sage.database.postgres_backends.postgres_mvcc package¶

Submodules¶

sage.database.postgres_backends.postgres_mvcc.connector module¶

sage.database.postgres_backends.postgres_mvcc.iterator module¶

sage.database.postgres_backends.postgres_mvcc.queries module¶

sage.database.postgres_backends.postgres_mvcc.queries.get_delete_query(table_name: str) → str¶

Build a SQL query to delete a RDF triple from a MVCC-PostgreSQL table.

Argument: Name of the SQL table from which the triple will be deleted.

Returns: A prepared SQL query that can be executed with a tuple (subject, predicate, object).

sage.database.postgres_backends.postgres_mvcc.queries.get_insert_many_query(table_name: str) → str¶

Build a SQL query to insert several RDF triples into a MVCC-PostgreSQL table.

Argument: Name of the SQL table in which the triples will be inserted.

Returns: A prepared SQL query that can be executed with a list of tuples (subject, predicate, object).

sage.database.postgres_backends.postgres_mvcc.queries.get_insert_query(table_name: str) → str¶

Build a SQL query to insert a RDF triple into a MVCC-PostgreSQL table.

Argument: Name of the SQL table in which the triple will be inserted.

Returns: A prepared SQL query that can be executed with a tuple (subject, predicate, object).

sage.database.postgres_backends.postgres_mvcc.queries.get_resume_query(subj: str, pred: str, obj: str, last_read: Tuple[str, str, str, datetime.datetime, datetime.datetime], table_name: str, symbol: str = '>=') → Tuple[str, str]¶

Get a prepared SQL query which resumes scanning for a triple pattern.

The SQL query rely on keyset pagination to resume query processing using an optimized Index Scan.

Args:

subj: Subject of the triple pattern.
pred: Predicate of the triple pattern.
obj: Object of the triple pattern.
last_read: The SQL row from which to resume scanning.
table_name: Name of the SQL table to scan for RDF triples.
symbol: Symbol used to perform the keyset pagination. Defaults to “>=”.

Returns:

A tuple with the prepared SQL query and its parameters.

sage.database.postgres_backends.postgres_mvcc.queries.get_start_query(subj: str, pred: str, obj: str, table_name: str) → Tuple[str, List[str]]¶

Get a prepared SQL query which starts scanning for a triple pattern.