User FAQs

This topic collection concentrates on describing iSeries™ support for distributed relational databases in a network of iSeries servers (a like environment).

Many distributed relational database implementations exist in a network of different DRDA-supporting platforms. This topic collection provides a list of tips and techniques you might need to consider when using the iSeries server in an unlike DRDA^® environment.

This topic collection describes some conditions you need to consider when working with another specific IBM^® product. It is not intended to be a comprehensive list. Many problems or conditions like the ones described here depend significantly on your application. You can get more information about the differences between the various IBM platforms from the IBM SQL Reference Volume 2, SC26-8416, or the DRDA Application Programming Guide, SC26-4773.

• Connect to a distributed relational database
  When you connect from a non-iSeries application requester (AR) to a DB2 Universal Database™ for iSeries application server (AS), columns tagged with CCSID 65535 are not converted. If the files that contain these columns do not contain any columns that have a CCSID explicitly identified, the CCSID of all character columns can be changed to another CCSID value. To change the CCSID, use the Change Physical File (CHGPF) command. If you have logical files built over the physical file, follow the directions given in the recovery topic of the error message (CPD322D) that you get.
• iSeries system value QCCSID
  The iSeries server is shipped with a QCCSID system value set to 65535.
• CCSID conversion considerations for DB2 Universal Database for z/OS and DB2 Universal Database server for VM database managers
  One of the differences between a DB2 Universal Database™ for iSeries and other DB2^® databases is that the iSeries system supports a larger set of CCSIDs. This can lead to errors when the other database managers attempt to perform character conversion on the data (SQLCODE –332 and SQLSTATE 57017).
• Why am I getting a SQL5048N message when I attempt to connect from DB2 Universal Database for Linux, UNIX and Windows?
  The definition of message SQL5048N states that the release level of the database client is not supported by the release level of the database server. However, the message can sometimes be misleading.
• Do iSeries files have to be journaled?
  Journaling is not required if the client application is using an isolation level of no-commit (NC) or uncommitted read (UR), and if the DB2^® UDB SQL function determines that the query data can be blocked. In that case commitment control is not enabled, which makes journaling unnecessary.
• When will query data be blocked for better performance?
  The query data will be blocked if none of these conditions are true.
• How do you interpret an SQLCODE and the associated tokens reported in a DBM SQL0969N error message?
  The client support used with DB2 Universal Database™ for Linux^®, UNIX^® and Windows^® returns message SQL0969N when reporting host SQLCODEs and tokens for which it has no equivalent code.
• How can the host variable type in WHERE clauses affect performance?
  One potential source of performance degradation on an iSeries server is the client's use in a C program of a floating point variable for a comparison in the WHERE clause of a SELECT statement.
• Can I use a library list for resolving unqualified table and view names?
  The iSeries server supports a limited capability to use the operating system naming option when accessing DB2 Universal Database™ for iSeries data from a non-iSeries DRDA client program such as those that use the DB2 Universal Database™ for Linux^®, UNIX^® and Windows^® product.
• Can a user of DB2 Universal Database for Linux, UNIX and Windows specify that the NLSS sort sequence table of the DRDA job on the iSeries server be used instead of the usual EBCDIC sequence?
  The iSeries server recognizes a generic bind option that allows one who prepares a program to be run from DB2 Universal Database™ for Linux^®, UNIX^® and Windows^® or any other client that supports generic bind options to request that the iSeries server use the NLSS sort sequence associated with the server job in which the client's request is run.
• Why are no rows returned when I perform a query?
  One potential cause of this problem is a failure to add an entry for the iSeries server in the DB2 Universal Database™ for Linux^®, UNIX^® and Windows^® Database Communication Services Directory.
• What level of DB2 Universal Database for Linux, UNIX, Windows is required to interact with DB2 Universal Database for iSeries?
  These Fix Packs are required for interaction.
• How can I get scrollable cursor support enabled from DB2 Universal Database for Linux, Unix and Windows Version 8 to the iSeries?
  You must be using FixPak 4 or later on the client.
• Other tips for interoperating in unlike environments
  This topic collection provides additional information for using DB2 Universal Database™ for iSeries with DB2 Universal Database™ for Linux^®, UNIX^® and Windows^®. These tips were developed from experiences testing with the products on an OS/2^® platform, but it is believed that they apply to all environments to which they have been ported.