docstore.pl -- Document-oriented database

Generic thread-safe in-memory transactional store for dict terms.

ds_open(+File) is det
Opens the database file. Throws error(docstore_is_open) when the database is already open.
ds_close is det
Closes the database. Removes in-memory data. Runs close hooks. Hooks are ran before the file is closed and data is purged from memory. Throws error(database_is_not_open) when the database file is not open.
ds_snapshot(+File) is det
Writes the current database snapshot into the file.
ds_snapshot is det
Writes the snapshot of current database contents into its file. Implemented by running ds_snapshot/1 into a file (with a random name) and renaming the file using rename_file/2.
ds_hook(+Col, +Action, :Goal) is det
Adds new save/remove hook. Action is one of: before_save, before_remove. before_save hooks are executed before insert and update. before_remove hooks are executed before the document removal. During update only the updated fields are passed to the before_save hooks. Hooks are run in the current transaction. Hooks that fail or throw exception will end the transaction and discard changes.
ds_insert(Doc) is det
Same as ds_insert/2 but the generated ID is ignored.
ds_insert(+Doc, -Id) is det
Same as ds_insert/3 but collection name is taken from dict tag.
ds_insert(+Col, +Doc, -Id) is det
Inserts new document into the given collection. Gives back the generated ID. Document must be a dict. All values in the dict must be ground. Throws error(doc_has_id) when the document has the $id key. Runs before_save hooks.
ds_update(+Doc) is det
Updates the given document. Only changed properties are updated. Throws error if Doc contains no $id. Ignores updates to $id. Runs before_save hooks. Throws error(no_such_doc(Id)) when no document with the given Id exists.
ds_update(+Id, +Doc) is det
Updates the given document. The document id inside the document is ignored.
ds_upsert(+Doc) is det
Same as ds_upsert/2 but ignores the generated id.
ds_upsert(+Doc, -Id) is det
Same as ds_upsert/3 but uses dict tag as collection name when inserting.
ds_upsert(+Col, +Doc, -Id) is det
Inserts or updates the given document.
ds_move(+Col, +Id, +NewCol) is det
Moves the given document into the new collection. Throws error when the document does not exist.
ds_col_get(+Col, +Id, -Doc) is semidet
Retrieves entry with the given id. Fails when the document with the given id does not exist or is not in the given collection.
ds_col_get(+Col, +Id, +Keys, -Doc) is semidet
Retrieves entry with the given id. Retrieves subset of properties. Fails when the document with the given id does not exist or is not in the given collection.
ds_all(+Col, -List) is det
Finds list of all documents in the given collection.
ds_all(+Col, +Keys, -List) is det
Finds list of all documents in the given collection. Retrieves subset of keys. Subset will always contain '$id'.
ds_all_ids(+Col, -List) is det
Retrieves the list of all document IDs in the collection.
ds_find(+Col, +Cond, -List) is semidet
Finds collection entries that satisfy condition(s). Cond is one of: Key = Value, Key \= Value, Key > Value, Key < Value, Key >= Value, Key =< Value, member(Value, Key), (Cond1, Cond2), (Cond1 ; Cond2).
ds_find(+Col, +Cond, +Keys, -List) is semidet
Same as ds_find/3 but retrieves subset of keys.
ds_collection(?Id, ?Col) is semidet
Finds which collection the document belongs to.
ds_col_remove(+Col, +Id) is det
Removes the given document. Does nothing when the document does not exist. Runs before_remove hooks.
ds_col_remove_cond(+Col, +Cond) is det
Removes all documents from the collection that match the condition. Runs before_remove hooks. Cond expressions are same as in ds_find/3.
ds_remove_col(Col) is det
Removes all documents from the given collection. Is equivalent of running ds_remove/1 for each document in the collection. Runs before_remove hooks.
ds_tuples(+Col, +Keys, -Values) is nondet
Provides backtrackable predicate-like view of documents. It does not support built-in indexing and therefore can be slow for purposes where some values are restricted.
ds_remove_key(+Id, +Key) is det
Removes key from the given document. Does nothing when the document or entry does not exist.
ds_col_add_key(+Col, +Key, +Default) is det
Adds each document new key with the default value. Runs before_save hooks.
ds_col_remove_key(+Col, +Key) is det
Removes given key from the document collection. Throws error(cannot_remove_id) when key is $id. save_before hooks are not executed.
ds_col_rename(+Col, +ColNew) is det
Rename collection. Relatively expensive operation in terms of journal space. Needs entry per document in the collection.
ds_col_rename_key(+Col, +Key, +KeyNew) is det
Renames a key in collection. Relatively expensive operation in terms of journal space. Needs 2 entries per document in the collection. Does not run hooks.
ds_transactional(:Goal) is det
Runs given goal that modifies the database contents in a transactional mode. When the goal throws exception or fails, no changes by it are persisted.
ds_id(+Doc, -Id) is det
Extracts document id from the given document. Equivalent to Doc.'$id'.
ds_set_id(+In, +Id, -Out) is det
Sets the document id. Throws error when the document is not a dict or id is not an atom.
ds_uuid(-Id) is det
Generates UUID version 4 identifier. More info: http://en.wikipedia.org/wiki/Universally_unique_identifier