Re: [Dev-C++] mysql

[Reid T. <jre...@ea...>]

Terry Orgill wrote:

> I am going to install dev-cpp and the mysql devpak on my laptop.  I 
> have had problems getting mysql to work with dev-cpp in the past.  
> What version of mysql should I download?
>
none ;)    Install PostgreSQL instead.   The install using the windows 
installer takes only a couple of minutes.

http://www.postgresql.org/ftp/binary/v8.0.3/win32/postgresql-8.0.3.zip

http://www.postgresql.org/docs/8.0/interactive/libpq.html provides 
information on how to use the libpq library ( there are also libs for 
C++ and embedded sql, etc described).

The below sample program works with Dev-Cpp(It's from the 
www.postgresql.org.docs site).  Create a new project.  Set the below as 
main.c.  Add $POSTGRESQL_HOME/$VERSION/lib/libpq.a to Project/Project 
Options/Parameters/Add Library or Object.  Add 
$POSTGRESQL_HOME/$VERSION/include to include directories.  ( I also 
attacehd the Dev-Cpp .dev and Makefile.win and main.c files)

The default connection and cursor will list info related to the default 
Postgresql db template, template1 and it's table pg_database.

The commented out conninfo and DECLARE CURSOR lines assume you have 
created a DB called test and it contains a table called test_table.  If 
you're unfamiliar with PostreSQL, the the included PGADMIN III is an 
intuitive interface.  And the www.postgresql.org.docs site has very good 
documentation.


/*
 * testlibpq.c
 *
 *              Test the C version of LIBPQ, the POSTGRES frontend library.
 */
#include <stdio.h>
#include <stdlib.h>
#include "libpq-fe.h"

static void
exit_nicely(PGconn *conn)
{
        PQfinish(conn);
        system("PAUSE");/* I added this for Dev-CPP */
        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=template1
         * and using environment variables or defaults for all other 
connection
         * parameters.
         */
        if (argc > 1)
                conninfo = argv[1];
        else
                conninfo = "hostaddr = 127.0.0.1 dbname = template1 user 
= postgres password = postgres";
                //conninfo = "hostaddr = 127.0.0.1 dbname = test user = 
postgres password = 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, "Connection to database failed: %s",
                        PQerrorMessage(conn));
                exit_nicely(conn);
        }

        /*
         * 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);
        }

        /*
         * Should PQclear PGresult whenever it is no longer needed to avoid
         * memory leaks
         */
        PQclear(res);

        /*
         * Fetch rows from pg_database, the system catalog of databases
         */
       
        res = PQexec(conn, "DECLARE myportal CURSOR FOR select * from 
pg_database");
        //res = PQexec(conn, "DECLARE myportal CURSOR FOR select * from 
test_table");
        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);
       
        system("PAUSE"); /* I added this for Dev-CPP */

        return 0;
}