I'm trying to call a stored procedure from some delphi code
I have a function like
procedure TDatabaseConnection.GetHourlyFiltergramLabSamples(StartTime, EndTime : TDateTime; Samples : TList<THourlyFilterCount>);
var
StoredProc : TADOStoredProc;
begin
StoredProc := TADOStoredProc.Create(nil);
try
StoredProc.Connection := Connection;
StoredProc.ProcedureName := 'GetHourlyFiltergramLabSamples';
StoredProc.Parameters.Refresh;
StoredProc.Parameters.ParamByName('#StartTime').Value := startTime;
StoredProc.Parameters.ParamByName('#EndTime').Value := EndTime;
StoredProc.Open;
while not StoredProc.Eof do
begin
//Do stuff with the results here ...
StoredProc.Next;
end;
finally
FreeAndNil(StoredProc);
end;
end;
When I hit the line StoredProc.Open;
I get an error
'CommandText does not return a result set.'
I have checked using SQL server management studio that the stored procedure does in fact return results.
I've found that this issues seems to be temperamental. Surely this isn't a bug in the database connector??
I'm out of ideas
I've had this one open for a number of months now.
The best solution I have is to switch to using FireDAC. I have not had the same issues when using FireDAC to execute stored procedures.
instead I use the TFDStoredProc type to run stored procedures
Related
My program keeps making new requests to a database while it's running. Now, I am wondering if I should outsource my database connection, since it always creates a new one for a new query and destroys it afterwards.
function TMainMenu.btnInsertPersonClick(Sender: TObject)
var
vDatabase : TADOConnection;
vQuery : TADOQuery;
begin
vDatabase := TADOConnection.Create(self);
vQuery := TADOQuery.Create(self);
try
vDatabase.ConnectionString := 'SECRET_STRING';
vQuery.Connection := vDatabase;
// DO QUERY STUFF HERE
finally
vDatabase.Close;
vQuery.Destroy;
vDatabase.Destroy;
end;
end;
Maybe it's not a good idea to outsource the connection. That's why I am happy about any help or suggestions. Sheers!
How can I use Firedac LocalSQL with FDMemtable? Is there any working example available?
According to the Embarcadero DocWiki I set up a local connection (using SQLite driver), a LocalSQL component and connected some Firedac memory tables to it. Then I connected a FDQuery and try to query the memory tables. But the query always returns "table xyz not known" even if I set an explicit dataset name for the memory table in the localSQL dataset collection.
I suspect that I miss something fundamental that is not contained in the Embarcadero docs. If anyone has ever got this up and running I would be grateful for some tips.
Here is some code I wrote for an answer here a while ago, which is a self-contained example of using LocalSQL, tested in D10.2 (Seattle). It should suffice to get you going. Istr that the key to getting it working was a comment somewhere in the EMBA docs that FD's LocalSQL is based on Sqlite, as you've noted.
procedure TForm3.CopyData2;
begin
DataSource2.DataSet := FDQuery1;
FDConnection1.DriverName := 'SQLite';
FDConnection1.Connected := True;
FDLocalSQL1.Connection := FDConnection1;
FDLocalSQL1.DataSets.Add(FDMemTable1);
FDLocalSQL1.Active := True;
FDQuery1.SQL.Text := 'select * from FDMemTable1 order by ID limit 5';
FDQuery1.Active := True;
FDMemTable1.Close;
FDMemTable1.Data := FDQuery1.Data;
end;
procedure TForm3.FormCreate(Sender: TObject);
var
i : integer;
MS : TMemoryStream;
begin
FDMemTable1.CreateDataSet;
for i := 1 to 10 do
FDMemTable1.InsertRecord([i, 'Row:' + IntToStr(i), 10000 - i]);
FDMemTable1.First;
// Following is to try to reproduce problem loading from stream
// noted by the OP, but works fine
MS := TMemoryStream.Create;
try
FDMemTable1.SaveToStream(MS, sfBinary);
MS.Position := 0;
FDMemTable1.LoadFromStream(MS, sfBinary);
finally
MS.Free;
end;
end;
As you can see, you can refer in the SQL to an existing FireDAC dataset simply by using its component name.
I am trying to make anonymous blocks to update esri's oracle versioned views. The code runs fine when I execute it from pl/sql developer without the begin/end. But as soon as I add the begin/end I get errors.
begin
call sde.version_util.set_current_version ('ARCFM8.vtemp');
call sde.version_user_ddl.edit_version ('ARCFM8.vtemp', 1);
update arcfm8.t_conductormarker_vw set CEAREFERENCEDRAWING = 'my fisrt multiversion view update'
where OBJECTID = 3;
call sde.version_user_ddl.edit_version ('ARCFM8.vtemp', 2);
end;
Call is an SQL keyword not a PLSQL keyword. It will work outside the anonymous block, but not inside it. PLSQL will take care of this for you so all you should need is...
begin
sde.version_util.set_current_version ('ARCFM8.vtemp');
sde.version_user_ddl.edit_version ('ARCFM8.vtemp', 1);
update arcfm8.t_conductormarker_vw set CEAREFERENCEDRAWING = 'my fisrt multiversion view update' where OBJECTID = 3;
sde.version_user_ddl.edit_version ('ARCFM8.vtemp', 2);
end;
I'm developing an application (for Win32 and WinCE) in Lazarus using sqldb components for data access.
