This document covers the following topics:
Symbol Tables and Symbols in the Concepts and Facilities documentation
A symbol table is used to maintain common parameter definitions that apply to all jobs of a network. A symbol table contains a list of defined symbols with values that can be used for parameter substitution during JCL generation.
You can maintain symbol tables by using either Entire Operations maintenance functions or user-written programs, user exits and application programming interfaces (APIs) supplied by Entire Operations. This allows modification of symbol tables and symbol values during job network processing.
Symbol tables are associated with owners. Each owner can have several symbol tables. You can only maintain the symbol tables that belong to your owner.
The symbol table to be referenced by a job and/or network must be specified in the job or network master definition or in the active queue for a single job run. Exceptions are global symbol tables.
Each network activation initiates its own active copy (active symbol table) of the linked symbol table(s). This allows you to schedule networks with different parameter sets, even a long time in advance. Any occurrence of a symbol name in the JCL or in a script is replaced by its current value.
This section covers the following topics:
A master symbol table defined by the owner SYSDBA is considered a
global symbol table because it can be references by multiple jobs and networks
without explicit specifications in the job and network definitions. A global
symbol table with the name A is supplied for the owner SYSDBA by
default. It can be accessed and referenced by all owners.
All other owners can also define a global symbol table with the name
A for their networks. Their global symbol table A
then takes priority over the global symbol table A defined by
SYSDBA. See also Symbol
Table Types and Symbol Search Order.
During job or network activation, an active copy of each symbol table used by a job or network is created by copying it to the active database. This is then called the active symbol table. Symbols to be replaced are taken from the active symbol table. This enables different values of the same symbols to be generated for different runs of the network or job.
To identify an active symbol table uniquely, both the network name and run number are required.
For scheduled network activation, you can select the time to activate the symbol table in the network definition. This can be either of the following:
Directly after the schedule extraction; this allows enough time for manual symbol replacement.
During the network activation. In this case, however, manual symbol replacement is not possible.
Active symbols are maintained analogously to master symbols. Therefore, only the maintenance of master symbol tables and symbols is described in the section Adding and Maintaining Symbol Tables.
Note:
All modifications of active symbols apply to the current run only.
The symbol table name with the prefix =EOR= is reserved
for internal control purposes. This prefix must not be used for any
user-defined table names.
You can maintain several versions of a master symbol table as described in Symbol Table Versioning in the Concepts and Facilities documentation. Exceptions are global symbol tables for which versioning is not allowed.
If you have several symbol table versions, you can define a validity period for each version. See the section Maintaining the Usage of Symbol Table Versions.
A symbol is a variable definition that contains the format, prompting type, prompting text (optional) and the value(s) of the symbol.
Symbols can be defined by using Entire Operations maintenance functions, or they can be set and modified by any program, which invokes the Entire Operations symbol API NOPUSY6N (see the section API Routines) to set, reset, or modify a symbol.
For detailed information on defining symbols in JCL (including text objects) or Natural macro sources, see Editing Master JCL and Natural Sources and Inserting Text Objects into the JCL in the section Job Maintenance.
This section covers the following topics:
A master symbol contained in a global symbol table is considered a global symbol because it can be used by multiple jobs and networks without extra definitions for each job and/or network that references the symbol. See also Global Symbol Tables..
Predefined symbols provided by Entire Operations are described in the section Predefined Symbols.
Symbols are usually replaced during the activation of a job network or job, that is, during the loading of the active JCL to the active database. In certain cases, symbol replacement can even be used in file names, messages texts, etc.
A symbol to be replaced is identified by an escape character defined in the Entire Operations default and network settings, or used as a prefix in JCL and Natural macro sources. You specify the symbols in JCL or macro sources as described in Defining Escape Characters.
If a symbol is not found in the symbol table specified for a job or network, the symbol is searched for in the global symbol table(s). The first match is used to replace the symbol. A symbol is not replaced if it cannot be found in any table; an appropriate error message is then issued instead. See also Symbol Table Types and Symbol Search Order.
For further information, see the separate chapter Symbol Replacement.
You can define whether a symbol is prompted for symbol modification during or before job network activation.
During a manual network or job activation, the prompting is performed immediately. See the section Symbol Prompting during Network or Job Activation.
For scheduled (automatic) activations, prompting requests are sent to a mailbox linked to the network. The network activation does not continue until the prompting is performed by a user. See also Specifying Recipients for Network Messages in the section Network Maintenance.
Subnetworks and
recovery jobs defined for a network
require predefined symbols in order to pass information to the jobs of the
network. These predefined symbols have names that begin with P-C-.
For detailed information, see Predefined Symbols for Subnetworks
and Recovery Jobs.
You can use user exit routines that perform user-specific symbol maintenance tasks and symbol replace functions. For detailed information, refer to the following sections: