NullSupported (Property)

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NullSupported (Property)

In french: NullSupporté

Available only with these kinds of connection

The NullSupported property is used to manage the NULL value in HFSQL data files.

This property is used to:

Determine how the NULL value is handled for a data file described in the data model editor.
Define that the NULL value will be handled when a data file is described through programming.

Remark: If the data file and the item support NULL values (NullAllowed property), the Null property can be used to assign NULL to the item for the current record.

Example

// Define the management mode of the NULL value in the Customer data file
Customer.NullSupported = True

Syntax

Determining if the data supports the NULL value Hide the details

<Result> = <Data file>.NullSupported

<Result>: Boolean

True if the file supports the NULL value,
False otherwise.

<Data file>: Character string

Logical name of the data file used. This name was defined in the data model editor or with the File Description type.

Defining how the NULL value will be handled Hide the details

<Data file>.NullSupported = <Management mode>

<Data file>: Character string

Logical name of the data file used. This name was defined by the File Description type.

<Management mode>: Boolean

True to manage the NULL value,
False otherwise.

Remarks

Special case: View and query

When used on a view or query, the NullSupported property returns True if at least one of the source files supports the NULL value.

Error cases

Write access to the Null property fails if the NullSupported property is set to False.

The error 70409 ("You have called HModify. The <XXXX> file does not support the access to the Null property. The management of the Null value must be enabled in the file description.") occurs if the following conditions are fullfilled:

an item found in a query or in a view is set to NULL,
this item comes from a file that does not support the NULL value
HModify is used on the query or on the view.