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.TH snmpa_local_db 3 "snmp 4.11" "Ericsson AB" "ERLANG MODULE DEFINITION"
.SH MODULE
snmpa_local_db \- The SNMP built-in database
.SH DESCRIPTION
.LP
The module \fIsnmpa_local_db\fR 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\&.
.LP
There is a scaling problem with this database\&.
.RS 2
.TP 2
*
Insertions and deletions are inefficient for large tables\&.
.RE
.LP
This problem is best solved by using Mnesia instead\&.
.LP
The following functions describe the interface to \fIsnmpa_local_db\fR\&. Each function has a Mnesia equivalent\&. The argument \fINameDb\fR is a tuple \fI{Name, Db}\fR where \fIName\fR is the symbolic name of the managed object (as defined in the MIB), and \fIDb\fR is either \fIvolatile\fR or \fIpersistent\fR\&. \fImnesia\fR is not possible since all these functions are \fIsnmpa_local_db\fR specific\&.
.SH COMMON DATA TYPES
.LP
In the functions defined below, the following types are used:
.RS 2
.TP 2
*
\fINameDb = {Name, Db}\fR
.TP 2
*
\fIName = atom(), Db = volatile | persistent\fR
.TP 2
*
\fIRowIndex = [int()]\fR
.TP 2
*
\fICols = [Col] | [{Col, Value}], Col = int(), Value = term()\fR
.RE
.LP
where \fIRowIndex\fR denotes the last part of the OID, that specifies the index of the row in the table\&. \fICols\fR 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\&.
.SH EXPORTS
.LP
.B
dump() -> ok | {error, Reason}
.br
.RS
.TP
Types
Reason = term()
.br
.RE
.RS
.LP
This function can be used to manually dump the database to file\&.
.RE
.LP
.B
match(NameDb, Pattern)
.br
.RS
.LP
Performs an ets/dets matching on the table\&. See Stdlib documentation, module ets, for a description of \fIPattern\fR and the return values\&.
.RE
.LP
.B
print()
.br
.B
print(TableName)
.br
.B
print(TableName, Db)
.br
.RS
.TP
Types
TableName = atom()
.br
.RE
.RS
.LP
Prints the contents of the database on screen\&. This is useful for debugging since the \fISTANDARD-MIB\fR and \fIOTP-SNMPEA-MIB\fR (and maybe your own MIBs) are stored in \fIsnmpa_local_db\fR\&.
.LP
\fITableName\fR is an atom for a table in the database\&. When no name is supplied, the whole database is shown\&.
.RE
.LP
.B
table_create(NameDb) -> bool()
.br
.RS
.LP
Creates a table\&. If the table already exist, the old copy is destroyed\&.
.LP
Returns \fIfalse\fR if the \fINameDb\fR argument is incorrectly specified, \fItrue\fR otherwise\&.
.RE
.LP
.B
table_create_row(NameDb, RowIndex, Row) -> bool()
.br
.RS
.TP
Types
Row = {Val1, Val2, \&.\&.\&., ValN}
.br
Val1 = Val2 = \&.\&.\&. = ValN = term()
.br
.RE
.RS
.LP
Creates a row in a table\&. \fIRow\fR is a tuple with values for all columns, including the index columns\&.
.RE
.LP
.B
table_delete(NameDb) -> void()
.br
.RS
.LP
Deletes a table\&.
.RE
.LP
.B
table_delete_row(NameDb, RowIndex) -> bool()
.br
.RS
.LP
Deletes the row in the table\&.
.RE
.LP
.B
table_exists(NameDb) -> bool()
.br
.RS
.LP
Checks if a table exists\&.
.RE
.LP
.B
table_get_row(NameDb, RowIndex) -> Row | undefined
.br
.RS
.TP
Types
Row = {Val1, Val2, \&.\&.\&., ValN}
.br
Val1 = Val2 = \&.\&.\&. = ValN = term()
.br
.RE
.RS
.LP
\fIRow\fR is a tuple with values for all columns, including the index columns\&.
.RE
.SH SEE ALSO
.LP
ets(3), dets(3), snmp_generic(3)
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