# mnesia_registry

### MODULE

mnesia_registry

### MODULE SUMMARY

Dump support for registries in erl_interface.

### DESCRIPTION

The module `mnesia_registry` is usually part of `erl_interface`, but for the time being, it is a part of the Mnesia application.

`mnesia_registry` is mainly an module intended for internal usage within OTP, but it has two functions that are exported for public use.

On C-nodes `erl_interface` has support for registry tables. These reside in RAM on the C-node but they may also be dumped into Mnesia tables. By default, the dumping of registry tables via `erl_interface` causes a corresponding Mnesia table to be created with `mnesia_registry:create_table/1` if necessary.

The tables that are created with these functions can be administered as all other Mnesia tables. They may be included in backups or replicas may be added etc. The tables are in fact normal Mnesia tables owned by the user of the corresponding `erl_interface` registries.

### EXPORTS

`create_table(Tab) -> ok | exit(Reason)`

This is a wrapper function for `mnesia:create_table/2` which creates a table (if there is no existing table) with an appropriate set of `attributes`. The table will only reside on the local node and its storage type will be the same as the `schema` table on the local node, ie. `{ram_copies,[node()]}` or `{disc_copies,[node()]}`.

It is this function that is used by `erl_interface` to create the Mnesia table if it did not already exist.

`create_table(Tab, TabDef) -> ok | exit(Reason)`

This is a wrapper function for `mnesia:create_table/2` which creates a table (if there is no existing table) with an appropriate set of `attributes`. The attributes and `TabDef` are forwarded to `mnesia:create_table/2`. For example, if the table should reside as `disc_only_copies` on all nodes a call would look like:

              TabDef = [{{disc_only_copies, node()|nodes()]}],
              mnesia_registry:create_table(my_reg, TabDef)

### See Also

mnesia(3), erl_interface(3)

### AUTHORS

Dan Gudmundsson - support@erlang.ericsson.se
Håkan Mattsson - support@erlang.ericsson.se

mnesia 4.3.2
Copyright © 1991-2006 Ericsson AB