identities

"_identity_method" is set to @@identity, as "SCOPE_IDENTITY()" doesn't work with DBD::ADO. See "IMPLEMENTATION NOTES" in DBIx::Class::Storage::DBI::MSSQL for caveats regarding this.

truncation bug

There is a bug with MSSQL ADO providers where data gets truncated based on the size of the bind sizes in the first prepare call:

<https://rt.cpan.org/Ticket/Display.html?id=52048>

The "ado_size" workaround is used (see "ADO providers" in DBD::ADO) with the approximate maximum size of the data_type of the bound column, or 8000 (maximum VARCHAR size) if the data_type is not available.

Please report problems with this driver and send patches.

LongReadLen

"LongReadLen" is set to "LongReadLen * 2 + 1" on connection as it is necessary for some LOB types. Be aware of this if you localize this value on the $dbh directly.

binary data

Due perhaps to the ado_size workaround we use, and/or other reasons, binary data such as "varbinary" column data comes back padded with trailing "NULL" chars. The Cursor class for this driver (DBIx::Class::Storage::DBI::ADO::Microsoft_SQL_Server::Cursor) removes them, of course if your binary data is actually "NULL" padded that may be an issue to keep in mind when using this driver.

uniqueidentifier columns

uniqueidentifier columns come back from ADO wrapped in braces and must be submitted to the MSSQL ADO driver wrapped in braces. We take care of this transparently in this driver and the associated Cursor class (DBIx::Class::Storage::DBI::ADO::Microsoft_SQL_Server::Cursor) so that you don't have to use braces in most cases (except in literal SQL, in those cases you will have to add the braces yourself.)

fractional seconds

Fractional seconds with DBIx::Class::InflateColumn::DateTime are not currently supported, datetimes are truncated at the second.