Crate ursa_sql 

Ursa SQL: DataFusion’s dialect plus Ursa’s own statements.

parse_sql splits a string into UrsaStatements. execute runs one on an engine session (see ursa_engine::new_session). Statements DataFusion knows are planned and run by DataFusion, except that one may not drop a table a graph uses, or replace it by one the graph no longer fits (ursa_engine::graph::check_ddl). CREATE PROPERTY GRAPH and DROP PROPERTY GRAPH define graphs (see property_graph for the subset of SQL/PGQ supported); SHOW GRAPHS and DESCRIBE GRAPH describe them. SHOW ursa.<setting> shows one of Ursa’s settings, and SHOW ALL lists them with DataFusion’s (see settings). SHOW TABLES lists the tables and views, without information_schema’s own views. read_parquet(...), read_csv(...) and read_json(...) open their files before a statement is planned (see ursa_engine::read_functions).

A session may have a .ursa database (database): open_session opens one, and ATTACH 'club.ursa' opens one in an in-memory session that has defined nothing yet. In such a session, statements that define or drop views, external tables and graphs are kept in the database’s catalog file. Relative file paths resolve against the current directory when a statement runs, as in DuckDB; a stored definition’s paths are rewritten relative to the directory holding the file (see database).

Re-exports

pub use database::open_session;

Modules

database

Statements in a session with a .ursa database.

graph_table

SQL/PGQ’s GRAPH_TABLE ( … ), rewritten before sqlparser sees it (#296).

property_graph

The table clauses of CREATE PROPERTY GRAPH: SQL/PGQ’s element tables (#295).

Structs

Attach

CreatePropertyGraph

CREATE PROPERTY GRAPH: Ursa’s subset of SQL/PGQ (see crate::property_graph).

DescribeGraph

DropPropertyGraph

OpenOptions

How to open a database.

UrsaParser

Ursa’s parser: DataFusion’s, with Ursa’s statements recognised first.

Enums

UrsaStatement

One statement of Ursa SQL.

Constants

DEFAULT_RECURSION_LIMIT

Same as sqlparser’s and DataFusion’s default.

Functions

execute

Run one statement on ctx. The returned frame is lazy for a query, and already applied for DDL (as with SessionContext::sql).

execute_with_text

execute, with the statement’s text as written (from parse_sql_with_text_for), which a database stores when the statement’s Display does not round-trip.

parse_sql

Parse sql (one or more statements separated by ;) with the generic dialect.

parse_sql_for

Parse sql with the session’s configured dialect and recursion limit.

parse_sql_with_text_for

parse_sql_for, with each statement’s text as written (see execute_with_text).