Use of SQL Server Features

The driver takes advantage of the following new features in SQL Server:

• The driver uses the SET TRANSACTION ISOLATION LEVEL statement to
  • Expose the READ UNCOMMITTED isolation level
  • Enforce strict serializability

  In earlier versions, the driver "manually" inserted a HOLDLOCK in the FROM clause of SELECT statements when the user had requested the serializable option.

• The driver uses the SET FMTONLY statement to implement the SQLDescribeCol and SQLColAttributes APIs. Previously, these APIs were implemented by issuing a "dummy" query that did not return results.
• The driver enforces the use of ANSI Quoted Identifiers and issues the SET QUOTED_IDENTIFIER ON statement during the startup sequence.
• The driver exposes SQL Server's IEF using the SQLPrimaryKeys and SQLForeignKeys APIs.
• The driver uses the SET ANSI_NULL_DFLT_ON statement to enforce ANSI compliant default nullability for columns. In earlier versions, the driver "manually" inserted the NULL keyword after column specifications.
• The driver allows text and image parameters in stored procedures. Invocation of these stored procedures is handled as an RPC request, as opposed to a language event as in previous versions.
• The driver automatically uses the default packet size set at the server if one is not specified using the ODBC SQLSetConnectOption.