[RBASE-L] - Re: How to tell if VARBIT column IS NULL

[A. Razzak Memon]

At 10:23 AM 2/12/2009, Lawrence Lustig wrote:

I have a VARBIT column containing images. In my form, I want
to determine whether the column is NULL or contains an image
and adjust my user interface accordingly.

Did you know that you can use the eXtended option of GETPROPERTY
command, related to Table_Column, to achieve your goal?

Syntax:

GETPROPERTY TABLE_COLUMN[TableName->ColumnName] ISNULL varname

Resulting "varname" will return to value of "TRUE" or "FALSE"

. TRUE if NULL
. FALSE if NOT NULL


Here's how:

01. Start R:BASE 7.6 (Build: 7.6.6.30214), or R:BASE Turbo V-8
    (Build: 8.0.20.30214), or R:BASE eXtreme 9.0 (64), or
    R:BASE eXtreme 9.0 (32) Build: 9.0.1.10214.

02. CONNect to appropriate database and open the desired form
    in Form Designer.

    OR

    CONNect to RRBYW15
    Form Name: Contacts
    Table Name: Contact

03. While in Form Designer, use the following GETPROPERTY
    command as "Table | On Row Entry" Custom EEP.

    Form Designer | Main Menu | Tables | Add/Remove Tables...

    Table Settings | Entry/Exit Procedures | On Row Entry:

    Custom EEP:
    -- Based on Table: Contact, Column: ContPhoto (VARBIT)

    GETPROPERTY TABLE_COLUMN[Contact->ContPhoto] ISNULL vValue
    RECALC VARIABLES
    RETURN

04. Now based on the resulting variable "vValue", do what you
    need to do to change the user interface accordingly.

That's all there is to it.

Very Best R:egards,

Razzak.