docs/src/library_logical_plan.rs

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use datafusion::arrow::datatypes::{DataType, Field, Schema, SchemaRef};
use datafusion::error::Result;
use datafusion::logical_expr::builder::LogicalTableSource;
use datafusion::logical_expr::{Filter, LogicalPlan, LogicalPlanBuilder, TableScan};
use datafusion::prelude::*;
use std::sync::Arc;

#[test]
fn plan_1() -> Result<()> {
    // create a logical table source
    let schema = Schema::new(vec![
        Field::new("id", DataType::Int32, true),
        Field::new("name", DataType::Utf8, true),
    ]);
    let table_source = LogicalTableSource::new(SchemaRef::new(schema));

    // create a TableScan plan
    let projection = None; // optional projection
    let filters = vec![]; // optional filters to push down
    let fetch = None; // optional LIMIT
    let table_scan = LogicalPlan::TableScan(TableScan::try_new(
        "person",
        Arc::new(table_source),
        projection,
        filters,
        fetch,
    )?);

    // create a Filter plan that evaluates `id > 500` and wraps the TableScan
    let filter_expr = col("id").gt(lit(500));
    let plan = LogicalPlan::Filter(Filter::try_new(filter_expr, Arc::new(table_scan))?);

    // print the plan
    println!("{}", plan.display_indent_schema());

    Ok(())
}

#[test]
fn plan_builder_1() -> Result<()> {
    // create a logical table source
    let schema = Schema::new(vec![
        Field::new("id", DataType::Int32, true),
        Field::new("name", DataType::Utf8, true),
    ]);
    let table_source = LogicalTableSource::new(SchemaRef::new(schema));

    // optional projection
    let projection = None;

    // create a LogicalPlanBuilder for a table scan
    let builder = LogicalPlanBuilder::scan("person", Arc::new(table_source), projection)?;

    // perform a filter that evaluates `id > 500`, and build the plan
    let plan = builder.filter(col("id").gt(lit(500)))?.build()?;

    // print the plan
    println!("{}", plan.display_indent_schema());

    Ok(())
}