NET/MASTER Network Control Language (NCL) Programmer's Guide

Controlling Access to UDBs by NonStop NET/MASTER MS
Working With Files
106160 Tandem Computers Incorporated 12–15
Specifying the Guardian User ID
Your available Guardian user IDs (GUIDs) are assigned to you by User ID
Management Services (UMS). You can determine your current GUID by using the
PROFILE command.
You can control whether a UDB or UDB pair is opened using your current GUID or
the GUID of NonStop NET/MASTER MS when an NCL process uses the FILE OPEN
verb. This is controlled by the SWGUID operand of the UDBCTL OPEN command.
The following example specifies that a UDB is opened using your current GUID when
an NCL process uses the FILE OPEN verb:
UDBCTL OPEN=$DATA.SUBVOL.MYFILE ID=UDBID1 SWGUID=YES
The following example specifies that a UDB pair is opened using your current GUID
when an NCL process uses the FILE OPEN verb:
UDB OPEN=($DATA.SUBVOL.MYFILE1,$DATA.SUBVOL.MYFILE2)
ID=UDBID1 SWGUID=YES
Note The UDBCTL OPEN command does not perform a Guardian OPEN of the file if SWGUID=YES.
Therefore, you do not know whether the file is available until an NCL process attempts to open it using the
FILE OPEN verb. The SHOW UDB command always shows that the UDB or UDB pair is available if
SWGUID=YES (even if the file or files in the UDB pair do not exist).
The following example specifies that a UDB is opened using the GUID of NonStop
NET/MASTER MS when an NCL process uses the FILE OPEN verb:
UDBCTL OPEN=$DATA.SUBVOL.MYFILE ID=UDBID1 SWGUID=NO
The following example specifies that a UDB pair is opened using the GUID of
NonStop NET/MASTER MS when an NCL process uses the FILE OPEN verb:
UDBCTL OPEN=($DATA.SUBVOL.MYFILE1,$DATA.SUBVOL.MYFILE2)
ID=UDBID1 SWGUID=NO
In the preceding two examples, the UDBCTL OPEN command performs a Guardian
OPEN of the file.
Dissociating UDBs From a
UDB Identifier
If a UDB or UDB pair is open, you can dissociate it from its UDB ID by using the
UDBCTL STOP command. After you have done so, NCL cannot access the UDB or
UDB pair until you assign a new identifier to it. The old identifier must not be in use
by any other user or NCL process: otherwise, the dissociation operation fails. The
UDBCTL STOP command does not close the UDB or UDB pair—the UDB or UDB pair
remains open and known to NonStop NET/MASTER MS.
The following example opens a UDB and makes it available to NCL by assigning the
UDB an identifier:
UDBCTL OPEN=$DATA.SUBVOL.MYFILE ID=UDBID1