1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69
// Licensed to the Apache Software Foundation (ASF) under one // or more contributor license agreements. See the NOTICE file // distributed with this work for additional information // regarding copyright ownership. The ASF licenses this file // to you under the Apache License, Version 2.0 (the // "License"); you may not use this file except in compliance // with the License. You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, // software distributed under the License is distributed on an // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY // KIND, either express or implied. See the License for the // specific language governing permissions and limitations // under the License. //! Table API for building a logical query plan. This is similar to the Table API in Ibis //! and the DataFrame API in Apache Spark use crate::error::Result; use crate::logicalplan::{Expr, LogicalPlan}; use std::sync::Arc; /// Table is an abstraction of a logical query plan pub trait Table { /// Select columns by name fn select_columns(&self, columns: Vec<&str>) -> Result<Arc<dyn Table>>; /// Create a projection based on arbitrary expressions fn select(&self, expr: Vec<Expr>) -> Result<Arc<dyn Table>>; /// Create a selection based on a filter expression fn filter(&self, expr: Expr) -> Result<Arc<dyn Table>>; /// Perform an aggregate query fn aggregate( &self, group_expr: Vec<Expr>, aggr_expr: Vec<Expr>, ) -> Result<Arc<dyn Table>>; /// limit the number of rows fn limit(&self, n: usize) -> Result<Arc<dyn Table>>; /// Return the logical plan fn to_logical_plan(&self) -> Arc<LogicalPlan>; /// Return an expression representing a column within this table fn col(&self, name: &str) -> Result<Expr>; /// Create an expression to represent the min() aggregate function fn min(&self, expr: &Expr) -> Result<Expr>; /// Create an expression to represent the max() aggregate function fn max(&self, expr: &Expr) -> Result<Expr>; /// Create an expression to represent the sum() aggregate function fn sum(&self, expr: &Expr) -> Result<Expr>; /// Create an expression to represent the avg() aggregate function fn avg(&self, expr: &Expr) -> Result<Expr>; /// Create an expression to represent the count() aggregate function fn count(&self, expr: &Expr) -> Result<Expr>; /// Return the index of a column within this table's schema fn column_index(&self, name: &str) -> Result<usize>; }