UCAST SQL
This package is a part of ucast ecosystem. It provides an interpreter that can translates ucast conditions into SQL query.
Installation
npm i @ucast/sql
yarn add @ucast/sql
pnpm add @ucast/sql
Getting Started
Interpret conditions AST
In order to interpret something, we need 2 things: interpreter and AST. It's really easy to create interpreter just pick operators you want to use or pass all of them:
import {
createSqlInterpreter,
eq,
lt,
lte,
allInterpreters
} from '@ucast/sql';
const interpret = createSqlInterpreter({ eq, lt, lte });
const interpret = createSqlInterpreter(allInterpreters);
interpret
is a function that takes up to 3 parameters:
Condition
, condition to interpretoptions
, SQL dialect specific options that tells how to escape field, create placeholders and join related tables. @ucast/sql
provides options for the most popular SQL dialects.targetQuery
, optional, this is the parameter that @ucast/sql
passes as the 2nd one to joinRelation
function. This is useful when integrating with ORMs and their query builders.
For the sake of an example, we will create AST manually using Condition
from @ucast/core
:
import { CompoundCondition, FieldCondition } from '@ucast/core';
const condition = new CompoundCondition('and', [
new FieldCondition('gt', 'x', 5),
new FieldCondition('lt', 'y', 10),
]);
Now, we can combine these 2 together to get SQL condition:
import { CompoundCondition, FieldCondition } from '@ucast/core';
import { createSqlInterpreter, allInterpreters, pg } from '@ucast/sql';
const condition = new CompoundCondition('and', [
new FieldCondition('gt', 'x', 5),
new FieldCondition('lt', 'y', 10),
]);
const interpret = createSqlInterpreter(allInterpreters);
const [sql, replacements] = interpret(condition, {
...pg,
joinRelation: () => false
})
console.log(sql)
console.log(params)
Conditions on related table
Interpreter automatically detects fields with dot (.
) inside and interprets them as fields of a relation. It's possible to automatically inner join table using options.joinRelation
function. That function accepts 2 parameters: relation name and targetQuery (3rd argument of interpret
function). For example:
const condition = new FieldCondition('eq', 'address.street', 'some street');
const relations = { address: '"address"."id" = "address_id"' };
const [sql, params, joins] = interpret(condition, {
...pg,
joinRelation: relationName => relations.hasOwnProperty(relationName)
});
console.log(sql)
console.log(params)
console.log(joins)
Custom interpreter
Sometimes you may want to add custom operator or restrict supported operators. To do this, just pass desired operators manually:
import { createSqlInterpreter, eq, lt, gt, pg } from '@ucast/sql';
const interpret = createSqlInterpreter({ eq, lt, gt });
const condition = new FieldCondition('eq', 'x', true);
interpret(condition, pg);
To add a custom operator, all you need to do is to create a function that applies Condition
to instance of Query
object. Let's create an operator, that adds condition on publishedAt
field:
import { DocumentCondition } from '@ucast/core';
import {
SqlOperator,
createSqlInterpreter,
allInterpreters,
pg,
} from '@ucast/sql';
const isActive: SqlOperator<DocumentCondition<boolean>> = (node, query) => {
const operator = node.value ? '>=' : '<';
return query.where('publishedAt', operator, new Date());
};
const interpret = createSqlInterpreter({
...allInterpreters,
isActive,
});
const condition = new DocumentCondition('isActive', true);
const [sql, params] = interpret(condition, pg);
console.log(sql)
console.log(params)
Integrations
This library provides sub-modules that allows quickly integrate SQL interpreter with popular ORMs:
import { interpret } from '@ucast/sql/sequelize';
import { CompoundCondition, FieldCondition } from '@ucast/core';
import { Model, Sequelize, DataTypes } from 'sequelize';
const sequelize = new Sequelize('sqlite::memory:');
class User extends Model {}
User.init({
name: { type: DataTypes.STRING },
blocked: { type: DataTypes.BOOLEAN },
lastLoggedIn: { type: DataTypes.DATETIME },
});
const condition = new CompoundCondition('and', [
new FieldCondition('eq', 'blocked', false),
new FieldCondition('lt', 'lastLoggedIn', Date.now() - 24 * 3600 * 1000),
]);
const query = interpret(condition, User)
import { interpret } from '@ucast/sql/objection';
import { CompoundCondition, FieldCondition } from '@ucast/core';
import { Model } from 'objection';
import Knex from 'knex';
Model.knex(Knex({ client: 'pg' }));
class User extends Model {}
const condition = new CompoundCondition('and', [
new FieldCondition('eq', 'blocked', false),
new FieldCondition('lt', 'lastLoggedIn', Date.now() - 24 * 3600 * 1000),
]);
const query = interpret(condition, User.query())
import { interpret } from '@ucast/sql/mikro-orm';
import { CompoundCondition, FieldCondition } from '@ucast/core';
import { MikroORM, Entity, PrimaryKey, Property } from 'mikro-orm';
@Entity()
class User extends Model {
@PrimaryKey()
id!: number;
@Property()
blocked: boolean;
@Property()
name!: string;
@Property()
lastLoggedIn = new Date();
}
const condition = new CompoundCondition('and', [
new FieldCondition('eq', 'blocked', false),
new FieldCondition('lt', 'lastLoggedIn', Date.now() - 24 * 3600 * 1000),
]);
async function main() {
const orm = await MikroORM.init({
entities: [User],
dbName: ':memory:',
type: 'sqlite',
});
const qb = interpret(condition, orm.em.createQueryBuilder(User));
}
main().catch(console.error);
TypeScript Support
Written in TypeScript and supports type inference for supported ORMs.
Want to help?
Want to file a bug, contribute some code, or improve documentation? Excellent! Read up on guidelines for contributing
License
Apache License, Version 2.0