Knobit of Data modelling · K-819 · Skill

Recognises a collation changing what a key means

What it means

The case and accent sensitivity of the columns in a key, which on most engines comes from a server or database default nobody chose here. Case-insensitive makes an IBAN and its lower-case form one key; case- and accent-sensitive makes `Mägi` and `Magi` two parties. Either can be right; an unexamined default cannot.

How it is assessed

Flags the deficient case and passes the acceptable one. Deficient: SQL Server with the usual case-insensitive database collation: `uk_dim_party_reference` treats `ee-00412` and `EE-00412` as one party, and a migration from a case-sensitive source merges two customers into one with no error Acceptable: Identifiers normalised on load (IBAN upper-cased, spaces removed) so the key does not depend on collation, and the collation named in `physical_options` for the engines that accept it — making the key's meaning a decision in the model rather than a server setting

Builds on

Explains collation and case or accent sensitivityK-855 · Knowledge

Needed by

None