PortableTab.capnp_table module

class PortableTab.capnp_table.CapnpTable(tablename: str, db_dir=None)

Bases: CapnpManager

Class that represents a table containing Capnp records.

Parameters:

  • tablename (str) – Name of the table.

  • db_dir (Path-like, optional) – Base directory where the schema and tables are placed.

Notes

  • “db_dir” specifies the base directory where other tables will also be placed. Tables are placed in subdirectories with their tablename under the base directory.

append_records(records: Iterable[dict]) → None

Appends a set of record to the end of the table.

Paramaters

records: Iterable[dict]

Iterable that returns the records in order.

count_records() → int

Count the number of records in the table.

Returns:

The number of records.

Return type:

int

Notes

  • This method actually just reads the configuration file.

create(capnp_schema: str, record_type: str) → Path

Create table.

Parameters:

  • capnp_schema (str) – Record definition written in Capnp schema format.

  • record_type (str) – Type name of the record (struct) defined in the schema.

Returns:

Directory path where the created tables and schema will be stored.

Return type:

Path

Notes

  • Even if multiple structure types are defined in the schema, the type passed as record_type is used as the record type of this table.

create_trie_on(attr: str, func: Callable | None = None) → None

Create TRIE index on the specified attribute.

Paramters

attr: str

The name of target attribute.

func: Callable

Function to generate a set of strings to be indexed. If not specified, ‘str’ will be used.

Notes

  • The created index is saved in the same directory as the page files with the file name “<attr>.trie”.

delete() → None

Delete the table.

Notes

  • This method actually deletes the subtree containing the table.

delete_trie_on(attr: str)

Delete TRIE index on the specified attribute.

Paramters

attr: str

The name of target attribute.

Notes

  • Delete any file named “<attr>.trie” in the same directory as the page files.

  • If the index is already loaded, unload it.

get_config() → Path

Get the contents of the config file of the table.

get_dir() → Path

Get the directory where the table are placed.

get_list_type() → Any

Get the list type.

Returns:

Capnp type name corresponding to a list of records.

Return type:

Any

Notes

  • The type is defined by the schema file name.

get_record(pos: int, as_dict: bool = False) → Any

Get a record from the table at pos.

Parameters:

  • pos (int) – Position of the target record.

  • as_dict (bool [False]) – Specifies whether records are returned in dict format.

Returns:

When “as_dict” is set to True, it returns a dict object. Otherwise, it returns a record_type object.

Return type:

Any

get_record_type() → Any

Get the record type.

Returns:

Capnp type name corresponding to a record.

Return type:

Any

Notes

  • The type is defined by the schema file name.

open_trie_on(attr: str) → RecordTrie

Open TRIE index on the specified attribute.

Paramters

attr: str

The name of target attribute.

returns:

The TRIE index.

rtype:

RecordTrie

Notes

  • The index is mmapped from the file name “<attr>.trie”, in the same directory as the page files.

retrieve_records(limit: int | None = None, offset: int | None = None, as_dict: bool = False) → Iterator[Any]

Get a iterator that retrieves records from the table.

Paramaters

limit: int, optional

Max number of records to be retrieved. If omitted, all records are retrieved.

offset: int, optional

Specifies the number of records to be retrieved from. If omitted, the retrieval is performed from the beginning.

as_dict: bool [False]

Specifies whether records are returned in dict format.

returns:

When “as_dict” is set to True, it returns a iterator of dict. Otherwise, it returns a iterator of record_type object.

rtype:

Iterator[Any]

search_records_on(attr: str, value: str, funcname: str = 'get') → list

Search value from the table on the specified attribute.

Paramters

attr: str

The name of target attribute.

value: str

The target value.

funcname: str

The name of search method. - “get” searches for records that exactly match the value. - “prefixes” searches for records that contained in the value. - “keys” searches for records that containing the value.

returns:

List of records.

rtype:

List[Record]

Notes

  • TRIE index must be created on the column before searching.

  • The TRIE index file will be automatically opened if it exists.

set_config(config: dict) → None

Set the contents of the config file of the table.

Notes

  • This method overwrite the config file completery.

unload() → None

Release loaded resources manually, including the capnp module corresponding to this table.

update_records(updates: dict) → bool

Updates records in the table that has already been output to a file.

Paramaters

updates: dict

A dict whose keys are the positions of records to be updated and whose values are the contents to be updated.

The format of the values are a dict of field name/value pairs to be updated.

Examples

>>> table.update_records({
    15: {
            "name": "Bernardo de la Paz",
            "job": "Professor",
    },
})

Notes

  • This process is very slow and should not be called if possible.