Schema Builder

A fluent API for conveniently constructing Apache Arrow schemas.

Overview

SchemaBuilder lets you define schemas intuitively through method chaining, eliminating the need to manually create Arrow Field objects and combine them into a Schema.

Basic Usage

use dbx_core::SchemaBuilder;
use arrow::datatypes::DataType;

let schema = SchemaBuilder::new()
    .column("id", DataType::Int64, false)
    .column("name", DataType::Utf8, true)
    .build();

Database Integration (Table Creation)

Use the create_table_with_builder method on Database for convenient table creation.

use dbx_core::Database;

let db = Database::open_in_memory()?;

// Create table with schema builder
db.create_table_with_builder("users", |builder| {
    builder
        .id("id")
        .text("name").not_null()
        .text("email").not_null()
        .int32("age")
})?;

Convenience Methods

Shorthand methods are provided for common data types:

id(name): Int64, NOT NULL
text(name): Utf8, nullable by default
int32(name): Int32, nullable by default
int64(name): Int64, nullable by default
float64(name): Float64, nullable by default
boolean(name): Boolean, nullable by default
timestamp(name): Timestamp(Millisecond), nullable by default

let schema = SchemaBuilder::new()
    .id("user_id")
    .text("username")
    .int32("age")
    .boolean("is_active")
    .timestamp("created_at")
    .build();

Nullability Control

Columns created with convenience methods are nullable by default (except id). Use not_null() or nullable() to change this.

let schema = SchemaBuilder::new()
    .text("email").not_null()     // required field
    .text("nickname").nullable()  // optional field
    .build();

Next Steps

Query Builder — Fluent API for querying data
SQL Reference — Standard SQL usage in DBX