Wide Char mode of SNC driver

The snc.widechar FGLPROFILE entry defaults to the right setting for the current application locale.

SQL Server performs better, when using the correct ODBC types in SQLBindParameter(), depending on the database columns types:
  • When using CHAR/VARCHAR/TEXT SQL types (typically, when the application locale uses a single-byte encoding), the recommendation is that ODBC SQL types SQL_[VAR]CHAR (single-char ODBC SQL types) are used
  • When using NCHAR/NVARCHAR/NTEXT SQL types (when the application locale uses a multi-byte encoding such as UTF-8), it is recommended to use the ODBC SQL types SQL_W[VAR]CHAR (these are wide-char ODBC SQL types)

The dbi.database.dbname.snc.widechar FGLPROFILE entry controls the ODBC SQL types used by the SNC driver.

Before version 3.10, the snc.widechar option was set to true by default, assuming that the application locale uses a multi-byte encoding like UTF-8. If the database columns are defined with CHAR/VARCHAR/TEXT types, this parameter had to be set to false.

Starting with 3.10, to simplify application configurations when using a single-byte encoding, the snc.widechar option defaults to the expected setting, based on the current application locale (assuming that the database column types fit the application locale):
  • If the application locale defines a single-byte encoding (such as ISO8859-1), we assume that the database columns are defined with CHAR/VARCHAR/TEXT types to store single-byte characters, and the SNC driver will use SQL_[VAR]CHAR.
  • If the application locale defines a multibyte encoding (such as UTF-8 or BIG5), we assume that the database columns are defined with NCHAR/NVARCHAR/NTEXT types to store UNICODE characters, and the SNC driver will use SQL_W[VAR]CHAR.
Note: Set the dbi.database.dbname.snc.widechar to false, only if you are using a multibyte encoding such as BIG5, with CHAR/VARCHAR/TEXT column types in the database.
Note: Easysoft (ESM) and FreeTDS (FTM) drivers do not support the snc.widechar option: The SQL char type binding mode is automatic, depending on the current application locale, and it cannot be changed.