +/* + * src/test/examples/testlibpq.c + * + * + * testlibpq.c + * + * Test the C version of libpq, the PostgreSQL frontend library. + */ +#include <stdio.h> +#include <stdlib.h> +#include "libpq-fe.h" + +static void +exit_nicely(PGconn *conn) +{ + PQfinish(conn); + exit(1); +} + +int +main(int argc, char **argv) +{ + const char *conninfo; + PGconn *conn; + PGresult *res; + int nFields; + int i, + j; + + /* + * If the user supplies a parameter on the command line, use it as the + * conninfo string; otherwise default to setting dbname=postgres and using + * environment variables or defaults for all other connection parameters. + */ + if (argc > 1) + conninfo = argv[1]; + else + conninfo = "dbname = postgres"; + + /* Make a connection to the database */ + conn = PQconnectdb(conninfo); + + /* Check to see that the backend connection was successfully made */ + if (PQstatus(conn) != CONNECTION_OK) + { + fprintf(stderr, "%s", PQerrorMessage(conn)); + exit_nicely(conn); + } + + /* Set always-secure search path, so malicious users can't take control. */ + res = PQexec(conn, + "SELECT pg_catalog.set_config('search_path', '', false)"); + if (PQresultStatus(res) != PGRES_TUPLES_OK) + { + fprintf(stderr, "SET failed: %s", PQerrorMessage(conn)); + PQclear(res); + exit_nicely(conn); + } + + /* + * Should PQclear PGresult whenever it is no longer needed to avoid memory + * leaks + */ + PQclear(res); + + /* + * Our test case here involves using a cursor, for which we must be inside + * a transaction block. We could do the whole thing with a single + * PQexec() of "select * from pg_database", but that's too trivial to make + * a good example. + */ + + /* Start a transaction block */ + res = PQexec(conn, "BEGIN"); + if (PQresultStatus(res) != PGRES_COMMAND_OK) + { + fprintf(stderr, "BEGIN command failed: %s", PQerrorMessage(conn)); + PQclear(res); + exit_nicely(conn); + } + PQclear(res); + + /* + * Fetch rows from pg_database, the system catalog of databases + */ + res = PQexec(conn, "DECLARE myportal CURSOR FOR select * from pg_database"); + if (PQresultStatus(res) != PGRES_COMMAND_OK) + { + fprintf(stderr, "DECLARE CURSOR failed: %s", PQerrorMessage(conn)); + PQclear(res); + exit_nicely(conn); + } + PQclear(res); + + res = PQexec(conn, "FETCH ALL in myportal"); + if (PQresultStatus(res) != PGRES_TUPLES_OK) + { + fprintf(stderr, "FETCH ALL failed: %s", PQerrorMessage(conn)); + PQclear(res); + exit_nicely(conn); + } + + /* first, print out the attribute names */ + nFields = PQnfields(res); + for (i = 0; i < nFields; i++) + printf("%-15s", PQfname(res, i)); + printf("\n\n"); + + /* next, print out the rows */ + for (i = 0; i < PQntuples(res); i++) + { + for (j = 0; j < nFields; j++) + printf("%-15s", PQgetvalue(res, i, j)); + printf("\n"); + } + + PQclear(res); + + /* close the portal ... we don't bother to check for errors ... */ + res = PQexec(conn, "CLOSE myportal"); + PQclear(res); + + /* end the transaction */ + res = PQexec(conn, "END"); + PQclear(res); + + /* close the connection to the database and cleanup */ + PQfinish(conn); + + return 0; +} |