DBNavigator, Dbgrid_Explain me..!
lazarus / 16-Databases

----------------------------------------------------------------------
BlackCat · 2008-07-15 20:43

hi everybody..!!

i have a big problem, I check the example "adrees_book" in lazarus
Folder, but it use DBF tables/databases,.
I was thinking use this components:

DBNavigator,
DBGrid,
SqlQuery,
Datasource,
MysqlConnection,
SqlTransaction,

 At the same time,  I can use DBNavigator with the DBGrid and SqlQuery
but when I use  for UPDATE,EDIT, Or DELETE,  this shows me a error.:
"Operation can't be peroformer on an active dataset "

I need use the DGrid and DBEdit with the DBNAvigator ar the same
time,for example: look the Mysql table in te DBGrid and change  one
register on this moment,..


I Tried use this code from TRYMSQL example from   lazarus wiky.
 

SQLQuery1.Upda]"]>Blockedde:=upWhereChanged;
    SQLQuery1.ApplyUpdates;
    SQLTransaction1.Commit;
    Showmessage('ddd');
// set read-only and parsesql back to default
    SQLQuery1.ParseSQL:=false;
    SQLQuery1.ReadOnly:=true;         

but nothing happended, and the same error appeared...

I read in the forum tha SQLQUERY not allow the UPDATE, EDIT, DELETE,
only

I'll going crazy about this....!!

1. Is possible use those componets at the same time? or
2. I need download my table in other componens to use UPDATE, EDIT?
3. What about use this:
        sqlquery1.sql.text:='select * from mytable LIMIT 5'; //limit
in mysql is to see the first 5 records in the table,
        sqlquery.open;
        made me an error about "LIMIT ..."
I check in mysql console first, then I check in Lazarus if is a valid
instruction, WHat about this? somebody can help me??

Thanks...!!
 BlackCat.. :cry:

----------------------------------------------------------------------
BlackCat · 2008-07-18 17:00

No more about my problem.. I found the answer....
Thanks

----------------------------------------------------------------------
chris.kirkpatrick · 2008-08-06 09:42

I'm very happy that you found an answer,

It would be very helpful if you could share your answer with the rest
of us!


Chris

----------------------------------------------------------------------
anderson5420 · 2008-08-08 04:30

Yes, I second Chris's suggestion here.  I can get everything to work
right up to where I want to edit or insert a record (using a a dbGrid
and a dbNavigator on a results form). If I don't use any of the above
code for the dbNavigator BeforeAction event, no errors but nothing
gets written back to the MySQL database. When I try the BeforeAction
event handler code, I get the same error "Operation can't be performed
on an active dataset." If I close the dataset (sqlquery), the error
becomes "Can't perform operation on an inactive dataset"!  So what
state of dataset CAN the operation be performed on?  I would just love
to see the code that actually works to apply updates and commit them
to the underlying database, which is, you know, sort of the whole
point!

Pat

----------------------------------------------------------------------
BlackCat · 2008-08-18 06:05

SURE.. THIS IS MY EXAMPLE ABOUT MYSQL AND SQLDB...
i try explain you how i made my form, ok, sorry my bad english...
i 'm using W Vista, and also work in W Xp SP2, using Lazarus 0.9.24
Instalation i don't change anything else...
in some first examples about mysql i made, i add mysql.dll, if you
have a problem when run your project similar to "project...
mysql.dll... not found" you need add in your Project Folder the
mysql.dll ok? but in this example, i check and i don't use anymore
mysql.dll i forgot why i need it in my first examples 

First
1.- I made a form using SQLQUERY, SQLTRANSACTION, SQLCONNECTION and
DATASOURCE with NAVIGATOR and DBGRID and DBEDIT'S alias ==[7PACK]
check the finish this email, this reference
2.-connect all the component except in the SQLQUERY.datasource:=(none)
in blank, don't but nothing, ok.
3.-change also in the Slquery properties this values:
Upda]"]>Blockedde:=UpWhereChange
UsePrimaryKeyAsKey:=true
>>(NOTE: IS VERY IMPORTANT ADD A PRIMARY KEY IN YOUR TABLE FROM MYSQL,
IS THE REFERENCES TO CHANGE ON EDIT, UPDATE,ETC.IN MYSQL-SQLQUERY,
OK?)
4.- in sqlconnection change:
Streamedconnected:=true

Now, you only need change in the sqlquery EVENTS, i use these events:
After(Close,Delete,Edit,Insert,Post) i dont' know what happend with
"before" events in sqlquery, with after events work good in my form.

5.-this is the code i use un each events AFTER:

procedure TForm1.SQLQuery1AfterDelete(DataSet: TDataSet);
begin
SQLQuery1.ApplyUpdates;
SQLTransaction1.Commit;
end; ;

procedure TForm1.SQLQuery1AfterPost(DataSet: TDataSet); //DESPUES DE
POST
begin
SQLQuery1.ApplyUpdates;
SQLTransaction1.Commit;
end;

Right???
don't use Navigator.click event, i spend my time, and i can't found
the correct solution to use it.. ok? is an advice for you only, 

add only AfterPost and AfterDelete Events in Slquery and work
fine...!! but, i use also dbedit's:
6.- in dbedit's fill in the next properties:

datafield:=[your datafield in your table in mysql e.g. mytable(name
var(15), addres var(20),...etc,etc ...... primary key (name) )]
dbedit1.datafield:=name
dbedit1.datasource:=(none) [why?, i use a button using this
instructions.... SqlQuery.Close, SqlQuery.sql.Text:="select * from
mytable"..., SqlQuery.Open dbedit.DataSource:=datasource1;..... ok? an
also work if you add the datasource in design time, but I HAVE A
PROBLEM HERE, ABOUT DBEDITS AND MULTIPLES DGRID USING PAGECONTROL.. I
ASK YOU AT FINISH]

and works..!!

¿Now, Can you help me about the next problem....?
Now, my problem about BDEDIT's is because i use multiples Sheet's in
the page control with diferents tables, i can't re-use the same
Sql,Trans, Connect, Datas... with diferents dbgrid and dbedit's,
because the program .exe give me and error about..."can't found name
fields in you....etc, etc"
i was thinking about that, i think is because the sqlquery don't free
the field in the dbedit and don't break the "connection in the
¿buffer?(the relation in execute time)" between the Query-DBedit..
like "persistant connection"... right??

try use [7PACK] in a pagecontrol using in the first sheet one table,
and in the second sheet another table,
try use the same bdedit's for your tables, put this outside the page
control, directly in the form, or in each sheet... ok? how you ever
use pagecontrol in delphi?..is similar...
TO SOLVE MY PROBLEM I USE multiples [7PACK] for each table in each
sheet in the pagecontrol.. but my question is.. what about the Ram?? i
am wrong if i use multiples 7PACKS???the conexion is PERMANENT and
PERSISTENT with .exe and Mysq with my multiples 7PACKS i use...??

IF YOU KNOW OTHER EXAMPLES, ABOUT MYSQL AN LAZARUS, I FEEL VERY
INTERESTING ABOUT THIS, PLEASE CONTACT ME...
because, i feel i feel confuse if my personal conclusions are good or
bad.. i check a lot of forums in spanish and english about this, but i
found only pieces of information about this and allow me make my
example and the posibility to explain you and other.. check in lazarus
Forum in Lazarus Wiki in Database questions, I'm BlackCat User in the
forum..

is all about your questions and my possible solution...
Please, if you made or checked Mysql components, said me what do you
thing about my "solution" or your opinion. please...

Regards...
Mrf from Slp, Mexico