QML SQLite database inserting new columns to database

Yunus

Hi Qt Forum! I am trying to use SQLite database by taking reference this link. I dont want to paste all the code because its exactly same and working well.

My problem is this example is prepared for 3 columns and I want to make it 4 or more columns but when I tried to insert new columns(I added the same type of codes in cpp side and also qml side) and click add button. It gives me the warning:

error insert into NameTable
" Parameter count mismatch"

How can I add new columns to this example?

jsulm

@Yunus New columns are not inserted using INSERT INTO, but https://www.w3schools.com/sql/sql_alter.asp

Yunus

@jsulm Thanks for quick reply. I will check the document you shared but can you guide me more specifically because I am still a beginner.

jsulm

@Yunus Well, it is shown in the link I posted:

ALTER TABLE table_name
ADD column_name datatype;

What exact support do you need?
Keep in mind that you can simply create the tables with all needed columns.

Yunus

@jsulm I mean where I should add these piece of code. Because in this example there is no method similar to it

jsulm

@Yunus It's a SQL query, so you do it in the same way you do with your other queries in your Qt app.

Yunus

@jsulm In my example, I think its doing it in createTable() function but how the way I can use the code document suggested. I still couldnt understand how the example adding the columns

jsulm

@Yunus This is how a table is created in the example you posted:

    if(!query.exec( "CREATE TABLE " TABLE " ("
                            "id INTEGER PRIMARY KEY AUTOINCREMENT, "
                            TABLE_FNAME     " VARCHAR(255)    NOT NULL,"
                            TABLE_SNAME     " VARCHAR(255)    NOT NULL,"
                            TABLE_NIK       " VARCHAR(255)    NOT NULL"
                        " )"
                    )){

If you want to add one more column to this table then simply change that query:

    if(!query.exec( "CREATE TABLE " TABLE " ("
                            "id INTEGER PRIMARY KEY AUTOINCREMENT, "
                            TABLE_FNAME     " VARCHAR(255)    NOT NULL,"
                            TABLE_SNAME     " VARCHAR(255)    NOT NULL,"
                            TABLE_NIK       " VARCHAR(255)    NOT NULL",
                            " my_own_column VARCHAR(255) NOT NULL" 
                        " )"
                    )){

Adjust this line as needed:

"my_own_column VARCHAR(255) NOT NULL"

Yunus

@jsulm This was what I tried also. I finally found the problem. I have forgotten to add my column to prepare part which I commented below:

bool DataBase::inserIntoTable(const QVariantList &data)
{
    QSqlQuery query;

    query.prepare("INSERT INTO " TABLE " ( " TABLE_FNAME ", "
                                             TABLE_SNAME ", "
                                             TABLE_NIK ", "
                                             TABLE_MATCH  " ) "
                  "VALUES (:FName, :SName, :Nik, :Matching)"); // I have forgotten to add my new column to end of  this line
    query.bindValue(":FName",       data[0].toString());
    query.bindValue(":SName",       data[1].toString());
    query.bindValue(":Nik",         data[2].toString());
    query.bindValue(":Matching",    data[3].toString());



    if(!query.exec()){
        qDebug() << "error insert into " << TABLE;
        qDebug() << query.lastError().text();
        return false;
    } else {
        return true;
    }
    return false;
}

Thank you so much also @jsulm