how to add data Into database using a dialog

[ChrisW67]

sql = "INSERT INTO mytable (code,name) VALUES ('" + mydlg.getCode() + "','" + mydlg.getName() + "')"; //Creates the sql insert

sql = "INSERT INTO mytable (code,name) VALUES ('" + mydlg.getCode() + "','" + mydlg.getName() + "')"; //Creates the sql insert

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It also creates reliability and security issues if you get into the habit of building queries this way. If one of the user's name entries was "Miles O'Brien (Star Trek)" (without the enclosing quotes) the INSERT will fail. If the INSERT was a DELETE the consequences could be dire:

sql = "DELETE FROM mytable WHERE code = '" + mydlg.getCode() +"'";

sql = "DELETE FROM mytable WHERE code = '" + mydlg.getCode() +"'";

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seems safe enough until someone exploits the weakness by typing "x' OR code is not null; -- " in as the code, making the query:

DELETE FROM mytable WHERE code = 'x' OR code is not null;-- '

DELETE FROM mytable WHERE code = 'x' OR code is not null;-- '

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and trashes much data (on most RDMS systems). Might not matter on your single-user desktop app, but it matters greatly in the broader world.

QSqlQuery provides Approaches to Binding Values that ensure user input is safely handled: please use them.