VOXI core

WIP warning

The API design can suffers break changes.** **This project isn't finished and shouldn't be used in production yet.

Objective

A type-safe, serializable SQL query builder with rich value types, designed for database-agnostic applications with client-server communication. An Abstract Syntax Tree (AST) for building dynamic SQL queries.

Sintaxes available:

• Group by
• Sub-queries
• Joins
• Combinations
• Aggregated functions
• String functions
• Arithmetic expressions

Allowed types:

• i32 and i64
• boolean
• naive date
• naive datetime
• string
• uuid
• decimal

Why can I need this?

You can serialize and deserialize the condition (or any other structure).

Arithmetic operators are defined for convenient operations with fields and literal values.

Example

let id = TableField::new("PRODUCT.id");
let name = TableField::new("PRODUCT.name");
let price = TableField::new("PRODUCT.price");
let discount = TableField::new("PRODUCT.discount");

let log_expr = id
	.equal(1)
	.or(name.include(vec!["PS5", "XBOX"]))
	.exp()
	.and(price.less(1000 - discount));

let sql = args_to_str(log_expr).unwrap();
assert_eq!(
	sql,
	r#"("PRODUCT"."id" = 1 OR "PRODUCT"."name" IN ('PS5','XBOX')) AND "PRODUCT"."price" < 1000 - "PRODUCT"."discount""#
);

SQLx

Can be paired with SQLx, when for all literal values will be defined arguments (binds), protecting against SQL injection. (It will be released in a separated project voxi-dataset)

SQLx is useful for constants queries, but sometimes you can need dynamic constructions of sources, fields or conditions.

Example

// Generate query `SELECT "symbol" FROM "symbol" WHERE "symbol" = $1`
let query = QueryBuilder::new()
	.field("symbol")
	.from("symbol")
	.where_c(FieldName::new("symbol").equal("AAPL"))
	.build()
	.unwrap();

let executor = ExecutorSQLxPostgres::new(query);
let query_sqlx = executor.query().fetch_all(&pool);

let result = executor::block_on(query_sqlx)?;
for row in result.iter() {
	let id = row.try_get::<String, _>("symbol").unwrap();
	println!("{}", id);
}

Current state and future changes

Some comments and unit test may be missing.

For now it provides support only syntax for Postgres.

Because it has many goals, probably this project needs to be divided in more projects.

• voxi-sql. AST for dynamic SQL.
• voxi-dataset. Types to manipulate relational database tables.

Many dependencies should be activated by features, like use of uuid, rust_decimal, chrono and sqlx.