Hi
We are trying to build a many-to-many relationship between multiple tables , as per a school textbook published in India.
The text book is accessible via below url:
http://cbseacademic.nic.in/web_material/Curriculum21/publication/secondary/402-IT_ClassX.pdf
Refer page 138, we are unable to recreate a many to many as mentioned in the textbook. It says no primary key required.
How can we create many-to-many without primary key in a table / without using a third joining table?
https://forum.openoffice.org/en/forum/viewtopic.php?f=39&t=105165&p=510419
https://forum.openoffice.org/en/forum/viewtopic.php?f=100&t=40444
Thanks for the reply. However we are trying to achieve what the text book has described.
Seems the person, who created the script, doesn’t work really with the internal database of LO (or OpenOffice). There are tables without primary keys and you couldn’t input data into this tables through the GUI in LO or OpenOffice.
Also it is very irritating to name the fields “ID” but have set it to be not a value for identifying a row.
You can’t really use the example of the script in Base with internal database. You wouldn’t be able to add any row to a table without a primary key with internal database. So do it with 3 tables, one table, which would contain the primary keys of the other tables together as primary key. This will work.
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A many-to-many relationship requires the creation of a third table, that is, a relationship table (decomposition table). We get: Many-to-One and One-to-Many. In addition to key-key pairs, a relationship table can have associative fields.
When joining tables without primary keys, we get a Cartesian join: Every record in the first table is joined with every record in the second table. We get: the product of the number of records in one table by the number of records in another. This dataset is not editable.
The example in your tutorial is not the best one. After all, an employee works in one department.
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Simply don’t and follow the rules of proper database design.
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