Remote database is PostgreSQL (but i have the same behaviour with local SQLite).
Connection to PostgreSQL work perfectrly but when I open any Query (also a very simple select) database go in transaction: "idle in transaction".
var
PGConnection:TPQConnection;
PGTransaction:TSQLTransaction;
myQuery:TSQLQuery;
begin
PGConnection := TPQConnection.Create(self);
PGTransaction := TSQLTransaction.Create(self);
myQuery := TSQLQuery.Create(self);
try
PGConnection.HostName := '192.168.1.2';
PGConnection.DatabaseName:='testdb';
PGConnection.UserName:='test';
PGConnection.Password:='test';
PGConnection.Transaction := PGTransaction;
PGConnection.Open;
myQuery.DataBase := PGConnection;
myQuery.SQL.Add('SELECT 1 AS value');
myQuery.Open; // <- this start transaction
ShowMessage(myQuery.FieldByName('value').AsString); // <- db: "idle in transaction"
myQuery.Close; // <- db: "idle in transaction"
PGConnction.Close;
finally
myQuery.Free;
PGConnection.Free;
PGTransaction.Free;
end;
end;
Ok, maybe sqldb work in this way: every query on database start a transaction, so, developer must Commit or Rollback after interrogation. But there is another question: when I commit the Transaction, sqldb close the query and i can't access value retrieved:
var
PGConnection:TPQConnection;
PGTransaction:TSQLTransaction;
myQuery:TSQLQuery;
begin
PGConnection := TPQConnection.Create(self);
PGTransaction := TSQLTransaction.Create(self);
myQuery := TSQLQuery.Create(self);
try
PGConnection.HostName := '192.168.1.2';
PGConnection.DatabaseName:='testdb';
PGConnection.UserName:='test';
PGConnection.Password:='test';
PGConnection.Transaction := PGTransaction;
PGConnection.Open;
myQuery.DataBase := PGConnection;
myQuery.SQL.Add('SELECT 1 AS value');
myQuery.Open; // <- this start transaction
PGConnection.Transaction.Active := False; // <- Close also myQuery
ShowMessage(myQuery.FieldByName('value').AsString); // <- Error: Field "value" not found
myQuery.Close;
PGConnction.Close;
finally
myQuery.Free;
PGConnection.Free;
PGTransaction.Free;
end;
end;
This behavior is a bit boring: I can't use TSQLQuery dataset with dbgrid (since I do not want my database in transaction for too long) so I need to move selected data in Memory Tables.
Is this a bug, I made some mistakes or is a normal operation? There is a way to open a SELECT Query and use it without start a transaction?
This is currently normal behaviour.
I have planned an 'offline' mode where the transaction is closed but the data is kept open.
What you can currently do is save the data to file (using the savetofile method), disconnect, and load the data again from file (using the loadfromfile method)
Consider a trigger that sets an id-column to an Oracle-sequence (next-)value on-insert. Now I want to extend it with some extra debugging actions. But they should be only active for certain connection/sessions (i.e. debugging ones).
Pseudo-Code on client side:
Open connection to oracle database
set mydebugflag=yes for that connection only
insert some stuff
close connection
Pseudo-Code on server-side (inside the trigger):
set id = someseq.next_val
if mydebugflag=yes then { do_some_extra_sanity_checks(); diagnostics();}
else: finished
How to implement such logic for an Oracle database?
Which Oracle features should I use for this?
There are a couple of ways to do this.
One is to create a package, create a package global variable (which will have session scope) in the package, and then have your client set the package variable and your trigger read it. Something like
CREATE OR REPLACE PACKAGE pkg_debug_mode
AS
PROCEDURE set_debug_mode( p_debug_mode IN NUMBER );
FUNCTION get_debug_mode
RETURN NUMBER;
DEBUG_MODE_ON constant number := 1;
DEBUG_MODE_OFF constant number := 2;
END;
CREATE OR REPLACE PACKAGE BODY pkg_debug_mode
AS
g_debug_mode NUMBER := DEBUG_MODE_ON;
PROCEDURE set_debug_mode( p_debug_mode IN NUMBER )
AS
BEGIN
g_debug_mode := p_debug_mode;
END;
FUNCTION get_debug_mode
RETURN NUMBER
IS
BEGIN
RETURN g_debug_mode;
END;
END;
The client calls pkg_debug_mode.set_debug_mode to set the debug mode and the trigger calls pkg_debug_mode.get_debug_mode to determine the current debug mode for the session.
create or replace context my_ctx using pkg_debug_mode;
CREATE OR REPLACE PACKAGE BODY pkg_debug_mode
AS
PROCEDURE set_debug_mode( p_debug_mode IN NUMBER )
AS
BEGIN
dbms_session.set_context( 'MY_CTX', 'DEBUG_MODE', p_debug_mode );
END;
FUNCTION get_debug_mode
RETURN NUMBER
IS
BEGIN
RETURN SYS_CONTEXT( 'MY_CTX', 'DEBUG_MODE' );
END;
END;
Your trigger can either call the get_debug_mode function or it can directly reference the context by putting the SYS_CONTEXT call in the trigger.