Struct perspective_client::View

pub struct View {
    pub name: String,
    /* private fields */
}

Fields

name: String

Implementations

impl View

pub fn new(name: String, client: Client) -> Self

pub async fn column_paths(&self) -> ClientResult<Vec<String>>

Returns an array of strings containing the column paths of the View without any of the source columns.

A column path shows the columns that a given cell belongs to after pivots are applied.

pub async fn dimensions(&self) -> ClientResult<ViewDimensionsResp>

Returns this View’s dimensions, row and column count, as well as those of the crate::Table from which it was derived.

• num_table_rows - The number of rows in the underlying crate::Table.
• num_table_columns - The number of columns in the underlying crate::Table (including the index column if this crate::Table was constructed with one).
• num_view_rows - The number of rows in this View. If this View has a group_by clause, num_view_rows will also include aggregated rows.
• num_view_columns - The number of columns in this View. If this View has a split_by clause, num_view_columns will include all column paths, e.g. the number of columns clause times the number of split_by groups.

pub async fn expression_schema( &self, ) -> ClientResult<HashMap<String, ColumnType>>

The expression schema of this View, which contains only the expressions created on this View. See View::schema for details.

pub async fn get_config(&self) -> ClientResult<ViewConfig>

A copy of the config object passed to the Table::view method which created this View.

pub async fn num_rows(&self) -> ClientResult<u32>

The number of aggregated rows in this View. This is affected by the “group_by” configuration parameter supplied to this view’s contructor.

Returns

The number of aggregated rows.

pub async fn schema(&self) -> ClientResult<HashMap<String, ColumnType>>

The schema of this View.

The View schema differs from the schema returned by Table::schema; it may have different column names due to expressions or columns configs, or it maye have different column types due to the application og group_by and aggregates config. You can think of Table::schema as the input schema and View::schema as the output schema of a Perspective pipeline.

JavaScript Examples

const [`View`] = await table.view({ columns: ["a", "b"] });
const schema = await view.schema(); // {a: "float", b: "string"}

pub async fn to_arrow(&self, window: ViewWindow) -> ClientResult<Bytes>

Serializes a View to the Apache Arrow data format.

pub async fn to_columns_string( &self, window: ViewWindow, ) -> ClientResult<String>

Serializes this View to a string of JSON data. Useful if you want to save additional round trip serialize/deserialize cycles.

pub async fn to_json_string(&self, window: ViewWindow) -> ClientResult<String>

Render this View as a JSON string.

pub async fn to_csv(&self, window: ViewWindow) -> ClientResult<String>

Serializes this View to CSV data in a standard format.

pub async fn delete(&self) -> ClientResult<()>

Delete this View and clean up all resources associated with it. View objects do not stop consuming resources or processing updates when they are garbage collected - you must call this method to reclaim these.

pub async fn get_min_max( &self, column_name: String, ) -> ClientResult<(String, String)>

Calculates the [min, max] of the leaf nodes of a column column_name.

Returns

A tuple of [min, max], whose types are column and aggregate dependent.

pub async fn on_update<T, U>( &self, on_update: T, options: OnUpdateOptions, ) -> ClientResult<u32>

where T: Fn(ViewOnUpdateResp) -> U + Send + Sync + 'static, U: Future<Output = ()> + Send + 'static,

This is used when constructing a super::table::Table from a View. The callback needs to be async to wire up the views on_update to the tables.

pub async fn remove_update(&self, update_id: u32) -> ClientResult<()>

Unregister a previously registered update callback with this View.

Arguments

• id - A callback id as returned by a recipricol call to View::on_update.

JavaScript Examples

const callback = () => console.log("Updated!");
const id = await view.on_update(callback);
await view.remove_update(id);

Python Examples

callback = lambda x: print(x)
cid = await view.on_update(callback)
await view.remove_update(cid)

Examples

let callback = |_| async { print!("Updated!") };
let cid = view.on_update(callback, OnUpdateOptions::default()).await?;
view.remove_update(cid).await?;

pub async fn on_delete( &self, on_delete: Box<dyn Fn() + Send + Sync + 'static>, ) -> ClientResult<u32>

Register a callback with this View. Whenever the View is deleted, this callback will be invoked.

Example

// attach an `on_delete` callback
view.on_delete(() => console.log("Deleted!"));

pub async fn remove_delete(&self, callback_id: u32) -> ClientResult<()>

Unregister a previously registered delete callback with this View.

Example

// remove an `on_delete` callback
const callback = () => console.log("Deleted!");
view.remove_delete(callback);

pub async fn collapse(&self, row_index: u32) -> ClientResult<u32>

Collapses the row at index.

This is used during a pivot.

pub async fn expand(&self, row_index: u32) -> ClientResult<u32>

Expands the row at index.

This is used during a pivot.

pub async fn set_depth(&self, depth: u32) -> ClientResult<()>

Set expansion depth of the pivot tree.

Trait Implementations

impl Clone for View

fn clone(&self) -> View

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for View

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.