Release manifest for MDAC 2.1 Service Pack 2 (2.1.2.4202.3)

Release version number

MDAC 2.1 SP2 (2.1.2.4202.3) (GA), July 1999

Release function

MDAC 2.1 SP2 (2.1.2.4202.3) includes Quick Fix Engineering (QFE) fixes and selective fixes that customers have requested.

Release ship vehicle

To download MDAC 2.1 SP2 (2.1.2.4202.3), visit the following MSDN Web site:

Localization information

MDAC 2.1 SP2 (2.1.2.4202.3) (GA) is available in US English.

New features

MDAC 2.1 SP2 (2.1.2.4202.3) (GA) is not a new feature release.

Known issue with MDAC 2.1.2.4202.3 (GA)

This release has a known issue with the Online Database Connectivity (ODBC) Jet driver in multithreaded environments. When any multithreaded environment or stress environment such as Microsoft Internet Information Services (IIS) is running, we recommend that you do not use ODBC because of issues with threading in the driver and in the Jet engine. In this situation, we recommend that you work with the OLE DB provider for Jet.

Significant fixes for MDAC 2.1 SP2 (2.1.2.4202.3) (GA)

The following significant fixes were implemented in this MDAC release:

General fixes

• This MDAC release contains a fix in the Microsoft Visual FoxPro driver. This fix is not included in the release for Microsoft Office 2000.
• This MDAC release contains fixes that are included in the Microsoft SQL Server driver and in the provider that is included in SQL Server 7.0 Service Pack 1 (SP1).
• Many alignment faults in the Alpha (AXP) builds of MDAC 2.1.2.4202.3 (GA) have been detected and fixed.
• This MDAC release contains a fix for an error that occurs in Microsoft Visual C++ 6.0. In Visual C++ 6.0, the Microsoft Foundation Classes (MFC) AppWizard application generates code. When you run this code, you may receive the following error message:
  Failed to open recordset.
  This problem occurs because of an error in the way that rows are fetched.

ADO

• Active Server Pages (ASP) scripts return empty recordsets under stress.
  
  When ActiveX Data Objects (ADO) runs in an IIS environment under heavy stress, ADO may start to return empty recordsets to requests from the database. This is not a common problem because the problem rarely surfaces before four to 15 days have passed. The problem occurs because of memory fragmentation. When a certain threshold is reached, there is not sufficient memory to allocate for the row buffers. At this point, empty recordsets start to return.
• Using multiple recordsets on a single command object may cause an application error.
  
  When an application that uses multiple recordsets on a single command object runs in a stress environment such as IIS, an application error may occur. This problem involves the persistence of the parameters collection on the command object and the time that the parameters collection should be persisted before the parameters collection is reused.
  
  For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
  197449 Problems reusing ADO command object on multiple recordsets
  
  

RDS

• Remote Data Services (RDS) role impersonation does not behave as expected.
  
  When Remote Data Services (RDS) is used to call a local or remote Component Object Model (COM) server, the server only recognizes the first caller to the object. If different clients make later calls to the object, the server only recognizes them as the initial caller.
  
  
  

Jet ODBC driver

• A problem occurs when you try to delete rows.
  
  If a row is deleted from a database in an environment that uses the Jet ODBC driver, the Jet ODBC driver does not leave the application on the expected row. The application may be returned to the beginning of the table or may be moved to the next row. This behavior depends on the cursor options that are used.
• The CREATE_DBV4 keyword has been added for the Jet ODBC driver.
  
  Version 4.0 of the Jet ODBC driver is included with MDAC 2.1. By default, with version 4.0 of the Jet ODBC driver, a version 4.0 database is created when you create a new database by using the CREATE_DB keyword. This causes problems for applications that expect a version 3.0 database to be created. Version 3.0 databases are created when you use version 3.5 of the Jet ODBC driver. Version 3.5 of the Jet ODBC driver is included with MDAC 2.0. With MDAC 2.1 SP2, developers can explicitly use the CREATE_DBV4 keyword to make sure that databases are created with the correct version.

Jet

• A General Protection Fault (GPF) occurs when Jet parses a CHECK condition in a subquery, and the subquery contains a JOIN operator that joins the subquery to the copybuffer.
  
  The following code illustrates this problem:

  ALTER TABLE Orders
    ADD CONSTRAINT ValidCustId CHECK (custid = ANY (SELECT custid FROM
    EmptyCustomers AS c WHERE c.custid = Orders.custid))

  The query must contain the subquery that holds the JOIN operator.
• An inconsistent result set is obtained when scrollable cursors and updateable cursors are passed to the index decimal column that is combined with a JOIN statement.
  
  The result set is not consistent when scrollable cursors or updateable cursors are passed on a JOIN statement of an indexed decimal column.
• Backward compatibility with stored queries is broken in Jet 4.0. The stored queries behave as follows:
  
  • The {call QueryStar} stored query uses the LIKE operator with the asterisk character (*) and returns X rows.
  • The SELECT * FROM Table WHERE LIKE "M*" stored query runs as an SQL statement. The stored query returns zero rows because it uses ODBC behavior.
  • The {call QueryPerc} stored query uses the LIKE operator with the percent sign (%) and returns zero rows.
  • The SELECT * FROM Table WHERE LIKE "M%" stored query runs as an SQL statement and returns
    X rows.
• GUID data type conversion corrupts data.
  
  When you insert data from one table in another table, data corruption may occur when all the following conditions are true:
  
  • You have two remote links, Table1 and Table2, to two Microsoft SQL Server tables.
  • Each table has a column type GUID.
  • The values that are inserted in Table2 are different from the values that already exist in Table2.
• A #Deleted error occurs when you link to an Oracle table that contains numeric values.
  
  When an Oracle table is linked to Access, decimal values are incorrectly scaled, and data truncation occurs.
• Access 2000 cannot open attached AS/400 tables.
  
  When you try to open an attached AS/400 table in Access datasheet view, you receive the following error message:
  Microsoft Access cannot open this table in datasheet view

File List for MDAC 2.1.2.4202.3 (GA)