---
lang: en
title: 'Discovering models from relational databases'
keywords: LoopBack 4.0, LoopBack-Next
sidebar: lb4_sidebar
permalink: /doc/en/lb4/Discovering-models.html
---

## Synopsis

LoopBack makes it simple to create models from an existing relational database.
This process is called _discovery_ and is supported by the following connectors:

- Cassandra
- MySQL
- Oracle
- PostgreSQL
- SQL Server
- IBM DB2
- IBM DashDB
- IBM DB2 for z/OS
- [SAP HANA](https://www.npmjs.org/package/loopback-connector-saphana) - Not
  officially supported;

## Overview

Models can be discovered from a supported datasource by running the
`lb4 discover` command.

**The LoopBack project must be built and contain the built datasource files in
`PROJECT_DIR/dist/datasources/*.js`**

### Options

`--dataSource`: Put a valid datasource name here to skip the datasource prompt

`--views`: Choose whether to discover views. Default is true

`--all`: Skips the model prompt and discovers all of them

`--outDir`: Specify the directory into which the `model.model.ts` files will be
placed. Default is `src/models`

`--schema`: Specify the schema which the datasource will find the models to
discover