Block (ODBC, OLE DB, and Oracle)

Description

For those interfaces that support it, Block specifies the cursor blocking factor when connecting to a database. The blocking factor determines the number of rows that a report can fetch from the database at one time.

Using the Block parameter can improve performance when accessing a database in InfoMaker.

Applies to

ODBC (if driver and back-end DBMS support this feature)
OLE DB
O84 Oracle 8.x and Oracle8i
O90 Oracle9i
O10 Oracle 10g

Syntax

Block = blocking_factor

Parameter	Description
blocking_factor	The number of rows you want the report to fetch from the database at one time. The blocking factor can be a number from 1 to 1000, inclusive. To turn off block fetching, set Block to 1.

Parameter

Description

blocking_factor

The number of rows you want the report to fetch from the database at one time. The blocking factor can be a number from 1 to 1000, inclusive.

To turn off block fetching, set Block to 1.

Default

The default value for the Block parameter depends on the DBMS you are accessing, as summarized in the following table:

DBMS	Block default value
ODBC	For most reports, the Block default value is the following, up to a maximum of 32K per column: Block = 1000 If you specified that the report should retrieve only as many rows as needed from the database (Retrieve.AsNeeded property), the Block default value is the following, up to a maximum of 32K per column: Block = 100
OLE DB	InfoMaker sets the blocking factor to 1
Oracle	InfoMaker sets the blocking factor to 300 rows.

DBMS

Block default value

ODBC

For most reports, the Block default value is the following, up to a maximum of 32K per column:

Block = 1000

If you specified that the report should retrieve only as many rows as needed from the database (Retrieve.AsNeeded property), the Block default value is the following, up to a maximum of 32K per column:

Block = 100

OLE DB

InfoMaker sets the blocking factor to 1

Oracle

InfoMaker sets the blocking factor to 300 rows.

Using the default blocking factor You should not have to set a non-default value for Block. In most cases, the default blocking factor used by InfoMaker should meet your needs.

Usage

Requirements for ODBC data sources To use the Block parameter with an ODBC data source, your ODBC driver must:

Be ODBC Version 2.0 compliant or higher, and
Support the SQLExtendedFetch API call

The Adaptive Server® Anywhere ODBC driver that comes with InfoMaker meets both of these requirements.

For information about whether your ODBC driver meets these requirements, see the documentation that comes with your driver.

Determining the Block value for ODBC data sources InfoMaker searches the following in this order to determine the Block value for ODBC data sources:

The section for your database profile in the registry or the value of the Transaction object property (in an application)
The section for your ODBC driver in the PBODB105 initialization file

If InfoMaker does not find a Block value in these locations, it uses the default Block value for the DBMS you are accessing.

Turning off block fetching To turn off block fetching for an ODBC data source or Oracle database, set the Block parameter to 1.

Examples

Example 1

To set the blocking factor for reports to 50 rows:

Database profile Type 50 in the Retrieve Blocking Factor box on the Transaction tab in the Database Profile Setup dialog box.