Table access using a B* tree is illustrated using the example of an INSERT statement.
The address table is defined by the column with the city primary key. An INSERT statement is used to insert into the address table an entry with the value Arbon for the primary key field city.
If there is enough 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 section and updates the position list. The address of the new entry is written to the correct position in the position list. In the example above, this is position 4. Position 4 points to the new table entry number 7.
When the database system adds data to a data page, the data page is filled physically from the top left with data and from the bottom right with the corresponding position entries. The position list and the data area converge when a lot of data is inserted into a data page.