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Version: 4.5

Naming Strategy

When mapping your entities to database tables and columns, their names will be defined by naming strategy. There are 3 basic naming strategies you can choose from:

  • UnderscoreNamingStrategy - default of all SQL drivers
  • MongoNamingStrategy - default of MongoDriver
  • EntityCaseNamingStrategy - uses unchanged entity and property names

You can override this when initializing ORM. You can also provide your own naming strategy, just implement NamingStrategy interface and provide your implementation when bootstrapping ORM:

class YourCustomNamingStrategy implements NamingStrategy {

const orm = await MikroORM.init({
namingStrategy: YourCustomNamingStrategy,

You can also extend AbstractNamingStrategy which implements one method for you - getClassName() that is used to map entity file name to class name.

Naming Strategy in mongo driver

MongoNamingStrategy will simply use all field names as they are defined. Collection names will be translated into lower-cased dashed form:

MyCoolEntity will be translated into my-cool-entity collection name.

Naming Strategy in SQL drivers

MySqlDriver defaults to UnderscoreNamingStrategy, which means your all your database tables and columns will be lower-cased and words divided by underscored:

CREATE TABLE `author` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`created_at` datetime(3) DEFAULT NULL,
`updated_at` datetime(3) DEFAULT NULL,
`terms_accepted` tinyint(1) DEFAULT NULL,
`name` varchar(255) DEFAULT NULL,
`email` varchar(255) DEFAULT NULL,
`born` datetime DEFAULT NULL,
`favourite_book_id` int(11) DEFAULT NULL,

NamingStrategy API

NamingStrategy.getClassName(file: string, separator?: string): string

Return a name of the class based on its file name.

NamingStrategy.classToTableName(entityName: string): string

Return a table name for an entity class.

NamingStrategy.propertyToColumnName(propertyName: string): string

Return a column name for a property.

NamingStrategy.referenceColumnName(): string

Return the default reference column name.

NamingStrategy.joinColumnName(propertyName: string): string

Return a join column name for a property.

NamingStrategy.joinTableName(sourceEntity: string, targetEntity: string, propertyName: string): string

Return a join table name. This is used as default value for pivotTable.

NamingStrategy.joinKeyColumnName(entityName: string, referencedColumnName?: string): string

Return the foreign key column name for the given parameters.