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Postgres library improvements [message #22561]

Mon, 27 July 2009 10:44

Zbych
Messages: 325
Registered: July 2009

Senior Member

1. Client code page

Functions PostgreSQLConnection::ErrorMessage and PostgreSQLSession::ErrorMessage use FromSystemCharset to convert code page. Unfortunately PQerrorMessage AFAIK does not use client's system code page but the code page that is declared in lc_messages (postgresql.conf), or the code page explicit set by the client (function PQsetClientEncoding).

So I think those functions should be modified:

String PostgreSQLConnection::ErrorMessage()
{
	// no code page conversion, leave it to postgres
	return AsString(PQerrorMessage(conn));
}

String PostgreSQLSession::ErrorMessage()
{
	// no code page conversion, leave it to postgres
	return AsString(PQerrorMessage(conn));
}

And of course postgres should be informed about the code page:

bool PostgreSQLSession::Open(const char *connect)
{
	Close();
	conn = PQconnectdb(connect);
	if(PQstatus(conn) != CONNECTION_OK)
	{
		SetError(ErrorMessage(), "Opening database");
		Close();
		return false;
	}
	level = 0;
	
	// set client's code page
	int stat = PQsetClientEncoding(conn, CharsetName(GetDefaultCharset()));
	ASSERT(stat == 0);
	LOG( String("Postgresql client encoding: ") + pg_encoding_to_char( PQclientEncoding(conn) ) );
	
	return true;
}

I made some tests with UTF-8 and WIN1250, and it appears that postgres accepts code page names from ultimate Smile

2. Re-establishing connection

It would be nice to have function that reconnects to database, when connection is lost:

bool PostgreSQLSession::ReOpen()
{
	PQreset(conn);
	if(PQstatus(conn) != CONNECTION_OK)
	{
		SetError(ErrorMessage(), "Opening database");
		return false;
	}
	level = 0;
	
	return true;	
}

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