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Introduction to @platformatic/sql-mapper

@platformatic/sql-mapper is the underlining utility that Platformatic DB uses to create useful utilities to manipulate your SQL database using JavaScript.

This module is bundled with Platformatic DB via a fastify plugin The rest of this guide shows how to use this module directly.

Install​

npm i @platformatic/sql-mapper

API​

connect(opts) : Promise​

It will inspect a database schema and return an object containing:

  • db — A database abstraction layer from @databases.
  • sql — The SQL builder from @databases.
  • entities — An object containing a key for each table found in the schema, with basic CRUD operations. See Entity Reference for details.

The valid options are:

  • connectionString — The Database connection string.
  • poolSize - Maximum number of connections in the connection pool. The default poolSize is 10.
  • log — A logger object (like Pino).
  • onDatabaseLoad — An async function that is called after the connection is established. It will receive db and sql as parameters.
  • ignore — An object used to ignore specified tables from building entities (i.e. { 'versions': true } will ignore the versions table).
  • include — An object used to explicitly identify tables for which you would like entities built (i.e. { 'versions': true } will build a versions entity from the versions table and ignore all other tables).
  • autoTimestamp — Flag to enable automatic generation of a timestamp when inserting or updating records.
  • hooks — An object to customize entity API functions for each entity. Your custom function will receive the original function as the first parameter and all other parameters passed to it.
  • cache — Flag to enable cache and dedupe features (default is false, i.e. disabled). This is currently only supported during schema enumeration.

createConnectionPool(opts) : Promise​

It will inspect a database schema and return an object containing:

The valid options are:

  • connectionString — The Database connection string
  • poolSize - Maximum number of connections in the connection pool (default poolSize is 10)
  • log — A logger object (like Pino)

This utility is useful if you just need to connect to the db without generating any entity.

Code samples​

const { connect } = require('@platformatic/sql-mapper')
const { pino } = require('pino')

const logger = pino()

async function onDatabaseLoad (db, sql) {
  await db.query(sql`CREATE TABLE pages (
    id SERIAL PRIMARY KEY,
    title VARCHAR(255) NOT NULL
  );`)
}
const connectionString =
  'postgres://postgres:postgres@localhost:5432/postgres'
const mapper = await connect({
  connectionString,
  log: logger,
  onDatabaseLoad,
  ignore: {},
  hooks: {
    Page: {
      find: async function(_find, opts) {
        console.log('hook called');
        return await _find(opts)
      }
    }
  },
  cache: true
})
const pageEntity = mapper.entities.page

await mapper.db.query(mapper.sql`SELECT * FROM pages`)
await mapper.db.find('option1', 'option2')