Variables, Substitution, and Assignment › Vartable Facility

Vartable Facility

A vartable is an in-storage table with the following attributes:

• A name, assigned when the table is created, and used to refer to the table.
• A scope, which can be one of:

  PROCESS

  (Default) Indicates that the table is only visible to the NCL PROCESS that allocated it. It is automatically freed when the process terminates, if not explicitly freed beforehand. Table names must be unique within a process, but different processes can operate using different tables with the same name.

  REGION

  Indicates that the table is visible to all NCL processes in a processing region. For a signed-on user, this means all NCL processes running in either NCL window, under the User Services menu, MAI script procedures, and so on. The table is automatically freed when the region terminates (for example, when the user signs off), if not explicitly freed beforehand. Table names must be unique within the region, but different regions can use different tables of the same name.

  SYSTEM

  Indicates that the table is visible to all NCL processes in this address space. The table is automatically deleted when your product terminates, if not explicitly freed sometime beforehand.

  SYSTEM scope replaced GLOBAL in an earlier version but the use of GLOBAL is supported.

  AOM

  Indicates that the statement refers to a mirrored vartable if AOM has started.

• A key length, from 1 to 256 characters long. Each table can have a different key length.
• Zero or more entries, consisting of:
  • A key. Every entry must have a unique key, which can be numeric.
  • Up to 16 items of data, or an unlimited number of data items if DATA=MAPPED is specified. Each item can be from 0 (null, not present) to 256 characters long. The data value is null if no data is provided for an item when an entry is added.
  • A counter field, which is initialized to 0 when an entry is created, and can be reset to any value, or adjusted by any amount, on update calls.
  • A user correlator field. This field is maintained by the system, and can be used to provide update synchronization for tables shared between NCL processes (that is, for tables with SCOPE= REGION or SYSTEM only).

The entries in a table are maintained in ascending key field value order. The retrieval option of &VARTABLE allows sequential retrieval in ascending or descending order.