Function ensure_schema 

pub fn ensure_schema(
    tables: HashMap<String, HashMap<String, DataType>>,
    dialect: Dialect,
) -> MappingSchema

Build a MappingSchema from a nested map structure.

The input maps from table name → column name → data type, mirroring the common pattern of constructing schemas from DDL or metadata.

Example

use std::collections::HashMap;
use sqlglot_rust::schema::{ensure_schema, Schema};
use sqlglot_rust::ast::DataType;
use sqlglot_rust::Dialect;

let mut tables = HashMap::new();
let mut columns = HashMap::new();
columns.insert("id".to_string(), DataType::Int);
columns.insert("name".to_string(), DataType::Varchar(Some(255)));
tables.insert("users".to_string(), columns);

let schema = ensure_schema(tables, Dialect::Postgres);
assert!(schema.has_column(&["users"], "id"));