Configuring the Client on Windows › Setting Advanced Data Source Options › Default Connection Attributes

Default Connection Attributes

Access Mode

Specifies the default setting for the access mode connection attribute, which is defined by both ODBC and JDBC. An application can use the ODBC or JDBC interfaces to set and query this attribute at run-time. Options are:

• READ WRITE—Allows applications to read and update the database.
• READ ONLY—Allows applications to read the database. This option is recommended, unless you intend to update data in the CA IDMS database. This option can be set and queried by the application using the SQLSetConnectOption and SQLGetConnectOption functions.
• <SYSTEM DEFAULT>—Indicates that the System-level setting for this option should be used.

If no specification is made at both the Data Source and the System level, then a runtime default of "READ WRITE" is used.

Transaction Isolation

Specifies the degree to which your transactions impact, and are impacted by, other users accessing the same data for the ODBC driver. Choose one of the following:

• READ COMMITTED—Prevents access to data updated by another user, before it has been committed. This corresponds to the CURSOR STABILITY option of the SQL SET TRANSACTION statement, and is the default setting.
• READ UNCOMMITTED—Permits only retrieval operations to be executed by the user; update requests are rejected. This option can only be selected in conjunction with a Read Only Access Mode, and corresponds to the TRANSIENT READ option on the SET TRANSACTION statement.
• <SYSTEM DEFAULT>—Indicates that the System-level setting for this option should be used.

If no specification is made at both the Data Source and the System level, then a runtime default of "READ COMMITTED" is used.

This option can be set and queried by the application using the SQLSetConnectOption and SQLGetConnectOption functions.

Note: For more information about the SET TRANSACTION statement, see the CA IDMS Database SQL Option Reference Guide.

Commit Behavior

Specifies the way in which COMMIT operations affect cursors in the ODBC and JDBC drivers. Choose one of the following options:

• CLOSE AND DELETE CURSORS—Forces the application to prepare and execute the next statement.
• CLOSE CURSORS—Allows applications to execute a statement without calling prepare again. This is the default setting.
• PRESERVE CURSORS—Maintains cursors in the same position as before the Commit operation, allowing applications to execute or fetch without preparing the statement again.
• <SYSTEM DEFAULT>—Indicates that the System-level setting for this option should be used.

If no specification is made at either the Data Source or the System level, then a runtime default of "CLOSE CURSORS" is used.

This is a CA IDMS Server extension allowing you to optimize ODBC usage by different applications. An ODBC application can use the SQLGetInfo function to query this setting. A JDBC application can use the GetResultSetHoldability method.

Invalid Decimal Action

Specifies how the CA IDMS ODBC and JDBC drivers handle invalid packed or zoned decimal data in a result set column. This option is useful when accessing network databases, where records may be redefined so that decimal fields can contain non-numeric data. Options are:

• RETURN ERROR—The drivers return an error to the application. The ODBC driver returns SQL_ERROR to the application, which can use the SQLError function to retrieve the associated error message. The JDBC driver throws a SQLException containing the error message. No value is returned in the output buffer provided by the application.
• RETURN NULL—The drivers attempt to return NULL for the column value. The ODBC driver does this by setting the length/indicator value to SQL_NULL_DATA. It returns an error if the pointer to the length/value indicator supplied by the application is 0. The JDBC driver returns either 0 or null as specified by the ResultSet getter method, and returns true for the ResultSet wasNull method. Note that the drivers attempt to return NULL even if the column in the result set is defined as NOT NULL.
• RETURN 0—The driver always returns 0. This can be useful when the application does not provide the length/indicator value for a column that is NOT NULL.
• IGNORE—The value returned to the application is undefined. This option is provided for compatibility with previous versions of the ODBC driver. It is not supported by the JDBC driver.
• <SYSTEM DEFAULT>—Indicates that the System-level setting for this option should be used.

If not specified for a data source or as the system default, the default is RETURN ERROR. The ODBC driver prints a warning message to the log when tracing is enabled, no matter which option is selected.

Suspend Strategy

Specifies how the CA IDMS ODBC and JDBC drivers use SQL SUSPEND and COMMIT requests to optimize task resource usage on the CA IDMS system. These strategies replace detailed suspend and commit options that were set in the Windows registry directly for prior releases. The strategies are:

• INTERACTIVE—Select this setting when the Data Source is to be used with an interactive ("fat client") application, such as Visual Express or Visual DBA. The drivers SUSPEND after each COMMIT.
• SERVICE—Select this setting when the Data Source is to be used as a service, such as an applications that uses a pooled connection in an application server (WebSphere, Weblogic, etc). The drivers SUSPEND when the connection is returned to the idle pool.
• BATCH—Select this setting when the Data Source is to be used by a batch-type application, where pseudo-conversational processing is not used. The drivers do not SUSPEND at all.
• CUSTOM—Select this setting when you need to specify detailed suspend and commit options in the registry. This setting should only be used by advanced users, or under the direction of CA Technical Support, and requires manual editing of the Windows Registry.
• <SYSTEM DEFAULT>—Indicates that the System-level setting for this option should be used.

If no specification is made at either the Data Source or the System level, then a runtime default of "CUSTOM" is used. Note that if no detailed options have been specified this is equivalent to "INTERACTIVE." Refer to Chapter 3, "Setting Up Your CA IDMS System", and the "Windows Registry Information" Appendix for information about using the detailed options.

Fetch Row Count

Specifies the number of database rows to be fetched in a single database request. CA IDMS supports a BULK FETCH feature than can improve performance by fetching multiple rows with a single database request. This option specifies the default value for the number of rows that the driver attempts to fetch. An application can use ODBC and JDBC interfaces to set and query this value at run-time. Valid values are 0 to 30000. The drivers use a smaller value if the value specified would require a buffer larger than the Fetch Buffer Size.

When the value is 0 for a data source, the drivers use the system default, if any. If the system default is also 0, the drivers compute the number of rows that fit in the fetch buffer.

The default is usually appropriate for most applications.

Fetch Buffer Size

Specifies the maximum size of the fetch buffer. The drivers adjust the number of rows to fit in the buffer if necessary. Valid values are 0 to 1048576, although the maximum when using CCI is 30000.

When the value is 0 for a data source, the drivers use the system default, if any. When the system default is also 0 the drivers use 30000 for the CCI communications protocol and 64000 for the IDMS communications protocol.

The default is usually appropriate for most applications.