How can I achieve unicode normal form C with collation in MySQL, db2, Derby or Oracle databases?

Question

I have tried using different collation methods across different implementations of SQL databases, but am unable to achieve complete normalization. Does anyone have any tips for this in any of the above implementations?

Answer 1

The best way is to TEST each RDBS with different collating sequence. Some of them could not be aware about different collate sequences (DB2, Oracle), and others can support many of them (Derby).

For example, in DB2, you can provide many different collating sequence at the database creation time. Once the database is created, you cannot modify the locale settings (I wrote an article about that in DB2 )

Remember that there are different kinds of methods to stored Unicode characters. Unicode is a table, but storage Unicode is something different, and this is the origin of your problem. You must test with th UCA (Unified Collation Algorithm) of the different RDBS.

• UCA https://en.wikipedia.org/wiki/Unicode_collation_algorithm
• DB2 http://www-01.ibm.com/support/knowledgecenter/SSEPGG_10.5.0/com.ibm.db2.luw.admin.nls.doc/doc/c0006812.html
• Oracle http://docs.oracle.com/database/121/NLSPG/ch5lingsort.htm#NLSPG267
• MySQL https://dev.mysql.com/doc/refman/5.7/en/adding-collation-unicode-uca.html