Daily Archives: 05.01.2017

Delphi. FireDAC. Проверка на NULL и запись NULL значений в базу данных

Posted on 05.01.2017 by Stanislav_Panteleev

Проверка на NULL

with qSomeQuery do begin

if FieldByName('someField').IsNull then
//do something

end;

with qSomeQuery do begin

if FieldByName('someField').IsNull then

//do something

end;

Запись NULL значений, согласно инструкции

  // setting param to null

...
qSomeQuery.SQL.Text:=
'INSERT INTO DATABASE.TABLE (`someParam`) values (:someParam)';
...

//To set the parameter value to Null, specify the parameter data type, then call the Clear method:

with qSomeQuery do begin

         with ParamByName('someParam') do begin
         DataType:=ftInteger;
         Clear();
         Bound:=true;
         end;
ExecSQL;
end;

// setting param to null

...

qSomeQuery.SQL.Text:=

'INSERT INTO DATABASE.TABLE (`someParam`) values (:someParam)';

...

//To set the parameter value to Null, specify the parameter data type, then call the Clear method:

with qSomeQuery do begin

with ParamByName('someParam') do begin

DataType:=ftInteger;

Clear();

Bound:=true;

end;

ExecSQL;

end;

Пример из проекта…

SET foreign_key_checks = 0;


UPDATE `galionsms_db`.`clients` SET `partners_id`=:partners_id WHERE `id`=:id;

SET foreign_key_checks = 1;

SET foreign_key_checks = 0;

UPDATE `galionsms_db`.`clients` SET `partners_id`=:partners_id WHERE `id`=:id;

SET foreign_key_checks = 1;

 with qUpdatePartners_idInClients do begin
 Connection:=DBConnection.FDConnection;

         with ParamByName('partners_id') do begin
         DataType:=ftInteger;
         Clear();
         Bound:=true;
         end;

         Params.ParamValues['id']:=ClientsOfPartner[i];

         ExecSQL;

 end;

with qUpdatePartners_idInClients do begin

Connection:=DBConnection.FDConnection;

with ParamByName('partners_id') do begin

DataType:=ftInteger;

Clear();

Bound:=true;

end;

Params.ParamValues['id']:=ClientsOfPartner[i];

ExecSQL;

end;

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Daily Archives: 05.01.2017

Delphi. FireDAC. Проверка на NULL и запись NULL значений в базу данных

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