Full example

The following example is a complete program which creates a example_db.db SQLite database in the current directory, creates a "products" table,add a few rows to it, and then displays its contents. The example uses an SQLite database as it does not require any server setup and can thus be run as-is. That example can be found in the samples/SimpleExample/example.c.

To compile it, run:

cc -o example example.c `pkg-config --cflags --libs libgda-3.0`
      

The code is:

#include <libgda/libgda.h>

GdaConnection *open_connection (GdaClient *client);
void display_products_contents (GdaConnection *cnc);
void create_table (GdaConnection *cnc);
void run_sql_non_select (GdaConnection *cnc, const gchar *sql);

int
main (int argc, char *argv[])
{
        gda_init ("SimpleExample", "1.0", argc, argv);

        GdaClient *client;
        GdaConnection *cnc;

        /* Create a GdaClient object which is the central object which manages all connections */
        client = gda_client_new ();

	/* open connections */
	cnc = open_connection (client);
	create_table (cnc);
	display_products_contents (cnc);
        gda_connection_close (cnc);

        return 0;
}

/*
 * Open a connection to the example.db file
 */
GdaConnection *
open_connection (GdaClient *client)
{
        GdaConnection *cnc;
        GError *error = NULL;
        cnc = gda_client_open_connection_from_string (client, "SQLite", 
						      "DB_DIR=.;DB_NAME=example_db", 
						      NULL, NULL,
						      GDA_CONNECTION_OPTIONS_DONT_SHARE,
						      &error);
        if (!cnc) {
                g_print ("Could not open connection to SQLite database in "
			 "example_db.db file: %s\n",
                         error && error->message ? error->message : "No detail");
                exit (1);
        }
        return cnc;
}

/*
 * Create a "products" table
 */
void
create_table (GdaConnection *cnc)
{
	run_sql_non_select (cnc, "DROP table IF EXISTS products");
        run_sql_non_select (cnc, "CREATE table products "
			    "(ref string not null primary key, "
                            "name string not null, price real)");
	run_sql_non_select (cnc, "INSERT INTO products VALUES ('p1', 'chair', 2.0)");
	run_sql_non_select (cnc, "INSERT INTO products VALUES ('p2', 'table', 5.0)");
	run_sql_non_select (cnc, "INSERT INTO products VALUES ('p3', 'glass', 1.1)");
}


/* 
 * display the contents of the 'products' table 
 */
void
display_products_contents (GdaConnection *cnc)
{
	GdaDataModel *data_model;
	GdaCommand *command;
	gchar *sql = "SELECT ref, name, price FROM products";
	GError *error = NULL;

	command = gda_command_new (sql, GDA_COMMAND_TYPE_SQL, 
				   GDA_COMMAND_OPTION_STOP_ON_ERRORS);
	data_model = gda_connection_execute_select_command (cnc, command, NULL, &error);
	gda_command_free (command);
        if (!data_model) 
                g_error ("Could not get the contents of the 'products' table: %s\n",
                         error && error->message ? error->message : "No detail");
	gda_data_model_dump (data_model, stdout);
	g_object_unref (data_model);
}

/*
 * run a non SELECT command and stops if an error occurs
 */
void
run_sql_non_select (GdaConnection *cnc, const gchar *sql)
{
        GdaCommand *command;
        GError *error = NULL;
        gint nrows;

        command = gda_command_new (sql, GDA_COMMAND_TYPE_SQL, 0);
        nrows = gda_connection_execute_non_select_command (cnc, command, NULL, &error);
        gda_command_free (command);
        if (nrows == -1)
                g_error ("NON SELECT error: %s\n", 
			 error && error->message ? error->message : "no detail");
}