Re: Calling stored function that returns a cursor from a libpq program - Mailing list pgsql-novice

char * cursorCall = "DECLARE myPortal CURSOR for select * from cars";

//BEGIN the transaction

queryResult4 = PQexec(connection, "BEGIN");

execStatus = PQresultStatus(queryResult4);  //Get the result status

char * beginTransactionErrorMessage = PQresultErrorMessage(queryResult4);

NSLog([NSString stringWithCString:beginTransactionErrorMessage]);

char* cursorCall = "select reffunc('portalName')";   //call stored function to get the cursor 

//Call the stored function that returns a CURSOR

queryResult4 = PQexec(connection, cursorCall);

execStatus = PQresultStatus(queryResult4);  //Get the result status

char * errorMessage = PQresultErrorMessage(queryResult4);

NSLog([NSString stringWithCString:errorMessage]);

if ((execStatus == PGRES_COMMAND_OK) || (execStatus == PGRES_TUPLES_OK))  {  //cursor retrieved succesfully

int numRows;  //variable to store number of rows returned in query

int numColumns;  //number of columns per row

numRows = PQntuples(queryResult4);

NSLog(@"The stored function call returned %i rows.", numRows);

numColumns =  PQnfields(queryResult4);  //get number of columns

//get the name of the returned cursor

char * cursorReturned;

cursorReturned = PQgetvalue(queryResult4, 0, 0);

NSString * fetchNextQuery = [NSString stringWithFormat:@"FETCH ALL in %s", cursorReturned];

queryResult4 = PQexec(connection,[fetchNextQuery UTF8String] );

execStatus = PQresultStatus(queryResult4);  //Get the result status

char * errorMessage2 = PQresultErrorMessage(queryResult4);

NSLog([NSString stringWithCString:errorMessage2]); ....