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 values.

       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)