SAS Federation Server Driver for DB2 :: SAS® Federation Server 4.2: Administrator's Guide, Second Edition

About the SAS Federation Server Driver for DB2

The SAS Federation Server Driver for DB2 (Driver for DB2) enables SAS Federation Server to read and update legacy DB2 tables. In addition, the driver creates DB2 tables that can be accessed by both SAS Federation Server and the DB2 database management system (DBMS). The Driver for DB2 also supports DB2 for z/OS® and DB2 for mid-range systems such as AS/400™, and System i® when using IBM DB2 Connect™ for data access.

The Driver for DB2 supports most of the FedSQL functionality. The driver also supports an application's ability to submit native DB2 SQL statements.

The SAS Federation Server Driver for DB2 is a remote driver, which means that it connects to a server process in order to access data. The process might be running on the same machine as SAS Federation Server, or it might be running on another machine in the network.

Prerequisites

Before configuring SAS Federation Server drivers, you must set environment variables that point to the client libraries required for your data source. See Setting Environment Variables for additional information.

Data Service Connection Options for DB2

Overview

To access data that is hosted on SAS Federation Server, a client must submit a DSN that defines how to connect to the data. DSNs are associated with a data service that provides the foundation for the connection, such as user access control. See Working with Data Services for additional information.

Note: When performing connections through DSNs or connection strings, SAS Federation Server automatically quotes SQL identifiers that do not meet the regular naming convention as defined in the SAS FedSQL Reference Guide.

Connection Options

You can specify one or more connection options when defining a data service and DSN. The Driver for DB2 supports the following connection options for DB2 data sources.

Option	Description
CATALOG	`CATALOG=catalog-identifer;` Specifies an arbitrary identifier for an SQL catalog, which groups logically related schemas. Any identifier is valid (for example, `catalog=DB2`). You must specify a catalog. For the DB2 database, this is a logical catalog name to use as an SQL catalog identifier. Note: SAS Federation Server automatically quotes SQL identifiers that do not meet the regular naming convention as defined in the SAS FedSQL Reference Guide.
DATABASE\|DB	`DATABASE=database-specification;` Specifies the name of the DB2 database, for example, `database=sample, DB=sample`. Note: You must specify a database name.
DRIVER	`DRIVER=DB2;` Identifies the DB2 data source to which you want to connect. Note: You must specify the driver.

Advanced Connection Options

SAS Federation Server Driver for DB2 supports the following advanced connection options for DB2 data sources.

Option

Description

CLIENT ENCODING

CLIENT_ENCODING=encoding-value

Used to specify the encoding of the DB2CODEPAGE to the DB2 driver. When using this option, you must also set the DB2CODEPAGE environment variable on the client.

When the encoding of the DB2 client layer that is stored in DBCODEPAGE, differs from the encoding value of the DB2 operating system value, which is generally the SAS session encoding value, the DB2 client layer attempts to convert incoming data to the DB2 encoding value that is stored in DB2CODEPAGE. To prevent the client layer from converting data incorrectly, you must first determine the correct value for DB2CODEPAGE and then set the CLIENT_ENCODING= option to match the corresponding encoding value in DB2CODEPAGE.

For example, suppose you are storing Japanese characters in a DB2 database and the client machine where the DB2 driver is executing is a Windows machine running CP1252 encoding. When the application tries to extract the data into SAS Federation Server, the DB2 client layer attempts to convert these Japanese characters into Latin1 representation, which does not contain Japanese characters. As a result, a garbage character appears to indicate a failure in transcoding.

To resolve this situation, you must first set the DB2CODEPAGE environment variable value to 1208 (the IBM code page value that matches UTF-8 encoding) to specify that the DB2 client layer send the data to the application in UTF-8 instead of converting it into Latin1. In addition, you must specify the corresponding encoding value of DB2CODEPAGE because the SAS Federation Server Driver for DB2 cannot derive this information from a DB2 session. For this particular case, set the CLIENT_ENCODING= option to the UTF-8 to match the DB2CODEPAGE value (1208) in order to specify the DB2CODEPAGE value to the DB2 driver.

However, changing the value of DB2CODEPAGE affects all applications that run on that machine. You should reset the value to the usual DB2CODEPAGE value, which was derived when the database was created.

Note: Setting the DB2CODEPAGE value or the CLIENT_ENCODING= value incorrectly can cause unpredictable results. You should set these values only when a situation such as the example above occurs.

CT_PRESERVE

CT_PRESERVE=STRICT
                                       | SAFE | FORCE | FORCE_COL_SIZE

Allows users to control how data types are mapped. Note that data type mapping is disabled when CT_PRESERVE is set to STRICT. If the requested type does not exist on the target database, an error is returned. The options are as follows:

STRICT The requested type must exist in the target database. No type promotion occurs. If the type does not exist, an error is returned.
SAFE Target data types are upscaled only if they do not result in a loss of precision or scale. When character encodings are changed, the new column size is recalculated to ensure all characters can be stored in the new encoding.
FORCE This is the default for all drivers. The best corresponding target data type is chosen, even if it could potentially result in a loss of precision or scale. When character encodings are changed, the new column size is recalculated to ensure all characters can be stored in the new encoding.
FORCE_COL_SIZE This option is the same as FORCE, except that the column size for the new encoding is the same as the original encoding. This option can be used to avoid column size creep. However, the resulting column might be too large or too small for the target data.

