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Program testpg;
{ Demo program to test pascal connection with postgres database }
{ Translated from the testlibpq example program of PostGreSQL }
Uses postgres,strings;
Procedure exit_nicely(Conn : PPGconn);
begin
PQfinish(conn);
halt(1);
end;
Var
pghost,pgport,pgoptions,pgtty,dbname : Pchar;
nFields,i,j : longint;
conn : PPGConn;
res : PPGresult;
begin
pghost := NiL; { host name of the backend server }
pgport := NiL; { port of the backend server }
pgoptions := NiL; { special options to start up the backend server }
pgtty := NiL; { debugging tty for the backend server }
dbName := 'template1';
{ make a connection to the database }
conn := PQsetdb(pghost, pgport, pgoptions, pgtty, dbName);
{ check to see that the backend connection was successfully made }
if (PQstatus(conn) = CONNECTION_BAD) then
begin
Writeln (stderr, 'Connection to database ',dbname,' failed.');
Writeln (stderr, PQerrorMessage(conn));
exit_nicely(conn);
end;
{ start a transaction block }
res := PQexec(conn, 'BEGIN');
if (PQresultStatus(res) <> PGRES_COMMAND_OK) then
begin
Writeln (stderr, 'BEGIN command failed');
PQclear(res);
exit_nicely(conn);
end;
{
* should PQclear PGresult whenever it is no longer needed to avoid
* memory leaks
}
PQclear(res);
{
* fetch instances from the pg_database, the system catalog of
* databases
}
res := PQexec(conn, 'DECLARE myportal CURSOR FOR select * from pg_database');
if (PQresultStatus(res) <> PGRES_COMMAND_OK) then
begin
Writeln (stderr, 'DECLARE CURSOR command failed');
PQclear(res);
exit_nicely(conn);
end;
PQclear(res);
res := PQexec(conn, 'FETCH ALL in myportal');
if (PQresultStatus(res) <> PGRES_TUPLES_OK) then
begin
Writeln (stderr, 'FETCH ALL command didn''t return tuples properly');
PQclear(res);
exit_nicely(conn);
end;
{ first, print out the attribute names }
nFields := PQnfields(res);
for i := 0 to nFields-1 do
Write (PQfname(res, i),space (15-strlen(PQfname(res, i))) );
writeln;
writeln;
{ next, print out the instances }
for i := 0 to PQntuples(res)-1 do
begin
for j := 0 to nFields-1 do
write(PQgetvalue(res, i, j),space (15-strlen(PQgetvalue(res, i,j))));
writeln;
end;
PQclear(res);
{ close the portal }
res := PQexec(conn, 'CLOSE myportal');
PQclear(res);
{ end the transaction }
res := PQexec(conn, 'END');
PQclear(res);
{ close the connection to the database and cleanup }
PQfinish(conn);
end.
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