a 'valid' connection alive SQL for HSQLDB
more ms-sql adapter rerfactoring (table_name / quoting related) :
- make sure it's clear when table_name need to get un-quoted/qualified
- introduce Utils (with not-just a bunch of unquoting helper methods)
- explicit table_exists? since super might change
[MSSQL] fix table/column name quoting - do not quote if quoted already
do not call_discovered_column_callbacks for extending column impls
re-invent some OOP for caseConvertIdentifierForJdbc
need test-unit-context gem for some new (shoulda copied) ms-sql tests
[mssql] get_primary_key hack only needed for 2000 - thus move from utils
+ support Model.table_name to be set quoted as well as unquoted
[DB2] seems like DB2 on ZOS used a non-existing get_primary_key method
[mssql] more quoting tests + table_exists? shall return a true/false
[mssql] multiple (db) connections test (to guard against regressions #329)