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Updating an Application to SQL Server 2008 R2 Native Client from SQL Server 2005 Native Client

This topic discusses the breaking changes in SQL Server Native Client since SQL Server Native Client in SQL Server 2005.

When you upgrade from Microsoft Data Access Components (MDAC) to SQL Server Native Client, you might also see some behavior differences. For more information, see Updating an Application to SQL Server Native Client from MDAC.

Changed behavior in SQL Server Native Client 10.0

Description

OLE DB pads only to the defined scale.

For conversions where converted data is sent to the server, SQL Server Native Client 10.0 pads trailing zeros in data only up to the maximum length of datetime values. SQL Server Native Client 9.0 and earlier padded to 9 digits.

Validate DBTYPE_DBTIMESTAMP for ICommandWithParameter::SetParameterInfo.

SQL Server Native Client 10.0 implements the OLE DB requirement for bScale in ICommandWithParameter::SetParameterInfo to be set to the fractional seconds' precision for DBTYPE_DBTIMESTAMP.

The sp_columns stored procedure now returns "NO" instead of "NO " for the IS_NULLABLE column.

In SQL Server Native Client 10.0, sp_columns stored procedurenow returns "NO" instead of "NO " for an IS_NULLABLE column.

SQLSetDescRec, SQLBindParameter, and SQLBindCol now perform consistency checking.

Prior to SQL Server Native Client 10.0, setting SQL_DESC_DATA_PTR did not cause a consistency check for any descriptor type in SQLSetDescRec, SQLBindParameter, or SQLBindCol.

SQLCopyDesc now does descriptor consistency checking.

Prior to SQL Server Native Client 10.0, SQLCopyDesc did not do a consistency check when the SQL_DESC_DATA_PTR field was set on a particular record.

SQLGetDescRec no longer does a descriptor consistency check.

Prior to SQL Server Native Client 10.0, SQLGetDescRec performed a descriptor consistency check when the SQL_DESC_DATA_PTR field was set. This was not required by the ODBC specification and in SQL Server Native Client 10.0, this consistency check is no longer performed.

Different error returned when date is out of range.

For the datetime type, a different error number will be returned by SQL Server Native Client 10.0 for an out-of-range date than was returned in earlier versions.

Specifically, SQL Server Native Client 9.0 returned 22007 for all out of range year values in string conversions to datetime, and SQL Server Native Client 10.0 returns 22008 when the date is within the range supported by datetime2 but outside the range supported by datetime or smalldatetime.

datetime value truncates fractional seconds and not round if rounding will change the day.

Prior to SQL Server Native Client 10.0, the client behavior for datetime values sent to the server is to round them to nearest 1/300th of a second. In SQL Server Native Client 10.0, this scenario causes a truncation of fractional seconds if rounding changes the day.

Possible truncation of seconds for datetime value.

An application built with SQL Server 2008 Native Client (or later) that connects to a SQL Server 2005 (or earlier) server will truncate seconds and fractional seconds for time portion of data sent to the server if you bind to a datetime column with a type identifier of DBTYPE_DBTIMESTAMP (OLE DB) or SQL_TIMESTAMP (ODBC) and a scale of 0.

For example:

Input data: 1994-08-21 21:21:36.000

Inserted data: 1994-08-21 21:21:00.000

OLE DB data conversion from DBTYPE_DBTIME to DBTYPE_DATE no longer can cause the day to change.

Prior to SQL Server Native Client 10.0, if the time part of a DBTYPE_DATE was within a half second of midnight, OLE DB conversion code caused the day to change. In SQL Server Native Client 10.0, the day will not change (fractional seconds are truncated and not rounded).

IBCPSession::BCColFmt conversion changes.

In SQL Server Native Client 10.0, when you use IBCPSession::BCOColFmt to convert SQLDATETIME or SQLDATETIME to a string type, a fractional value is exported. For example, when converting type SQLDATETIME to type SQLNVARCHARMAX, earlier versions of SQL Server Native Client returned 

1989-02-01 00:00:00. SQL Server Native Client 10.0 returns 1989-02-01 00:00:00.0000000.

Size of data sent must match length specified in SQL_LEN_DATA_AT_EXEC.

When using SQL_LEN_DATA_AT_EXEC, the size of the data must match the length that you specified with SQL_LEN_DATA_AT_EXEC. You can use SQL_DATA_AT_EXEC but there are potential performance benefits to using SQL_LEN_DATA_AT_EXEC.

Custom applications that use the BCP API can now see a warning.

The BCP API will generate a warning message if data length is greater than the specified length for a field for all types. Previously, this warning was only given for character types, but will not be issued for all types.

Inserting an empty string into a sql_variant bound as a date/time type generates an error.

In SQL Server Native Client 9.0, inserting an empty string into a sql_variant bound as a date/time type did not generate an error. SQL Server Native Client 10.0 correctly generates an error in this situation.

Stricter SQL_C_TYPE _TIMESTAMP and DBTYPE_DBTIMESTAMP parameter validation.

Prior to SQL Server 2008 Native Client, datetime values were rounded to fit the scale of datetime and smalldatetime columns by SQL Server. SQL Server 2008 Native Client (and later) applies the stricter validation rules that are defined in the ODBC core specification for fractional seconds. If a parameter value cannot be converted to the SQL type by using the scale specified or implied by the client binding without truncation of trailing digits, an error is returned.

SQL Server might return different results when a trigger runs.

Changes introduced in SQL Server 2008 might cause an application to have different results returned from a statement that caused a trigger to run when NOCOUNT OFF was in effect. In this situation, your application might generate an error. To resolve this error, set NOCOUNT ON in the trigger or call SQLMoreResults to advance to the next result.

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