snmpa_local_db(3erl) Erlang Module Definition snmpa_local_db(3erl)
NAME
snmpa_local_db - The SNMP built-in database
DESCRIPTION
The module snmpa_local_db contains functions for implementing tables (and variables) using the SNMP built-in database. The database exists
in two instances, one volatile and one persistent. The volatile database is implemented with ets. The persistent database is implemented
with dets.
There is a scaling problem with this database.
* Insertions and deletions are inefficient for large tables.
This problem is best solved by using Mnesia instead.
The following functions describe the interface to snmpa_local_db . Each function has a Mnesia equivalent. The argument NameDb is a tuple
{Name, Db} where Name is the symbolic name of the managed object (as defined in the MIB), and Db is either volatile or persistent . mnesia
is not possible since all these functions are snmpa_local_db specific.
COMMON DATA TYPES
In the functions defined below, the following types are used:
* NameDb = {Name, Db}
* Name = atom(), Db = volatile | persistent
* RowIndex = [int()]
* Cols = [Col] | [{Col, Value}], Col = int(), Value = term()
where RowIndex denotes the last part of the OID, that specifies the index of the row in the table. Cols is a list of column numbers in case
of a get operation, and a list of column numbers and values in case of a set operation.
EXPORTS
dump() -> ok | {error, Reason}
Types Reason = term()
This function can be used to manually dump the database to file.
match(NameDb, Pattern)
Performs an ets/dets matching on the table. See Stdlib documentation, module ets, for a description of Pattern and the return val-
ues.
print()
print(TableName)
print(TableName, Db)
Types TableName = atom()
Prints the contents of the database on screen. This is useful for debugging since the STANDARD-MIB and OTP-SNMPEA-MIB (and maybe
your own MIBs) are stored in snmpa_local_db .
TableName is an atom for a table in the database. When no name is supplied, the whole database is shown.
table_create(NameDb) -> bool()
Creates a table. If the table already exist, the old copy is destroyed.
Returns false if the NameDb argument is incorrectly specified, true otherwise.
table_create_row(NameDb, RowIndex, Row) -> bool()
Types Row = {Val1, Val2, ..., ValN}
Val1 = Val2 = ... = ValN = term()
Creates a row in a table. Row is a tuple with values for all columns, including the index columns.
table_delete(NameDb) -> void()
Deletes a table.
table_delete_row(NameDb, RowIndex) -> bool()
Deletes the row in the table.
table_exists(NameDb) -> bool()
Checks if a table exists.
table_get_row(NameDb, RowIndex) -> Row | undefined
Types Row = {Val1, Val2, ..., ValN}
Val1 = Val2 = ... = ValN = term()
Row is a tuple with values for all columns, including the index columns.
SEE ALSO
ets(3erl), dets(3erl), snmp_generic(3erl)
Ericsson AB snmp 4.19 snmpa_local_db(3erl)