First install the module via
npm and do not forget to install the database driver as well:
Next you will need to enable support for decorators
as well as
MikroORM.init as part of bootstrapping your app:
Read more about all the possible configuration options in Advanced Configuration section.
You should provide list of directories, not paths to entities directly. If you want to do that
instead, you should use
entities array and use
You can pass additional options to the underlying driver (e.g.
driverOptions. The object will be deeply merged, overriding all internally used options.
Possible issues with circular dependencies
Your entities will most probably contain circular dependencies (e.g. if you use bi-directional
relationship). While this is fine, there might be issues caused by wrong order of entities
during discovery, especially when you are using the folder based way (via
The errors caused by circular dependencies are usually similar to this one:
If you encounter this, you have basically two options:
entitiesarray to have control over the order of discovery. You might need to play with the actual order you provide here, or possibly with the order of import statements.
- Use strings instead of references (e.g.
@OneToMany('Book', 'author)). The downside here is that you will loose the typechecking capabilities of the decorators.
Entity Discovery in TypeScript
ts-morph to perform analysis of source files
of entities to sniff types of all properties. This process can be slow if your project contains lots
of files. To speed up the discovery process a bit, you can provide more accurate paths where your
entity source files are:
You can also use different metadata provider or even write custom one:
Setting up the Commandline Tool
MikroORM ships with a number of command line tools that are very helpful during development,
like Schema Generator and Entity Generator. You can call this command from the NPM binary
directory or use
For CLI to be able to access your database, you will need to create
mikro-orm.config.js file that
exports your ORM configuration. TypeScript is also supported, just enable
useTsNode flag in your
package.json file. There you can also set up array of possible paths to
as well as use different file name:
Do not forget to install
Once you have the CLI config properly set up, you can omit the
parameter and the CLI config will be automatically used.
You can also use different names for this file, simply rename it in the
configPathsarray your in
package.json. You can also use
MIKRO_ORM_CLIenvironment variable with the path to override
Now you should be able to start using the CLI. All available commands are listed in the CLI help:
To verify your setup, you can use
mikro-orm debug command.
When you have CLI config properly set up, you can omit the
optionsparameter when calling
Then you will need to fork Entity Manager for each request so their identity maps will not
collide. To do so, use the
More info about
RequestContext is described here.
Now you can start defining your entities (in one of the