DEFAULT_ATTR

DEFAULT_ATTR=(attr=value;...)

Used to specify connection handle or statement handle attributes supported for initial connect-time configuration, where attr=value corresponds to any of the following options:

CURSORS=n- Connection handle option. This option controls the driver’s use of client side result set cursors. The possible values are 0, 1 or 2.

0	Causes the driver to use client-side static cursor emulation if a scrollable cursor is requested but the database server cannot provide one.
1	Causes the driver to always use client-side static cursor emulation if a scrollable cursor is requested. The database server’s native cursor is not used.
2	(Default) Causes the driver to never use client-side static cursor emulation if a scrollable cursor is requested. The database server’s native cursor is used if available. Otherwise, the cursor will be forward-only.

Example: DEFAULT_ATTR=(CURSORS=2)

USE_EVP=n - Statement handle option. This option optimizes the driver for large result sets. The possible values are 0 (OFF) or 1 (ON), which is the default. Example: DEFAULT_ATTR=(USE_EVP=0)
XCODE_WARN=n - Statement handle option. Used to warn on character transcoding errors that occur during row input or output operations. Possible values are 0 (returns an error), 1 (returns a warning), or 2 (ignore transaction errors). 0 is the default. Example: DEFAULT_ATTR=(XCODE_WARN=1)

DRIVER TRACE

DRIVER_TRACE=’API
                                       | SQL | ALL’;

Requests tracing information, which logs transaction records to an external file that can be used for debugging purposes. The SAS Federation Server driver writes a record of each command that is sent to the database to the trace log based on the specified tracing level, which determines the type of tracing information. The tracing levels are as follows:

ALL Activates all trace levels.
API Specifies that API method calls be sent to the trace log. This option is most useful if you are having a problem and need to send a trace log to Technical Support for troubleshooting.
DRIVER Specifies that driver-specific information be sent to the trace log.
SQL Specifies that SQL statements that are sent to the database management system (DBMS) be sent to the trace log. Tracing information is DBMS specific, but most SAS Federation Server drivers log SQL statements such as SELECT and COMMIT.

Default: Tracing is not activated.

Note: If you activate tracing, you must also specify the location of the trace log with DRIVER_TRACEFILE=. Note that DRIVER_TRACEFILE= is resolved against the TRACEFILEPATH set in ALTER SERVER. TRACEFILEPATH is relative to the server's content root location.

(Optional) You can control trace log formatting with DRIVER_TRACEOPTIONS=.

Interaction: You can specify one trace level, or you can concatenate more than one by including the | (OR) symbol. For example, driver_trace='api|sql' generates tracing information for API calls and SQL statements.

DRIVER TRACE FILE

DRIVER_TRACEFILE=’filename’;

Used to specify the name of the text file for the trace log. Include the filename and extension in single or double quotation marks. For example: driver_tracefile='\mytrace.log'

Default: The default TRACEFILE location applies to a relative filename, and it is placed relative to TRACEFILEPATH.

Requirement: DRIVER_TRACEFILE is required when activating tracing using DRIVER_TRACE.

Interaction: (Optional) You can control trace log formatting with DRIVER_TRACEOPTIONS=.

DRIVER TRACE OPTIONS

DRIVER_TRACEOPTIONS=APPEND
                                       | THREADSTAMP | TIMESTAMP;

Specifies options in order to control formatting and other properties for the trace log:

APPEND Adds trace information to the end of an existing trace log. The contents of the file are not overwritten.
THREADSTAMP Prepends each line of the trace log with a thread identification.
TIMESTAMP Prepends each line of the trace log with a time stamp.

Default: The trace log is overwritten with no thread identification or time stamp.

PASSWORD

PWD=password

Specifies the password for DB2.

USER ID

UID=user-id;

Specifies the DB2 login user ID.

DB2 Wire Protocol Driver Usage Notes

SAS Federation Server provides a number of wire protocol ODBC drivers that communicate directly with a database server, without having to communicate through a client library. When you configure the ODBC drivers on Windows or UNIX, you have the opportunity to set certain options. SAS products run best when these options are selected. Some, but not all, are selected by default.

Windows	The options are located on the Advanced or Performance tabs in the ODBC Administrator.
UNIX	The options are available when configuring data sources using the `dfdbconf` tool. Values can also be set by editing the `odbc.ini` file in which their data sources are defined.

Note: The behavior of a DSN using a wire protocol driver with the catalog option selected, returns only the schemas that have associated tables or views. To list all existing schemas, create a DSN without the catalog option selected.

When configuring an ODBC DSN using the DB2 Wire Protocol driver, set the following advanced options:

Application Using Threads