Crate sql_query_builder

Expand description

Write SQL queries in a simple and composable way.

The main goal is to find the best balance between write idiomatic SQL queries and manage scenarios of complex query composition mixed with conditional clauses.

§Quick Start

use sql_query_builder as sql;

let mut select = sql::Select::new()
  .select("id, login")
  .from("users")
  .where_clause("login = $1");

let is_admin = true;

if is_admin {
  select = select.where_clause("is_admin = true");
}

let query = select.as_string();

println!("{query}");

Output

SELECT id, login FROM users WHERE login = $1 AND is_admin = true

§Feature Flags

SQL Query Builder comes with the following optional features:

postgresql enable Postgres syntax
sqlite enable SQLite syntax

You can enable features like

# Cargo.toml

sql_query_builder = { version = "2.x.x", features = ["postgresql"] }

§How it’s works

In a simplified way, the lib has an API to allows you to write dynamic queries in a style similar to queries written in pure SQL and the result is a code idiomatic to both Rust and SQL. Additionally, the library will not try to understand what you write in the parameters and in some ways this is good as it removes a lot of verbosity to generate a SQL query, in contrast, debugging tends to be more difficult and silly errors can appear, the library has a debug() method which had a good output to minimize the effort of debugging complex queries.

More technically, consecutive calls to the same clause will accumulates values respecting the order of the calls, the two select produce the same SQL query.

use sql_query_builder as sql;

let select = sql::Select::new()
  .select("id, login");

let select = sql::Select::new()
  .select("id")
  .select("login");

Methods like limit and offset will override the previous value, the two select is equivalent

use sql_query_builder as sql;

let select = sql::Select::new()
  .limit("1000")
  .limit("123");

let select = sql::Select::new()
  .limit("123");

The library ignores the order between clauses so the two selects will produce the same query

use sql_query_builder as sql;

let select = sql::Select::new()
  .select("id, login")
  .from("users")
  .where_clause("login = $1");

let select = sql::Select::new()
  .from("users")
  .where_clause("login = $1")
  .select("id, login");

You can conditionally add a clause mutating the select

use sql_query_builder as sql;

let mut select = sql::Select::new()
  .select("id, login")
  .from("users")
  .where_clause("login = $1");

let should_includes_address = true;

if should_includes_address {
  select = select.inner_join("addresses on user.login = addresses.owner_login");
}

§Composition

Composition is very welcome to write complex queries, this feature makes the library shine

use sql_query_builder as sql;

fn project(select: sql::Select) -> sql::Select {
  select
    .select("u.id, u.name as user_name, u.login")
    .select("a.name as addresses_name")
    .select("o.name as product_name")
}

fn relations(select: sql::Select) -> sql::Select {
  select
    .from("users u")
    .inner_join("addresses a ON a.user_login = u.login")
    .inner_join("orders o ON o.user_login = u.login")
}

fn conditions(select: sql::Select) -> sql::Select {
  select
    .where_clause("u.login = $1")
    .where_clause("o.id = $2")
}

fn as_string(select: sql::Select) -> String {
  select.as_string()
}

let query = Some(sql::Select::new())
  .map(project)
  .map(relations)
  .map(conditions)
  .map(as_string)
  .unwrap();

println!("{query}");

Output (indented for readability)

SELECT u.id, u.name as user_name, u.login, a.name as addresses_name, o.name as product_name
FROM users u
INNER JOIN addresses a ON a.user_login = u.login
INNER JOIN orders o ON o.user_login = u.login
WHERE u.login = $1 AND o.id = $2

§Raw queries

You can use the raw method to reach some edge cases that are hard to rewrite into the Select syntax. The select.raw() method will put any SQL you define on top of the output

use sql_query_builder as sql;

let raw_query = "\
  select u.id as user_id, addr.* \
  from users u \
  inner join addresses addr on u.login = addr.owner_login\
";
let select = sql::Select::new()
  .raw(raw_query)
  .where_clause("login = $1");

To a more precisely use case your can use the select.raw_before() and select.raw_after()

use sql_query_builder as sql;

let raw_query = "\
  from users u \
  inner join addresses addr on u.login = addr.owner_login\
";
let select = sql::Select::new()
  .select("u.id as user_id, addr.*")
  .raw_before(sql::SelectClause::Where, raw_query)
  .where_clause("login = $1");

use sql_query_builder as sql;

let raw_query = "\
  from users u \
  inner join addresses addr on u.login = addr.owner_login\
";
let select = sql::Select::new()
  .select("u.id as user_id, addr.*")
  .raw_after(sql::SelectClause::Select, raw_query)
  .where_clause("login = $1");

§Debugging queries

Sometimes it’s more ease just print de current state of the query builder, to do so adds the .debug() method anywhere in the builder. In the example below, the where clause will not be printed because the debug was added before the clause

use sql_query_builder as sql;

let mut select = sql::Select::new()
  .select("id, login")
  .from("users")
  .debug()
  .where_clause("login = $1");

Prints to the standard output

-- ------------------------------------------------------------------------------
SELECT id, login
FROM users
-- ------------------------------------------------------------------------------

See the documentation for more builders like Insert, Update and Delete

Structs§

AlterTable: Builder to contruct a AlterTable command.
CreateIndex: Builder to contruct a CreateIndex command. Available only for the crate features postgresql and sqlite.
CreateTable: Builder to contruct a CreateTable command.
Delete: Builder to contruct a Delete command.
DropIndex: Builder to contruct a DropIndex command. Available only for the crate features postgresql and sqlite.
DropTable: Builder to contruct a DropTable command.
Insert: Builder to contruct a Insert command.
Select: Builder to contruct a Select command.
Transaction: Builder to contruct a Transaction block.
Update: Builder to contruct a Update command.
Values: Builder to contruct a Values command.

Enums§

AlterTableAction: All available params to be used in AlterTable::raw_before and AlterTable::raw_after methods on AlterTable builder
CreateIndexParams: All available params to be used in CreateIndex::raw_before and CreateIndex::raw_after methods on CreateIndex builder
CreateTableParams: All available params to be used in CreateTable::raw_before and CreateTable::raw_after methods on CreateTable builder
DeleteClause: All available clauses to be used in Delete::raw_before and Delete::raw_after methods on Delete builder
DropIndexParams: All available params to be used in DropIndex::raw_before and DropIndex::raw_after methods on DropIndex builder
DropTableParams: All available params to be used in DropTable::raw_before and DropTable::raw_after methods on DropTable builder
InsertClause: All available clauses to be used in Insert::raw_before and Insert::raw_after methods on Insert builder
SelectClause: All available clauses to be used in Select::raw_before and Select::raw_after methods on Select builder
UpdateClause: All available clauses to be used in Update::raw_before and Update::raw_after methods on Update builder
ValuesClause: All available clauses to be used in Values::raw_before and Values::raw_after methods on Values builder

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