Read an Excel xlsx with PL/SQL

At the OTN SQL and PLSQL forum I promised to publish some code I use for a project I’ still working on. This code allows you to select the content from an Excel document

select * from table( as_read_xlsx.read( as_read_xlsx.file2blob( 'DOC', 'Book1.xlsx' ) ) );

  SHEET_NR SHEET_NAME ROW_NR COL_NR CELL  CEL STRING_VAL NUMBER_VAL DATE_VAL
---------- ---------- ------ ------ ----- --- ---------- ---------- --------------------------
         1 Mijn naam       1      1 A1    N                      11
         1 Mijn naam       1      2 B1    N                      12
         1 Mijn naam       1      3 C1    N                      13
         1 Mijn naam       2      1 A2    N                      21
         1 Mijn naam       2      2 B2    N                      22
         1 Mijn naam       2      3 C2    N                      23
         1 Mijn naam       3      1 A3    N                      31
         1 Mijn naam       3      2 B3    N                      32
         1 Mijn naam       3      3 C3    N                      33
         1 Mijn naam       4      4 D4    S   D4
         1 Mijn naam       6      2 B6    D
         1 Mijn naam       7      2 B7    D
         1 Mijn naam       8      2 B8    D
         1 Mijn naam       9      2 B9    D
         1 Mijn naam      10      2 B10   D
         2 Sheet3          2      2 B2    S   Test
         2 Sheet3          3      3 C3    D                         19-JAN-2013 20:17:00
         2 Sheet3          4      1 A4    S   Anton

18 rows selected.

So here it is

Anton

** Changelog:
** 2013-02-18 – Ralph Bieber
Handle cell type “str” to prevent ORA-06502
if cell content is a string calculated by formula,
then cell type is “str” instead of “s” and value is inside tag
** 2013-02-19 – Ralph Bieber
Add column formula in tp_one_cell record, to show, if value is calculated by formula
** 20-02-2013 – Anton Scheffer
Handle cell types ‘inlineStr’ and ‘e’ to prevent ORA-06502
** 2013-03-19 – Anton Scheffer
Support for formatted and empty strings
Handle columns per row to prevent ORA-31186: Document contains too many nodes