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<title>DDL example: GNOME Data Access 5 manual</title>
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<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="ddl_example"></a>DDL example</h2></div></div></div>
<p>
The following example illustrates (in a very simple way) how to use the
<a class="link" href="GdaServerOperation.html" title="GdaServerOperation">GdaServerOperation</a> object to perform a CREATE TABLE query.
For more information about how <span class="application">Libgda</span> handles DDL queries, see <a class="link" href="ch21.html#DDLIntro" title="General words about DDL queries">the DDL introduction</a>.
The following code simply executes the equivalent of "CREATE TABLE products (id int PRIMARY KEY, product_name string NOT NULL);"
in a generic way, where the "id" field is the primary key and should be auto incremented (the SQL is generally
specific to each DBMS for that last part).
</p>
<p>
For SQLite, the actual executed SQL statement is:
</p>
<pre class="programlisting">
CREATE TABLE products (id integer PRIMARY KEY AUTOINCREMENT, product_name varchar(50) NOT NULL);
</pre>
<p>
whereas for MySQL, the code would be:
</p>
<pre class="programlisting">
CREATE TABLE products (id integer AUTO_INCREMENT PRIMARY KEY, product_name varchar(50) NOT NULL) ENGINE=InnoDB;
</pre>
<p>
</p>
<p>
The code is:
</p>
<pre class="programlisting">
void
create_table (GdaConnection *cnc)
{
GError *error = NULL;
GdaServerProvider *provider;
GdaServerOperation *op;
gint i;
/* create a new GdaServerOperation object */
provider = gda_connection_get_provider (cnc);
op = gda_server_provider_create_operation (provider, cnc, GDA_SERVER_OPERATION_CREATE_TABLE, NULL, &error);
if (!op) {
g_print ("CREATE TABLE operation is not supported by the provider: %s\n",
error && error->message ? error->message : "No detail");
exit (1);
}
/* Set parameter's values */
/* table name */
if (!gda_server_operation_set_value_at (op, "products", &error, "/TABLE_DEF_P/TABLE_NAME")) goto on_set_error;
if (!gda_server_operation_set_value_at (op, "InnoDB", &error, "/TABLE_OPTIONS_P/TABLE_ENGINE")) goto on_set_error;
/* "id' field */
i = 0;
if (!gda_server_operation_set_value_at (op, "id", &error, "/FIELDS_A/@COLUMN_NAME/%d", i)) goto on_set_error;
if (!gda_server_operation_set_value_at (op, "integer", &error, "/FIELDS_A/@COLUMN_TYPE/%d", i)) goto on_set_error;
if (!gda_server_operation_set_value_at (op, "TRUE", &error, "/FIELDS_A/@COLUMN_AUTOINC/%d", i)) goto on_set_error;
if (!gda_server_operation_set_value_at (op, "TRUE", &error, "/FIELDS_A/@COLUMN_PKEY/%d", i)) goto on_set_error;
/* 'product_name' field */
i++;
if (!gda_server_operation_set_value_at (op, "product_name", &error, "/FIELDS_A/@COLUMN_NAME/%d", i)) goto on_set_error;
if (!gda_server_operation_set_value_at (op, "varchar", &error, "/FIELDS_A/@COLUMN_TYPE/%d", i)) goto on_set_error;
if (!gda_server_operation_set_value_at (op, "50", &error, "/FIELDS_A/@COLUMN_SIZE/%d", i)) goto on_set_error;
if (!gda_server_operation_set_value_at (op, "TRUE", &error, "/FIELDS_A/@COLUMN_NNUL/%d", i)) goto on_set_error;
/* Actually execute the operation */
if (! gda_server_provider_perform_operation (provider, cnc, op, &error)) {
g_print ("Error executing the operation: %s\n",
error && error->message ? error->message : "No detail");
exit (1);
}
g_object_unref (op);
return;
on_set_error:
g_print ("Error setting value in GdaSererOperation: %s\n",
error && error->message ? error->message : "No detail");
exit (1);
}
</pre>
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