Erlang document:

All Mnesia transactions, including all the schema update functions, either return value {atomic, Val} or the tuple {aborted, Reason}. Reason can be either of the atoms in the following list. The function error_description/1 returns a descriptive string that describes the error.

• nested_transaction. Nested transactions are not allowed in this context.
• badarg. Bad or invalid argument, possibly bad type.
• no_transaction. Operation not allowed outside transactions.
• combine_error. Table options illegally combined.
• bad_index. Index already exists, or was out of bounds.
• already_exists. Schema option to be activated is already on.
• index_exists. Some operations cannot be performed on tables with an index.
• no_exists. Tried to perform operation on non-existing (not-alive) item.
• system_limit. A system limit was exhausted.
• mnesia_down. A transaction involves records on a remote node, which became unavailable before the transaction was completed. Records are no longer available elsewhere in the network.
• not_a_db_node. A node was mentioned that does not exist in the schema.
• bad_type. Bad type specified in argument.
• node_not_running. Node is not running.
• truncated_binary_file. Truncated binary in file.
• active. Some delete operations require that all active records are removed.
• illegal. Operation not supported on this record.

Error can be Reason, {error, Reason}, or {aborted, Reason}. Reason can be an atom or a tuple with Reason as an atom in the first field.

The following examples illustrate a function that returns an error, and the method to retrieve more detailed error information:

• The function mnesia:create_table(bar, [{attributes, 3.14}]) returns the tuple {aborted,Reason}, where Reason is the tuple {bad_type,bar,3.14000}.

The function mnesia:error_description(Reason) returns the term {"Bad type on some provided arguments",bar,3.14000}, which is an error description suitable for display.

• error_description(Error :: term())

Example:

  MnesiaAssistant.Error.error_description(error)