SQL Server: What are ODBC canonical functions?

What are ODBC canonical functions (like {fn NOW()})?开发者_开发技巧

Basically these canonical functions are a set of functions that Microsoft promise will work on all the types of data source that their providers support. This means that you don't have to differentiate your code depending on which data provider you are actually using.

These functions are not a part of basic SQL and therefore you should try to find alternatives that will work standard implementations of SQL or T-SQL.

From MSDN:

Canonical functions are functions that are supported by all data providers, and can be used by all querying technologies. Canonical functions cannot be extended by a provider.

The link above refers to ADO canonical functions, but term canoncial used alongside the term function still relates to the same principle with ODBC.