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DF_FILE_FETCH_ALL_COLUMNS

Indicates whether selective column fetching is on or off for the table.

Level

Table

Supported by

The DataFlex SQL Drivers (SQL Server, DB2, and ODBC)

Type

Boolean, temporary

Access

Read / Write

Values

  • True
  • False

Syntax

Use cli.pkg
Get_Attribute DF_FILE_FETCH_ALL_COLUMNS of {tableNumber} to {BooleanVariable}

Set_Attribute DF_FILE_FETCH_ALL_COLUMNS of {tableNumber} to {True|False}

Remarks

This table attribute indicates whether selective column fetching is ON or OFF for the table. When a table is opened, the attribute is automatically set to true (all columns will be fetched after opening).

Selective Column Fetching (SCF) offers a way to programmatically influence the number of columns that are fetched from the back-end. This feature is especially useful when looping through records. It is supported by the DataFlex SQL Drivers. Limiting the number of columns that are fetched reduces the amount of data that is sent from the database server to the client, thus improving performance.

There are two levels in which SCF can be controlled: - It can be switched ON or OFF at the table level using the DF_FILE_FETCH_ALL_COLUMNS attribute. - It can be switched ON or OFF for individual columns using the DF_FIELD_FETCH_STATE attribute.

This attribute can only be set outside of a Structure_Start ... Structure_End operation.

For more information on using this attribute, see the Selective Column Fetching section.