DescribeOutputLevel CLI/ODBC and IBM data server driver configuration keyword
Sets the level of output column describe information that is requested by the CLI driver during prepare or describe requests.
- db2cli.ini keyword syntax:
- DescribeOutputLevel = 0 | 1 | 2 | 3
- IBM® data server driver configuration file (db2dsdriver.cfg) syntax:
- <parameter name="DescribeOutputLevel" value="0 | 1 | 2 | 3"/>
Attention: The IBM data server
driver configuration
file (db2dsdriver.cfg) syntax is available in Db2 11.5.4 and later.
- Default setting:
- Request the describe information that is listed in level 2 of Table 1.
- Equivalent connection attribute:
- SQL_ATTR_DESCRIBE_OUTPUT_LEVEL
- Usage notes:
-
This keyword controls the amount of information the CLI driver requests on a prepare or describe request. By default, when the server receives a describe request, it returns the information that is contained in level 2 of Table 1 for the result set columns. An application, however, might not need all of this information or might need additional information. Setting the DescribeOutputLevel keyword to a level that suits the needs of the client application might improve performance because the describe data that are transferred between the client and server is limited to the minimum amount that the application requires. If the DescribeOutputLevel setting is set too low, it can affect the functionality of the application (depending on the application's requirements). The CLI functions to retrieve the describe information might not fail in this case, but the information that returned might be incomplete. Supported settings for DescribeOutputLevel includes following values:
- 0 - no describe information is returned to the client application
- 1 - describe information that is categorized in level 1 (see Table 1) is returned to the client application
- 2 - (default) describe information that is categorized in level 2 (see Table 1) is returned to the client application
- 3 - describe information that is categorized in level 3 (see Table 1) is returned to the client application
The following table lists the fields that form the describe information that the server returns when it receives a prepare or describe request. These fields are grouped into levels, and the DescribeOutputLevel db2cli.ini configuration keyword controls which levels of describe information the CLI driver requests.
Note:- The default behavior allows the CLI driver to promote the describe level to 3 if the application asks for describe information that was not initially retrieved with the default level 2. The promotions of a describe level value might result in two network flows to the server. If an application uses the DescribeOutputLevel keyword to explicitly set a describe level, then no promotion of a describe level takes place. Therefore, if the keyword is used to set the describe level to 2, the CLI driver does not promote a describe level to 3 even if the application asks for extended information.
| Level 1 | Level 2 | Level 3 |
|---|---|---|
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