The following figure shows how the database system searches in the B* tree to determine where the new data should be inserted for an INSERT statement.
The address table is defined by the column with the city primary key. The corresponding INSERT statement is be used to insert an entry in the address table with the Arbon value for the city primary key field.
If there is sufficient space for the new entry in the leaf page of the B* tree, the database system inserts the entry at the end of the data area and updates the position list. The address of the new entry is written at the correct position in the position list. In the example above, this is item 4. Position 4 points to the new table entry number 7.
If the database system inserts data in a data page, then this data page is physically filled with data from the top left and with the corresponding position entries from the bottom right. The position list and data area therefore converge if a lot of data is added to a data page.