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Copy from stdin (PostgreSQL) support in U++ SQL [message #53427]

Thu, 02 April 2020 20:41

shutalker
Messages: 15
Registered: November 2017
Location: Moscow

Promising Member

Hi all!
Is it possible to execute

COPY table_name FROM STDIN

via Sql interface?
I'm trying to do something like this

PostgreSQLSession pgSession;
	
if (!pgSession.Open("dbname=postgres user=postgres")) {
	RLOG("failed to setup postgresql session");
	return;
}
	
Sql sql(pgSession);

// Is there a way to setup any IO stream for data transfer?
	
if (!sql.Execute("COPY my_test_table FROM STDIN")) {
	RLOG("failed to copy data from client: " << sql.GetLastError());
	return;
}

But I don't know how to transfer data I want to import into database.

UPD: I've made a temporary dirty hack that works. This hack requires psql client to be installed

        ...
        LocalProcess psqlClient;
	String psqlCopyCmd = Format("\\COPY \"%s\" FROM STDIN", tableName);

	if (!psqlClient.Start("psql", {config["database"]["init"], "-c", psqlCopyCmd}))
	    throw String("failed to run psql client in child process");

        ...

        String copyLine;
        ...
        psqlClient.Write(copyLine);
        ...

	psqlClient.CloseWrite();
	String exitMessage;
	psqlClient.Finish(exitMessage);

	if (psqlClient.GetExitCode() != 0)
	    throw Format("failed to import 3d-data into database: %s", exitMessage);
        ...

[Updated on: Fri, 03 April 2020 14:35]

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