[Solved]Dbgrid add new records from query without loss of old data
lazarus / 16-Databases

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doniuzas · 2015-02-03 14:23

hello, please help.
i have this structure zconnection1->zquery1->datasource1->dbgrid1
How i can add additional data from query on button click without loss
old data?
I know i need add some like a memodataset or bufdataset or
jvmemorydata, but how whole code?
my query code on button click is:

zquery1.sql.clear;
zquery1.Params.CreateParam(ftstring,'someparam',ptunknown);
zquery1.params.ParamValues['someparam']:=dbtext1.field.asstring;
zquery1.sql.add('select title from table where x= :someparam');
zquery1.active:=true;

thank you in advance for your answers.

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doniuzas · 2015-02-03 17:52

no answers?

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fpcoder · 2015-02-03 18:27

doniuzas, the DBGrid doesn't show anything except whats in the query.
So you actually never add or delete data directly from a DBGrid. It is
just a mirror of the content in its associated SQLQuery. If you want
to add content to the DBGrid then you do it indirectly, by modifying
the SQL select statement. The data then simply shows up in the grid
without you having to do anything.

Its not clear to me exactly what you are doing, but perhaps you could
have a button that closes the current query, assigns a new select
statement and re-opens the query. If you need to keep your position in
the grid, then run the Locate command after re-opening the query.

If you explain a bit more, maybe we can come up with another answer.

Also, you dont need to create the Param if you assign the select
statement first:

Code: [Select]zquery1.SQL.Text:= 'SELECT title FROM table WHERE x=
:someparam'
The select statement doesnt need to be cleared when you assign to
SQL.Text.
And then you can just use the param, it has been created for you
automatically:

Code: [Select]zquery1.ParamByName('someparam').asstring:=
dbtext1.field.asstring;
zquery.Open;

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doniuzas · 2015-02-03 18:50

i can make zquery.Open; zquery.close and re-opening the query but i
need make like a virtual table or someting for save previously
assigned select statment results and show in dbgrid.

my schema is:
zconn1->zquery1->dbgrid1
dbtext1.field.asstring give me string parameter from dbgrid1
(zquery2.ParamByName('someparam').asstring:= dbtext1.field.asstring;)

zconn1->zquery2->dbgrid2
zquery2.SQL.Text:= 'SELECT title FROM table WHERE x= :someparam'
i need make someting like this:
zconn1->zquery2-> virtual table or virtual dataset(for adding executed
zquery2 statments results)->dbgrid2

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balazsszekely · 2015-02-03 19:56

Still not clear what are you after! Lets say you have a table: POEPLE,
with the following fields ID, NAME, AGE(integer, varchar(32), integer)
ID     NAME    AGE
1       AAA      25
2       BBB      43
3       CCC     15
4       DDD     64 
5       FFF       22

zconn1->zquery1->dbgrid1
Your zquery1 SQL looks like this: select * from PEOPLE where age <=
:pAge
Code: [Select]//...
zquery1.ParamByName('pAge').AsInteger := 25
zquery.Open;
//..
Now your grid will be populated with the following values:
1       AAA      25
3       CCC     15
5       FFF       22

Do you wish to add more data to table People, with the possibility to
show the current configuration at later time? Please be more specific.
Try do describe it with a few example. How table people should look
like, what do you want to see in the grid, etc...

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doniuzas · 2015-02-03 20:57

OK with this example I have database with two tables, first is
people(names,age), second is details(age, adress). from first query  I
get results with age <=25 and populated to dbgrid1, now from
dbtext.field.as string (pointed to dbgrid1) I'm get parameter for
second query (query2). query2 pointed to dbgrid2. now if I execute
query2 with param 25 I'm see in dbgrid2 25 and adress1, I need make
second query2 with param 15 but need keep populated info in dbgrid2
(25 and adress1).
Need something like virtual table(keep info in memory) between query2
and dbgrid2.
Query2 inserting(updating) into virtual table(dataset) and this
virtual table is pointed to dbgrid2. But how this make? need full
code.
may by now its clear?

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doniuzas · 2015-02-03 21:01

... if its not clear... I have two query components and two dbgrid
components dropped in to form...

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mangakissa · 2015-02-05 08:27

I'll try to undersand why you want old data on screen, but if you look
at my unit, you can find a way to create a memorytable (TBufdataset).
Just rename it to .pas file

I think it's better to use a master / detail relation of the two
tables.

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doniuzas · 2015-02-05 10:46

why old data on screen need?
ok this is application for collecting data from database with
different statments and all this "data pack" print as barcode(prices)
labels. this apps is for two big supermarkets.

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doniuzas · 2015-02-05 10:56

sorry mayby im noob, but i not understand your unit, for my is too
hard

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mangakissa · 2015-02-05 12:17

Wait. Your developping for two big supermarkets and you can't
understand my (very) simple class code?
This is what you need for memorytable (TBufdataset)
Code: [Select]constructor TGlobals.Create;
begin
  inherited;
    ClDataSet := TBufDataset.Create(nil);
  with ClDataSet do
  begin
    FieldDefs.Add('field1',ftString, 50);
    FieldDefs.Add('field2',ftString, 50);
  end;
  ClDataset.CreateDataset;
  ClDataSet.Active := true;
end;

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doniuzas · 2015-02-05 13:03

im not asking how create bufdataset, i need code sample how from query
to bufdataset replace info (insert,copy,append or etc.)

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mangakissa · 2015-02-05 13:47

TBufdataset is not like TClientdataset in Delphi.
QuoteI know i need add some like a memodataset or bufdataset or
jvmemorydata, but how whole code?Code: [Select]procedure
AddSomethingToMemtable(aDataset : TDataset);
var index : integer;
begin
  while not aDataset.eof do
  begin
      for index := 0 to aDataset.fieldcount - 1 do
        Bufdataset[index].Value := aDataset[index].Value;
  end;
end;
Jus behave tbufdataset as a normal TDataset