Updating the table

There are three primary methods that modify the table data. They are write_row(), delete_row(), and update_row(), which are used by the INSERT, DELETE, and UPDATE statements accordingly. In our engine, write_row() is the most complex one.

int ha_html::write_row(uchar *buf)
{
if (table->timestamp_field_type &
TIMESTAMP_AUTO_SET_ON_INSERT)
table->timestamp_field->set_time();
if (table->next_number_field && buf == table->record[0]) {
int error;
if ((error= update_auto_increment()))
return error;
}

Almost every engine's write_row() method starts with these lines. They update the values of the TIMESTAMP and AUTO_INCREMENT fields, if necessary. Strictly speaking, the second—AUTO_INCREMENT—block is not needed here. Our engine does not support indexes, that is, it can never have an AUTO_INCREMENT field.

fseek(fhtml, -FOOTER_LEN, SEEK_END);
fprintf(fhtml, "<tr>");

We write a new row at the end of the file. That is, we position the stream...