Struct polars_sql::SQLContext

pub struct SQLContext { /* private fields */ }

The SQLContext is the main entry point for executing SQL queries.

Implementations

impl SQLContext

pub fn new() -> Self

Create a new SQLContext.

let ctx = SQLContext::new();

pub fn get_tables(&self) -> Vec<String>

Get the names of all registered tables, in sorted order.

pub fn register(&mut self, name: &str, lf: LazyFrame)

Register a LazyFrame as a table in the SQLContext.

let mut ctx = SQLContext::new();
let df = df! {
   "a" =>  [1, 2, 3],
}.unwrap().lazy();

ctx.register("df", df);

pub fn unregister(&mut self, name: &str)

Unregister a LazyFrame table from the SQLContext.

pub fn execute(&mut self, query: &str) -> PolarsResult<LazyFrame>

Execute a SQL query, returning a LazyFrame.

let mut ctx = SQLContext::new();
let df = df! {
   "a" =>  [1, 2, 3],
}
.unwrap();

ctx.register("df", df.clone().lazy());
let sql_df = ctx.execute("SELECT * FROM df").unwrap().collect().unwrap();
assert!(sql_df.equals(&df));

pub fn with_function_registry( self, function_registry: Arc<dyn FunctionRegistry> ) -> Self

add a function registry to the SQLContext the registry provides the ability to add custom functions to the SQLContext

pub fn registry(&self) -> &Arc<dyn FunctionRegistry>

Get the function registry of the SQLContext

pub fn registry_mut(&mut self) -> &mut dyn FunctionRegistry

Get a mutable reference to the function registry of the SQLContext

impl SQLContext

pub fn get_table_map(&self) -> PlHashMap<String, LazyFrame>

Get internal table map. For internal use only.

pub fn new_from_table_map(table_map: PlHashMap<String, LazyFrame>) -> Self

Create a new SQLContext from a table map. For internal use only

Trait Implementations

impl Clone for SQLContext

fn clone(&self) -> SQLContext

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Default for SQLContext

fn default() -> Self

Returns the “default value” for a type.